Interlinked Sustainability Aspects of Low-Rise Residential Family House Development in Slovakia

Abstract

This paper compares the sustainability aspects of three family houses according to the Slovak building environmental assessment system (BEAS). Various categories of family houses were evaluated, including site selection, project planning, building construction, indoor environment, energy performance, and water and waste management. Based on the results, Family Houses 3 and 2 are certified as BEAS SILVER, with scores of 2.46 and 2.01, respectively. Family House 1 is certified as BEAS BRONZE, with an overall score of 1.44. The results show, not only the importance of the site in terms of availability, connectivity to the network and the potential to use renewable energy sources, but also the importance of the design and construction of the building, including the application of environmentally friendly building materials, ensuring the quality of the indoor environment and the energy efficiency of the building. The aims of this study were to highlight the current trend in the design and construction of low-rise residential family houses in Slovakia and to identify gaps in the design and construction of key sustainability aspects through the existing building environmental assessment system. In the future, many low-rise residential family houses will be assessed to modify and validate BEAS.

1. Introduction

Reducing the impact of buildings on the natural environment and people is a key factor when planning the sustainable zones and towns in the world. For this reason, it is very important to design high performance, energy efficient and resource-efficient buildings, tailored to the needs of the occupant’s objectives and well-being. Sustainable buildings are defined by assessment systems, which rate and certify them and indicate the extent to which the building is sustainable [1]. The different ways of assessing buildings are the certification schemes used around the world. Many researchers and practitioners use, compare, verify and annotate them, and the development of green rating systems has been systematically reviewed previously [2], including LEED, BREEAM, CASBEE and Green Star NZ. The similarities, differences, strengths, and weaknesses of the green rating systems are identified based on the research manuals. The total categories, sub-categories, points, and mandatory credits must be increased to more comprehensively assess the sustainability of a project. For example, in the LEED scheme, the total points and mandatory credits were doubled, from version 2 to version 4, along with the addition of two more categories. BREEAM is considered the strongest rating system, in which the environment and society are carefully assessed, along with the consideration of the economy and institutions. The weakest system could be Green Star NZ, as it only focuses on one pillar of sustainability, i.e., the environment. Society is critically evaluated by LEED. CASBEE is a well-balanced tool in relation to the environment, society, and economy assessments. However, no rating scheme could assess a project in relation to all aspects of sustainability. Since there is no single assessment scheme for building refurbishment in Malaysia, Kamaruzzaman et al. [3] aims to develop a comprehensive list of assessment themes and sub-themes for building refurbishment purposes. There 10 assessment schemes from various countries which are examined and compared: BREEAM, LEED, CASBEE, BEAM Plus, GBLS, Green Star, HQE, Green Mark, GBI and MyCrest. The findings reveal fourteen themes that are considered for assessment: management, sustainable site, transport, indoor environmental quality (IEQ), water, waste, material, energy, pollution, innovation, economy, society, culture and the quality of services. The results of the comparison show that energy and IEQ are dominant themes in all assessment schemes. Most schemes are considered relatively weak for evaluating economic and social aspects, in comparison to environmental aspects. The assessment of the quality of services is overlooked in most schemes, including GBI and MyCrest in Malaysia. Abdel Aleem et al. [4] presents a methodology, using the Analytic Hierarchy Process (AHP) for the assessment of the energy credits, by studying and comparing four of the common global rating systems: BREEAM, LEED, GS (Australian Green Stars), and the PEARL assessment system of the United Arab Emirates. The main goal of the presented research is to contribute to the enhancement of the GPRS (Egyptian Green Pyramid Rating System). According to the results, energy credits should be considered with their proposed weights for the present and future needs of a green Egypt. A comparison of two different rating systems, LEED (USA) and ITACA Protocol (Italy), is presented in another study [5]. The buildings presented in this study are both energy efficient and designed according to the principles of bioclimatic architecture, even if they are characterized by different features. The comparison shows that LEED pays more attention to the site choice and materials, while ITACA considers more energy and water management aspects. Indoor environmental quality is important in both LEED and ITACA for ensuring an adequate quality of confined spaces. The results show that the total score for LEED is “certified,” while that for ITACA is “B” in relation to both buildings. The points obtained are higher for the case study located in Orvieto (LEED 43, ITACA 61.94) than for the case study located in Foligno (LEED 41, ITACA 57.91), which shows that both methods assign scores in similar proportions. Another study [6] compares indicators and their levels from Estonian regulations against LEED and BREEAM requirements. The differences between the best practice requirements are shown, focusing on the indoor climate, energy and transport categories. Five technical design project documentations of recently built office buildings are assessed. To make the systematic comparison possible, Estonian building sustainability assessment scheme indicators are proposed, and their compliance with LEED and BREEAM is quantified. High indoor climate scores are found for all evaluated buildings. Furthermore, a Class A in the energy performance of a building shows close to the highest possible result in the energy category as well. Evaluated high performance buildings achieved the second highest certification level in LEED and BREEAM. The Class A with a high indoor climate quality achieved the highest certification level in LEED. The comparative evaluation reveals that Classes I and II can achieve the second highest certification levels in LEED and BREEAM. Class III achieves the third highest level in both schemes. To achieve the highest certification in LEED, a larger share of on-site renewable energy production is necessary; otherwise, improved public transport access and the number of available amenities are needed. In BREEAM, an enhanced performance in monitoring and public transport access is required. Rastogi et al. [7] investigated the potential changes in the energy performance resulting from applying different LEED versions (i.e., LEED v3 and v4) for the Energy and Atmosphere (EA) category. To this end, they carried out a case study on energy modeling and simulation, using TRACE 700, to compare the changes in the energy performance of four scenarios applied to an existing mid-rise multi-family building, located in Ohio, USA. The results showed notable changes in LEED. In particular, mid-rise multi-family buildings could benefit from LEED v4 in terms of LEED credits, as the prerequisite for the minimum energy performance improvement in the EA category has become significantly more lenient compared to LEED v3. On the contrary, when the percentage of energy performance improvement is over 34%, mid-rise multi-family buildings would benefit from LEED v3, as it becomes difficult to gain more points for similar energy performance improvement in LEED v4 compared to LEED v3. As shown in the case study, Scenarios 1 and 2 (i.e., renovation) achieved a value of 48.5% in energy performance improvement and received 30 points on average, whereas Scenarios 3 and 4 (i.e., new construction) could only achieve 14.4% in energy performance improvement and received 4.5 points on average. The goal of the research in study [8] is to evaluate the different ways of lowering the total environmental burden of a building’s life cycle, considering two building standards (wooden single-family residences, designed to meet the conventional Norwegian Building Code from 2010 (TEK10) and the Norwegian passive house standard NS3700). This paper evaluates the impacts of the implementation of renewable heating systems (resistance heating, wood, a solar heat collector, an air-water heat pump system), in comparison to standard Norwegian systems, which are largely based on electricity. The life cycle results show that the wood-framed single-family residence, built according to the passive house standard, provides a clear reduction in cumulative energy demand of 24–38%, in comparison to the conventional building standard TEK10 with electric panel heating. In combination with efficient heating systems, a passive house building envelope with a heat pump system provides the largest savings, an improvement of almost 40%, compared to a conventional house with electric heating. The reduction in greenhouse gas emissions of the cleanest design, compared to the standard alternative, is almost 30%. Solar heated water also provides substantial environmental gains for the passive house. On the other hand, a standard building envelope with a heat-pump system reduces impacts to a level comparable to that of a passive house building with only electric heating. Citherlet et al. [9] analyze and compare three variants of family houses in relation to the total environmental impacts produced during the whole building life cycle. The three variants have the same architectural aspect, but different insulation thicknesses and types, energy production systems and uses of different renewable energies. The calculation of the environmental impacts is carried out by means of a life cycle analysis, which includes, not only the impact related to the energy consumption during the occupancy stage, but also the manufacture, transport, replacement and elimination of the materials at the end of the building lifetime. This study has confirmed that good insulation provides a significant reduction of direct environmental impacts (energy consumption during the occupancy phase). Further the study has shown that, for a family house, it is important to consider the indirect impact of the total energy demand becoming lower than about 150 MJ/m²/y, for Swiss mix electricity production, and lower than about 50 MJ/m²/y for UCTmix (Union for the Co-ordination of Transmission of Electricity). When the energy demand is higher than these values, it is preferable to stress the reduction of direct impacts first, such as improving the envelope insulation or promoting the use of renewable energy sources. Zabalza et al. [10] presents the state-of-the-art application of the Life Cycle Assessment (LCA) in the building sector, providing a list of existing tools, drivers and barriers, potential users and purposes of LCA studies in this sector. It also proposes a simplified LCA methodology and applies this to a case study in Spain. Thermal simulation tools, considered in relation to the Spanish building energy certification standards, are analyzed and complemented with a simplified LCA methodology for evaluating the impact of certain improvements to the building design. Considering the life cycle in the energy certification process of the buildings allows for the promotion of sustainable buildings with a low energy consumption and high efficiency, favoring innovation in the construction sector. Therefore, in addition to promoting the use of renewable energy and equipment with a high energy efficiency, priority must be given to bioclimatic ecodesign and bioconstruction, the use of low impact, natural, recyclable materials available in the local area, the minimization of water consumption by designing rainwater collection systems and grey water networks in buildings, the design of green roofs, etc. An integrated LCAeLEED model, presented in study [11], incorporates LCA into LEED and assigns corresponding LEED scores to achieve a high level of sustainability assessment for the structure and envelope systems of Canadian school buildings. In this model, the selection of the most sustainable structure and envelope type for school buildings is conducted through the evaluation of three categories of the LEED rating system: energy and atmosphere, materials and resources, and LCA. Various options are tested by considering structures, such as concrete, steel, masonry and wood, and envelope types, such as precast panels, steel stud, wood stud and cavity wall. Energy simulation is performed by the eQUEST^® (version 3.64) program and LCA is performed by the ATHENA^® impact estimator. The results show that concrete and masonry buildings have a high energy consumption and global warming potential during certain life cycle stages, such as manufacturing, construction and demolition. However, they have a lower annual energy consumption and environmental impact during the operating stage, as well as for the overall life span. Concrete buildings with minimum insulation have obtained the highest total LEED score (19), followed by masonry (17), while steel and steel-masonry buildings have the lowest score (14). In study [12], the results of a research work dealing with energy and environmental assessments are presented. The samples considered were two “standard” wall compositions and two ventilated façades, using rock-wool and recycled Polyethylene Terephthalate (R-PET) as insulating materials. Finally, the study highlighted that the usage of recycled materials and easily disassembled compositions are cleaner construction solutions, which can be considered as key design choices for environmentally sustainable and low energy demanding buildings for their life cycles. According to study [13], building energy performance is considered the most important criterion in sustainability rating systems, and the lowest score is one in sustainability assessments. In contrast, other performance ratings of the building, such as water efficiency or indoor air quality, are achieved with a high rate of success in sustainability assessments. The results of certified buildings have shown that energy performances are well below the optimal ones, even in sustainable buildings. Reasons for this are often the high cost of energy saving measures and the low preparedness of construction actors. In contrast, indoor environmental quality, which is highly considered among criteria of sustainability rating systems, is generally reached at a high rate by sustainable buildings. In study [10], a simplified approach is proposed, which allows for global comparisons between the embodied energy and emissions of the building materials and the energy consumption and associated emissions during the use stage. The results show that embodied energy can represent more than 30% of the primary energy requirement during the life cycle of a single house of 222 m² with a garage for one car. The contribution of the building materials decreases if the house does not include a parking area, since this increases the heated surface percentage. Usually the top cause of energy consumption in a residential building is heating, but the second is the building materials, which can represent more than 60% of the heating consumption. Vilcekova et al. [14] points out that building structures consisting of natural materials exhibit low embodied energy values due to the fact that solar energy is used in the production of primary materials. In addition, plant materials largely conserve carbon within their mass and thus contribute to the elimination of global warming.

Uğur and Leblebici [15] present a cost-benefit analysis and payback period of two green buildings, located in Turkey. For the investigation, two buildings, in the gold and platinum categories according to the LEED certification system, were selected to present the actual expenses caused by greening. The additional construction cost was found to be 7.43% and 9.43%, the share of soft cost in the total construction cost was 0.84% and 1.31%, the reduction in the annual energy consumption cost was determined to be 31% and 40%, and the payback period of the additional construction cost was calculated to be 0.41 and 2.56.

One of the possibilities for reducing the negative impacts on the environment, which immediately provides a healthier surrounding and internal environment, is to design and construct buildings respecting sustainability pillars. Therefore, the main goal of this paper is to present the current trend in the design and construction of family houses in Slovakia and to identify gaps in key sustainability aspects of design and construction through the Slovak building environmental assessment system [16]. Three family houses were chosen for the detailed investigation of categories aimed at site selection and project planning, building constructions, indoor environment, energy performance, water and waste management. The evaluated houses reached the relevant scores in each main field, followed by an overall rating and classification to an appropriate scale. Such comprehensive assessment can lead to obtaining valuable information about the object, technical and functional characteristics, environmental impacts, social and economic performance, resulting in optimization measures.

2. Materials and Methods

2.1. Low-Rise Residential Family Houses

Three new family houses, located in the northwestern part of the town of Kosice in the Slovak Republic were selected for the investigation. Some requirements have been taken into account for the selection of family houses. Firstly, they are to be built in low-rise residential areas according to urban zoning plans. The location of buildings is not to be in the floodplain town of Kosice [17]. In order to obtain comparable results from the assessment by building environmental assessment system (BEAS), it was necessary to choose similar family houses to meet requirements such as the size of the object, thermo-physical characteristics, material compositions, building technology, occupancy, years of the construction, environment pollution, etc.

The territory, where family houses are situated, is a strongly disturbed environment, according to the Environmental regionalization of Slovakia [18]. Family House 1 is located in an area that was originally used for gardening purposes, near the forest, with a slightly sloping terrain. Family House 2 is located on a slightly sloping terrain in a densely built-up area, with cramped conditions for further construction, and Family House 3 is located on a sloping terrain in a slightly built-up area. The locations of the three family houses are depicted in Figure 1.

Assessed family houses were chosen so as to ensure the compatibility of the urban design with local cultural values. Family houses are designed according to requirements of laws and standards of the EU and Slovak republic. These houses are occupied approximately for 3 years from the end of the construction. Detailed information about houses is presented in

Table 1. Design and construction of evaluated family houses.

Figure of Family Houses—Photo/Floor Plan of the First Floor
Family House 1	Family House 2	Family House 3
Built-up area, Useful floor area, Built-up volume, Number of storey’s
111.0 m2; 211.5 m2; 613.4 m3; two-story building without basement	296.0 m2; 278.2 m2; 1185.6 m3; single-story building with basement	248.5 m2; 445.1 m2; 1693.7 m3; two-story building with basement
Foundations
reinforced concrete foundation strip	reinforced concrete foundation strip	reinforced concrete foundation strip
External walls, surface finishes
aerated concrete blocks (Ytong Lambda) with a thickness of 375 mm; external plaster	ceramic blocks (Porotherm), combined with reinforced concrete walls with a thickness of 250–300 mm; silicate exterior plaster, combined with stone cladding	sheeting concrete blocks, combined with Porotherm blocks with a thickness of 300 mm; silicate exterior plaster, combined with aluminum composite wall panels
Ceiling structures
reinforced concrete slabs with a thickness of 200 mm	reinforced concrete slabs with a thickness of 200 mm	reinforced concrete slabs with a thickness of 200 mm
Roof construction, roof covering
saddle roof, wood structure, lightweight asphalt-board	flat roof, reinforced concrete slabs, extensive and intensive vegetation roof	flat roof, reinforced concrete slabs, two-layer waterproofing modified belts
Interior walls, surface finishes of walls
gypsum plasterboard with a thickness of 150 mm, lime plasters and ceramic tiles	sandwich constructions from plasterboard and thermal insulation from mineral wool with a thickness of 150 mm, gypsum plasters and ceramic tiles	Porotherm blocks with a thickness of 150 mm, gypsum plasters and ceramic tiles
Floor and ceiling surface finishes
floors—wooden floor, ceramic tiles, linoleum, ceilings—gypsum plasters, plasterboard	floors—wooden floor, ceramic tiles, linoleum, concrete paving, ceilings—plasterboard, architectural concrete	floors—wooden floor, ceramic tiles, PVC, concrete floor, ceilings—gypsum plasters, plasterboard
Insulations of ground floor, external walls and roof
ground floor—waterproofing PVC, polystyrene with a thickness of 100 mm, external walls—without insulation, roof—mineral wool with a thickness of 300 mm	ground floor—2× geotextile, waterproofing PVC, expanded polystyrene with a thickness of 350 mm, external walls—mineral wool thickness 200 mm, roof—expanded polystyrene with a thickness of 200 mm, waterproofing PVC, protective fabrics of artificial fibers, drainage foil, filtration textile	ground floor—3× geotextile, waterproofing PVC, extruded polystyrene with a thickness of 120 mm, external walls—mineral wool with a thickness of 250 mm, roof—2× geotextile, extruded polystyrene with a thickness of 200 mm
Windows
Plastic windows (Fenestra) with triple glazing (Ug = 0.6 W/m2K) and horizontal plastic interior blinds	aluminum windows (SCHUCO) with triple glazing (Ug = 0.6 W/m2K) and horizontal aluminum exterior blinds	aluminum windows (Aliplast) with triple glazing (Thermoglass) (Ug = 0.7 W/m2K) and horizontal aluminum exterior blinds
Heating or cooling, ventilation
electric heating by low temperature radiant ceiling panels (Ecosun), hot water fireplace (ABX-Stockholm), natural ventilation	floor and ceiling heating by heat pump type earth-water (IVT PremiumLine), fireplace, ceiling cooling—dry system (REHAU), natural ventilation	floor heating and radiator by gas boiler with additional solar systems, fireplace (Bruner), heat and ventilation recovery units (Atrea Duplex)
Connection to engineering networks
electrical and water connection, cesspool	electrical, sewage and water connection	electrical, gas, sewage and water connection

. Selected family houses were evaluated by the building environmental assessment system (BEAS), developed for Slovak conditions. BEAS has been developed at the Institute of Environmental Engineering at the Technical University of Kosice. The main fields and indicators of building environmental assessment were proposed on the basis of available information analysis in relation to particular fields of building performance, European and Slovak standards and our experiences. BEAS contains 6 main fields: A—Site Selection and Project Planning; B—Building Construction; C—Indoor Environment; D—Energy Performance; E—Water Management and F—Waste Management, see

Table 2. Main fields, subfields and indicators, according to building environmental assessment system (BEAS).

Fields	Subfields and Indicators
A	A1—Selection of location for the construction; A2—Selection of location vulnerable to flooding; A3—Selection of location nearby recipient; A4—Selection of Brownfield areas; A5—Distance of construction site to road-traffic infrastructure; A6—Distance to commercial and cultural facilities; A7—Distance to sport and active recreation; A8—Distance to public or natural green space; A9—Possibility of connection to engineering networks; A10—Possibilities exploitation of renewable energy sources; A11—Possibility to maximize passive solar gains by the orientation of the building; A12—Compatibility of the urban design with local cultural values; A13—The occurrence of transport infrastructure in the construction site; A14—The share of green spaces in the construction site
B	B1 Materials: B1.1—Product environmental labeling; B1.2—Use of local materials; B1.3—Use of recycled materials; B1.4—Use of substitutes in concrete; B1.5—Radioactivity of building materials; B2—Life cycle of materials: B2.1—Primary energy embodied in building materials; B2.2—Global warming potential; B2.3—Acidification potential
C	C1—Thermal comfort during the heating season; C2—Thermal comfort during the cooling season; C3—Natural ventilation and mechanical ventilation; C4—Noise attenuation through the exterior envelope; C5—Noise isolation between primary occupancy areas; C6—Daylighting; C7—Shading and blinds; C8—Artificial lighting; C9—The materials used in the building; C10—Transfer of pollutants from the garage space into the user space of the house
D	D1—Operation energy: D1.1—Energy for heating; D1.2—Energy for domestic hot water; D1.3—Energy for mechanical ventilation and cooling; D1.4—Energy for lighting; D1.5—Energy for appliances; D2—Active systems using renewable energy sources: D2.1—Solar system/heat pump; D2.2—Photovoltaic technology; D2.3—Heat recuperation; D3—Energy management: D3.1—System of energy management
E	E1—Reduction and regulation of water flow in water systems; E2—The water management of surface runoff; E3—Drinking water supply; E4—System of grey water
F	F1—Plan of waste disposal originating in the construction process; F2—Measures to minimize waste resulting from building operation; F3—Measures to minimize emissions resulting from air pollution sources

. Some of the main fields are divided into subfields with indicators. Each indicator is assigned a certain weight of significance and evaluative scales (−1 negative, 0 acceptable, 3 good, 5 best). Each indicator is defined by the purpose of evaluation and by a criterion, according to which the assessment is made. After the assessment, the building is certified according to the scale presented in

Table 3. Assessment scale [16].

	Key for Assessment	Certification Scale
−1	unacceptable building	Unacceptable building
0	acceptable building	BEAS CERTIFIED
0–1.5	acceptable building	BEAS BRONZE
1.5–3	good building	BEAS SILVER
3–4	better building	BEAS GOLD
4–5	best building	BEAS PLATINUM

[16].

2.2. Methodology

Before the assessment was made, it was necessary to choose new family houses, to consider in terms of their location and comparability, and to collect project documentation on architecture, building constructions, ventilation, heating and cooling, hot water preparation, building energy efficiency report, etc. On the basis of the collected draws, technical specifications, documents and reports, the basic information and characteristics of the houses, constructions, HVAC systems, information about the uses of renewable energy systems, the amount of built-in building materials (for example for LCA), etc., were processed.

A subsequent analysis, calculation of parameters, documentation of the facts necessary for the assessment and assignment of scores according to requirements and the methods of each indicator evaluation have been carried out.

The assessment itself was conducted using a Microsoft Excel tool, in which each main field (A–F) is processed in a separate sheet, with a key for the rating and certification scale. For each field, the evaluation method of all indicators, allocation of points and calculation based on the percentage weight of significance of each indicator is processed in each sheet. The results are presented in the last evaluative list in the form of column graphs and total tables. Detailed information about the BEAS tool can be seen in [16].

Thus, each family house considered was evaluated and awarded a level of certification. Finally, these houses were compared and analyzed in terms of their strengths and weaknesses in the results.

3. Results and Discussion

3.1. Site Selection and Project Planning

The integration of the buildings into the landscape is important in terms of minimizing the impact on natural resources and the surrounding natural habitat, ensuring the user’s comfort and the compatibility of the urban design with local values. Assessed family houses are located in the eastern part of Kosice in the Slovak Republic. The environmental regionalization of the country represents a source of information about the state of the environment and reflects various states of the environment in different parts of the country [18]. According to the Report of the State of the Environment in 2015 [18], the territory of Kosice belongs to the areas with a strongly disturbed environment. Criteria for the evaluated indicators in field A—Site Selection and Project Planning—are presented in

Table 4. Criteria for the evaluated indicators in field A.

Indicator	Criteria
A1	Class of environmental level: from heavily deteriorated to a high level of environment
A2	Place of construction outside the flood territory: minimum peak elevation of construction site over 100 years of water is between 1 m and 25 m
A3	Distance from the construction site to the recipient: <15 m to >75 m
A4	Brownfield Revitalization: construction on a Greenfield/Brownfield
A5	Distance from the building to the road-traffic infrastructure: >500 m to <100 m
A6	Distance from the building to the commercial and cultural facilities: >1000 m to <500 m
A7	Distance from the building to sport and active recreation: >1000 m to <500 m
A8	Distance to the public or natural green space: >1000 m to <500 m
A9	Possibility of connection to public construction sites: there is no possibility of connection to engineering networks; there is a possibility of connection to engineering networks, such as water and sewage connections, as well as electricity and gas connections
A10	Potential of the construction site exploitation of renewable energy sources: there are no possibilities for exploitation; there is a possibility to use up to three systems using renewable energy sources
A11	Percentage area of the building oriented east—west: 40–100%
A12	Assessment of the building status with local cultural values relating to design and architecture, including functional and aesthetic aspects: the architectural design does not respect the existing cultural values in relation to urban design and architecture—a prime example of compatibility with cultural values relating to urban design and architecture
A13	Assessment of the construction site in view of the occurrence of the transport network in the given settlement structure: occurrence of significant transport infrastructure (highway, road of 1st, 2nd or 3rd class and local or tertiary roads)
A14	To ensure the minimum percentage of green areas for the construction of family houses: minimum percentage of green spaces of the total land area <60% to >75%

. In

Table 5. Results of the assessment of family houses in field A.

	Family House 1	Family House 2	Family House 3
	Score
A1	−1	−1	−1
	territory with strongly disturbed environment	territory with strongly disturbed environment	territory with strongly disturbed environment
A2	5	5	5
	no flood territory	no flood territory	no flood territory
A3	3	5	5
	48 m	120 m	>75 m
A4	3	3	3
	outside the brownfield area	outside the brownfield area	outside the brownfield area
A5	−1	−1	0
	616 m	750 m	500 m
A6	−1	−1	−1
	>1000 m	>1000 m	>1000 m
A7	−1	−1	0
	>1000 m	>1000 m	<1000 m
A8	5	5	5
	<500 m	<500 m	<500 m
A9	0	5	5
	possibility of connection to water connection, as well as electricity connection	possibility of connection to water and sewage connections, as well as electricity and gas connections	possibility of connection to water and sewage connections, as well as electricity and gas connections
A10	3	5	5
	possibility to use two systems using renewable energy sources (photovoltaic panels, heat pumps)	possibility to use three systems using renewable energy sources (solar panels, photovoltaic panels, heat pumps)	possibility to use three renewable energy sources (solar panels, photovoltaic panels, heat pumps)
A11	−1	0	0
	41.8%	60.1%	51.5%
A12	3	3	3
	fully respects	fully respects	fully respects
A13	5	5	5
	local and tertiary roads	local and tertiary roads	local and tertiary roads
A14	5	−1	−1
	79.52%	37.04%	52.51%

we can see the results of the evaluated family houses in field A.

Based on the assessment of individual indicators in field A–Site Selection and Project Planning–all family houses achieved the highest score of 5 for the following indicators: selection of location vulnerable to flooding, distance to public or natural green space and the occurrence of transport infrastructure in the construction site. Indicators related to the selection of the location nearby the recipient, possibility of connection to engineering networks and possibilities for the exploitation of renewable energy sources for Family Houses 2 and 3 also achieved a score of 5. Family House 1 obtained the highest score for the share of green spaces in the construction site. It can be stated that all family houses are not located in the flood territory, building sites are located nearby natural green spaces up to 500 m, and there is no significant transport infrastructure. Family Houses 2 and 3 are not located nearby the potential recipient, the sites of buildings have the possibility of connection to engineering networks, such as water and sewage connections, as well as electricity and gas connections, and they have the possibility to use three systems using renewable energy sources (solar panels, photovoltaic panels, heat pumps). The location of Family House 1 can be characterized as a natural environment, with the highest share of green spaces (79.52%), compared to Family Houses 2 and 3. A score of 3 was achieved for the indicator concerning the selection of brownfield areas and the compatibility of the urban design with local cultural values in all family houses. The selection of the location nearby the recipient and the possibilities for the exploitation of renewable energy sources were obtained, with a score of 3, for Family House 1. The architectural design of all evaluated family houses fully respects the existing cultural values relating to urban design and architecture. A score of 0 was achieved for the following indicators: distance from the construction site to road-traffic infrastructure, distance to sport and active recreation for Family House 3; possibility of connection to engineering networks for Family House 1; and the possibility to maximize passive solar gains by the orientation of building for Family Houses 2 and 3. A score of −1 was achieved for indicators related to the selection of the location of the construction, distance to the commercial and cultural facilities for all family houses; distance from the construction site to road-traffic infrastructure; the distance to sport and active recreation for Family Houses 1 and 2; the possibility to maximize passive solar gains by the orientation of the building for Family House 1; and the share of green spaces in the construction site for Family Houses 2 and 3. Based on the evaluation, it can be stated that Family House 3 obtained the best rating of 2.32, Family House 2 achieved a score of 2.18, and Family House 1 achieved the lowest score of 2.0, see Table 16.

An assessment of building sustainability, which would be tailored to different regions of the country and whose specificity takes into account the main interests of the country, is presented in the study [19]. This is an evaluation strategy, developed for the sustainable development of buildings in Algeria. In light of the results of the study, the environmental approach for sustainable buildings in Algeria is flexible and easily adaptable to different regions according to their physical characteristics, as well as the geographic, climatic and socio-cultural practices that characterize their populations. The evaluation takes into account the major concerns of the country, such as the rebalancing of the urban structure, energy performance, and water and waste management. However, the utmost importance is given to the choice of the construction implantation site to ensure good land management. Strengthening the existing national legislative and regulatory framework through the implementation of legislation and regulations as well as the establishment of control and monitoring is recommended. Developing the exploitation of solar energy, especially in the southern part of the country, where the solar thermal potential, photovoltaic and wind power is the highest in the country, is also suggested. According to another study [20], it is important to assess the impact of the ecological footprint (EF) of the reconstruction of the building versus the building demolition and new construction. The study analyzes the impacts of numerous changes, such as materials through their replacement with materials that generate less environmental impact or through the analysis of solutions to raise the level of energy improvement in the building façade or rooftop, and the incorporation of air-conditioning installations of a more efficient nature. From this analysis, it can be concluded that the actions performed in relation to energy improvement reduce both the economic and environmental impact to 66% of that of the initial state. The analysis of the partial EFs of rehabilitation reveals that the embodied energy of the manufacturing, transport and installation of the materials used in this process cause 82.93% of the total EF. Cement (41.14%) and steel (17.71%) particularly stand out in terms of CO₂ emissions due to the execution of the underpinning foundation. From the comparison of the results of rehabilitation with those of demolition and new construction, it is concluded that the TPC of rehabilitation is 21.31% lower than the budget of demolition and new construction. On the other hand, the environmental impact in terms of EF is 58% and 68% lower (depending on the CTE DB-HE applied) in the case of rehabilitation.

3.2. Building Construction

The quality of the built environment also affects its inhabitants in many ways and is dependent, not only on the architectural form and specification, but also on the quality and nature of the materials used. Environmentally friendly building materials and structures reduce energy and material flows during the entire building life cycle. Criteria for the evaluated indicators in BEAS for field B—Building Construction—can be seen in

Table 6. Criteria for the evaluated indicators in field B.

Indicator	Criteria
B1–B1.1	The environmental use of appropriate construction products: percentage share of the built-in product <0% until >50%
B1.2	Distance of manufacturing materials from the construction site: >500 km to <100 km
B1.3	Minimum required recyclable share in the built-in building material: recyclable share in the built-in materials <20% to >50%
B1.4	Recommendation to replace cement with concrete: percentage weight of the replaced cement compared with concrete <20% to >50%
B1.5	Limitation of the use of materials containing natural radionuclides: mass 226Ra activity in the construction products >120 Bq/kg to <100 Bq/kg
B2–B2.1	Primary energy consumption: primary energy embodied in the building materials >1500 MJ/m2 to <600 MJ/m2
B2.2	The amount of CO2 emissions from non-renewable sources: global warming potential >100 kg/m2 to <10 kg/m2
B2.3	The amount of SO2 emissions from non-renewable sources: acidification potential >0.45 kg/m2 to <0.25 kg/m2

, and the results are presented in

Table 7. Results of the assessment of family houses in field B.

	Family House 1	Family House 2	Family House 3
	Score
B1.1	−1	0	−1
	no built-in product with an environmental label	built-in product with an environmental label (Eco friendly)—over 10%	built-in product with an environmental label (FSC certification)—to 10%
B1.2	0	0	0
	250–500 km	250–500 km	250–500 km
B1.3	−1	5	5
	no use of recycled materials	>50%	>50%
B1.4	−1	−1	−1
	<20%	<20%	<20%
B1.5	5	5	5
	<100 Bq/kg	<100 Bq/kg	<100 Bq/kg
B2.1	−1	−1	−1
	3787.9 MJ/m2	6695.4 MJ/m2	5157.8 MJ/m2
B2.2	−1	−1	−1
	286.9 kg/m2	473.4 kg/m2	374.6 kg/m2
B2.3	−1	−1	−1
	1.30 kg/m2	2.18 kg/m2	1.64 kg/m2

.

The environmental performance of the material solutions for each building is calculated by using the method of LCA within the boundary, “cradle to gate”. The analysis investigates the building material compositions in terms of the embodied energy (EE) from non-renewable resources and emissions of CO₂ [ECO2, global warming potential (GWP)] and SO₂ [ESO2, acidification potential (AP)] in the evaluated houses. The input data of the aforementioned environmental indicators are extracted from the Austrian LCA database—IBO Ecological Construction Component Catalog [21].

Based on the assessment of the building materials used in constructions, we can summarize the results in the following graphs, see Figure 2, Figure 3 and Figure 4.

Embodied energy is expressed as the total value of the embodied energy per useful floor area of the building in MJ/m². The values of EE are determined to be 3787.87 MJ/m², 6695.38 MJ/m² and 5157.8 MJ/m² for Family Houses 1, 2 and 3, respectively.

The results of the GWP for each of the building structures of the rated family houses are represented in Figure 3. The total GWP, expressed as CO_2eq, are determined to be 286.9 kg/m² per year, 473.4 kg/m² per year and 374.60 kg/m² per year for Family Houses 1, 2 and 3, respectively.

The results of the AP, expressed as SO_2eq, are represented in Figure 4. The equivalent amount of SO₂ emissions from non-renewable sources is 1.30 kg/m² per year, 2.18 kg/m² per year and 1.64 kg/m² per year for Family Houses 1, 2 and 3, respectively.

Based on the overall assessment of the indicators in field B—Building Construction—the highest score (5) was achieved for the indicators evaluating the radioactivity of the building materials for all family houses and the use of recycled materials for Family Houses 2 and 3. The declared mass activity of ²²⁶Ra of the construction products and materials used in the construction of the family houses does not exceed 100 Bq/kg. Family Houses 2 and 3 have built-in construction products, whose recyclable share in building materials is more than the 50% (for example, building materials used as intensive vegetation roofs, with recyclable HDPE and artificial fibers or an exterior wood floor). A score of 3 was not assigned to any of the indicators for the evaluated family houses. A score of 0 was achieved for the indicators concerning the use of local materials for all family houses and product environmental labeling for Family House 2. The distance of the manufacturing materials from the construction site of the evaluated family houses is a distance in the range of 250–500 km for all family houses. In Family House 2, there are built-in construction products, which have been awarded the environmental label, Eco friendly (interior finishing floors are designed with wood floor; window structures are designed with aluminum, with a multi-chamber system by Schüco) or FSC certification (exterior wood flooring), with a percentage share of 10%. A score of −1 was achieved for the indicators evaluating the use of concrete substitutes, embodied energy, global warming potential, and acidification potential for all family houses. The indicator concerning product environmental labeling achieved a score of −1 for Family Houses 1 and 3, and the indicator concerning the use of recycled materials achieved a score of –1 for Family House 1. The use of cement refills in concrete applied in evaluated buildings does not represent even a 20% share of the weight of the cement replaced with concrete. The indicator life cycle assessment of materials was found to be negative for all family houses. The energy embodied in the building materials of all assessed family houses is more than 1500 MJ/m², the global warming potential is more than 100 kg/m², and the acidification potential is more than 0.45 kg/m². The largest embodied energy consumption in MJ per useful floor area of buildings belongs to the bearing walls, foundations, ceilings, roof and floors in Family Houses 2 and 3, and the smallest consumption was in Family House 1. Similarly, the highest values for global warming potential and acidification potential are achieved in Family Houses 2 and 3 in relation to the bearing walls, foundations, ceilings, roofs and floors, and the smallest values are achieved in Family House 1. The values for embodied energy, global warming potential and acidification potential in evaluating the buildings did not reach the benchmark for a positive rating. Higher values of EE, GWP and AP have been achieved because the building structures are designed with reinforced concrete foundation strips and sheeting concrete blocks, combined with Porotherm blocks and ceramic blocks (Porotherm), with reinforced concrete walls. Those materials negatively affect the life cycle assessment of building materials. The lowest score was assigned to indicators related to the products’ environmental labeling and the use of recycled materials for Family House 1. This family house does not have built-in products with environmental labels and recycled materials. Based on the overall evaluation it can be stated that Family House 2 obtained the best rating of 0.47, Family House 3 achieved a rating of 0.36, and Family House 1 achieved a rating of −0.28, as shown in Table 16. Family Houses 2 and 3 have achieved approximately the same ratings, but better ratings than Family House 1. The building materials for Houses 2 and 3 meet the minimum requirement of recyclable share in built-in building materials and contain more than 50% recycled materials. These houses also have built-in products and materials with environmental labels. A lot of other studies are focused on the environmental evaluation of building materials and constructions. For example, study [22] shows that the environmental impact of a building is largely influenced by the material choices made at the early design stage of the project. To determine the embodied energy and environmental impacts of building materials, the Dutch have developed an assessment method, which has also been adapted by BREEAM-NL. This method is applied to a case study of a new office building in Central Netherlands for evaluating the environmental impact of the construction materials. The environmental impacts of the materials used in the preliminary design of the case study are found to be 35% below the reference value. Not only the building sections and components with the largest contributions to the environmental impacts have been identified, but the selection and use of alternate building materials to improve the environmental performance of the case study of the building have also been exhibited. It has been shown that it is possible to reduce the environmental impacts of building materials, even in the case of a carefully-designed low energy building (the environmental impacts of materials for the case study buildings have been lowered by over 50% of the reference value). In study [23], a life cycle assessment model, namely, the Environmental Model of Construction (EMoC), is developed and presented in order to help decision-makers assess the environmental performance of building construction projects in Hong Kong, from the cradle to the end of construction. The model provides comprehensive analyses of 18 environmental impact categories at the midpoint and endpoint levels. A public rental housing (PRH) project is fed into EMoC to examine the environmental performance of this type of project. The results indicate that the material is the major contributor to the environmental impacts of the upstream stages of public housing construction. The carbon emissions of the studied project amount to 637 kg carbon dioxide equivalent per square meter of the gross floor area. Sensitivity analysis reveals that environmental pollution can be significantly reduced by adopting a higher proportion of precast concrete components. Rincón et al. [24] also proves that the sustainability of building construction systems depends on their material and energy consumption and the consequent environmental impact. In this study, the environmental impacts of different construction systems of the building envelope have been evaluated by means of two complementary methodologies, Material Flow Analysis (MFA) and Life Cycle Assessment (LCA). MFA and LCA used together can offer a full environmental evaluation. For this reason, in this study, five different façade constructive systems are evaluated with MFA and LCA to compare them from an environmental point of view. The MFA results show the significant quantity of natural resource extraction required for building, which leads to a considerable ecological rucksack. On the other hand, the LCA results show the importance of the operational phase of the building in the overall building energy consumption, and therefore in the environmental impact.

3.3. Indoor Environment

In recent years, monitoring of the indoor environmental quality has indicated that the air within buildings can be more seriously polluted than the outdoor air. The factors that comprise IEQ can be classified as chemical, physical, and biological. The sensory systems of the inhabitants interact directly with some factors, such as sound level, light, odor, temperature, humidity, electrostatic charges, and other irritants. Monitoring of the indoor environmental quality is very important and evaluated within the comprehensive assessment of buildings. Criteria and results for the evaluated indicators in field C—Indoor Environment—can be seen in

Table 8. Criteria for the evaluated indicators in field C.

Indicator	Criteria
C1	Design value of operative temperature according to EN 15251: 2007: operative temperature in 95% of buildings during the heating season (θo < 18 °C to θo ≥ 21 °C)
C2	Design value of operative temperature according to EN 15251: 2007: operative temperature during the cooling season does not meet the requirements—meets the requirements
C3	Natural ventilation: The total area of the openings in the exterior envelope is at least 5% of the total floor area, and at least 50% of the space has ventilation from the top down—the total area of the openings in the exterior envelope is at least 10% of the total floor area, and more than 90% of the space has ventilation from the top down. Mechanical ventilation: design requirements of the STN EN 15251: 2007: does not meet the minimum requirements—exceeds the minimum requirements.
C4	Noise attenuation through the exterior envelope in residential areas of cities according to Slovak standard STN 73 0532. (Quality class of sound insulation <2 to ≥4)
C5	Noise attenuation between the rooms of the building: airborne sound insulation does not meet the minimum requirements—exceeds the minimum requirements according to STN 73 0532
C6	Daylight factor according to STN 73 0580: does not reach the minimum values for the scheduled tasks—reaches minimum values for the scheduled tasks
C7	Design shielding measures to prevent glare in interior spaces: no designed shielding elements—the most appropriate shielding elements are designed
C8	The level and quality of lux illuminance for the scheduled tasks: inappropriate level and quality of lux illuminance for the scheduled tasks—high level quality of lux illuminance for the scheduled tasks
C9	The choice of materials with low or no release of TVOC emission intensity: no selected materials with a low release of TVOC emission intensity—materials with no release of TVOC emission intensity
C10	Isolated space or rooms in which pollutants can be produced: The built-in garage is not ventilated nor functionally connected with the indoor spaces—garage outside the building, built-in garage is ventilated and functionally connected with indoor spaces with a CO2 sensor

and

Table 9. Results of the assessment of family houses in field C.

	Family House 1	Family House 2	Family House 3
	Scales of Evaluating
C1	0	0	0
	18 ≤ θo < 20 °C	18 ≤ θo < 20 °C	18 ≤ θo < 20 °C
C2	−1	0	0
	does not use cooling system	fulfilled the minimum requirements	fulfilled the minimum requirements
C3	5	5	5
	Natural ventilation: at least 10% of the total floor area and more than 90% of the ventilation space from the top down	Natural ventilation: at least 10% of the total floor area and more than 90% of the ventilation space from the top down	Mechanical ventilation in 100% of the space exceeds the minimum requirements
C4	5	5	5
	4	4	4
C5	0	3	3
	fulfilled the minimum requirements of the standard	exceeded the minimum requirements of the standard	exceeded the minimum requirements of the standard
C6	5	5	5
	fulfilled minimum values	fulfilled minimum values	fulfilled minimum values
C7	5	5	5
	the most appropriate shielding elements designed	the most appropriate shielding elements designed	the most appropriate shielding elements designed
C8	5	5	5
	high level quality of lux illuminance	high level quality of lux illuminance	high level quality of lux illuminance
C9	0	0	0
	materials with a low-level release of TVOC emission intensity selected	materials with a low-level release of TVOC emission intensity selected	materials with a low-level release of TVOC emission intensity selected
C10	5	0	0
	garage outside the building	built-in garage is ventilated and functionally connected with indoor spaces, with the required door panel	built-in garage is ventilated and functionally connected with indoor spaces, with the required door panel

.

Based on the overall assessment of the indicators in field C—Indoor Environment—the highest score (5) was assigned to Family Houses 1, 2 and 3 for indicators that rated the area and location of the windows in relation to their capacity to provide natural ventilation, noise attenuation through the exterior envelope in the residential areas of cities according to Slovak standard STN 73 0532, a daylight factor defined in STN 73 0580, design shielding measures to prevent glare in interior spaces and the level and quality of illuminance for the scheduled tasks. The total area of the openings in the exterior envelope is at least 10% of the total floor area and more than 90% of the ventilation from the top to down. Family House 3 is equipped with mechanical ventilation, meaning that 100% of the space exceeds the minimum requirements according to EN 15251: 2007. The quality class of sound insulation for windows in the exterior envelope of the evaluated family houses is 4, according to STN 73 0532. A daylighting factor of 100% for the space is at least as high as the value of the planned tasks for all family houses, according to requirements of the standard. The artificial lighting of family houses is sufficient for the task for every 10 m² of occupied area. A score of 3 was achieved for the indicators that rated noise attenuation in the rooms of Family Houses 2 and 3. The airborne sound insulation exceeds the minimum requirements of the standard. A score of 0 was achieved for the indicators that rated the operative temperature in 95 % of the buildings during the heating season (θo < 18 °C–θo ≥ 21 °C) for Family Houses 1, 2 and 3 as well as the operative temperature during the cooling season (requirements according to EN 15251: 2007) for Family Houses 2 and 3. This score was assigned to the indicator that rated the choice of materials with little or no release of TVOC emissions, namely, in Family Houses 1, 2 and 3, and the indicator that rated the isolated space or rooms in which pollutants can be produced achieved the same score in Family Houses 2 and 3. Evaluated family houses meet the requirements of Slovak standards for the operative temperature in the heating and cooling season and for mechanical ventilation. More than 75% of interior materials (including paints, sealants, adhesives, carpets and composite wood products) are chosen as materials, with low emissions of VOC, and wood products containing urea formaldehyde resins are not used. The airborne sound insulation of Family House 1 meets the minimum requirements of the standard. A score of −1 was achieved for the indicator that rated the operative temperature during the cooling season for Family House 1, because a cooling system is not used. The results show that Family House 3 obtained the best rate of 2.80, Family House 1 achieved a rate of 2.40, and Family House 2 obtained a rate of 2.30, see Table 16. The rated houses achieved approximately the same rating, with small differences in the obtained values. All houses are designed according to the requirements of the Slovak legislation and slightly exceed the minimum standards for indoor environments. Smaller differences in values are caused by the evaluation of House 1. The reason for the lowest obtained values, obtained by Family House 1, is that a cooling system is not used and, therefore, the operative temperature during the cooling season does not meet the requirements. The indoor environmental quality investigated within the sustainability assessment of the buildings is an important issue, which is also discussed in other studies. The objective impact of green buildings on health, IEQ, self-reported health, and heart rate in 30 participants living in green and conventional buildings for two weeks is investigated in study [25]. In this study, 24 participants were selected to be relocated to the Syracuse Center of Excellence, a LEED platinum building, for six workdays. While they were there, ventilation, CO₂, and volatile organic compound (VOC) levels were changed on different days to match the IEQ of conventional, green, and green+ (green, with increased ventilation) buildings. Participants reported an improved air quality, odors, thermal comfort, ergonomics, noise and lighting and fewer health symptoms in green buildings prior to relocation. After relocation, participants consistently reported fewer symptoms in the green building conditions, compared to the conventional one, yet symptom counts were more closely associated with environmental perceptions than with measured IEQ. These findings suggest that the occupant health in green and conventional buildings is driven by both environmental perceptions and physiological pathways. The study in [26] is focused on microclimatic simulation, which is an important tool for predicting air flow, surface temperature heat transfer, providing valuable information in case of retrofitting the area under investigation to reduce the energy footprint. The importance of coupling the external and internal environment is presented. The microclimatic condition of the area under investigation can lead to a difference of ±10% in power for heating/cooling needs when the local microclimatic conditions replace the weather file used by the BES software. If the exchange of data between the two domains includes the exchange of the CHTC, the difference in heating/cooling needs can be as high as ±40%. A novel method has been developed for the indirect coupling of building energy simulation and microclimatic software. Further research needs to be carried out analyzing the impact of the external CHTC for different climate conditions and locations.

3.4. Energy Performance

The goal of energy performance is to reduce the total building energy consumption, air pollution, global warming and ozone depletion caused by energy production. The choice of indoor design conditions affects indoor temperature, ventilation rate, lighting and equipment power, which can substantially influence the energy demand in a building. Therefore, energy performance is one of the most important aspects of the sustainability assessment. Field D—Energy Performance—in BEAS is introduced in

Table 10. Criteria for evaluation in field D.

Indicator	Criteria
D1.1	Class of energy for heating according to the Law No. 555/2005 of the energy performance of buildings: from an energy class lower than C to energy class A
D1.2	Class of energy for domestic hot water according to the Law No. 555/2005 of the energy performance of buildings: from an energy class lower than C to energy class A
D1.3	Building uses a mechanical ventilation system or cooling system: there is no ventilation or cooling—ventilation ensured by air conditioning
D1.4	Energy demand for lighting in family houses is not rated according to Slovak standards.
D1.5	Electrical appliances with low energy consumption expressed as energy class: at least one appliance is in an energy class less than B—all appliances are in energy class A
D2.1	Using solar system/heat pump for heating and hot water: no use of solar system/heat pump—solar system/heat pump covers more than 75% of energy consumption
D2.2	Photovoltaic technology: no photovoltaic technology used—photovoltaic technology covers more than 60% of energy consumption
D2.3	Heat recuperation: no heat recuperation used—heat recuperation uses more than 75% of waste heat
D3.1	Monitoring of operation and maintenance of building services: there is no energy management system—energy management system is established

and the results, in

Table 11. Results of the assessment of family houses in field D.

	Family House 1	Family House 2	Family House 3
	Score
D1.1	5	5	5
	A	A	A
D1.2	3	5	5
	B	A	A
D1.3	−1	0	5
	no mechanical ventilation system used	no mechanical ventilation system used but cooling system used	mechanical ventilation system with air treatment
D1.4	0	0	0
	-	-	-
D1.5	5	5	5
	A	A	A
D2.1	−1	5	5
	no renewable energy sources used	heat pump	solar system
D2.2	−1	−1	−1
	no photovoltaic technology used	no photovoltaic technology used	no photovoltaic technology used
D2.3	−1	−1	5
	no heat recuperation used	no heat recuperation used	heat recuperation
D3.1	−1	5	5
	no system of energy management established	system of energy management into three components	system of energy management into three components

.

Based on the overall assessment of the indicators in field D—Energy Performance—all family houses achieved the highest score (5) for the indicators that rated the energy for heating and the energy for appliances. All family houses are designed to meet the energy class A for heating, as well as for electrical appliances. Further, Family Houses 2 and 3 achieved the highest score for indicators evaluating the energy for domestic hot water, solar system/heat pump, and system of energy management. Family houses also achieved a score of 5 for indicators, such as energy for mechanical ventilation and cooling and heat recuperation. In Family House 2, a heat pump for heating and hot water preparation is installed, using a type of ground-water with an integrated additional electric boiler, and is an established system of energy management for heating, cooling, lighting and shielding. In Family House 3, a solar system, as an additional source for heating and hot water preparation, is installed, using an established system of energy management for heating, ventilation, lighting and shielding, and the house uses a mechanical ventilation system, with air treatment and heat recuperation. A score of 3 was achieved for the indicator that rated the energy for domestic hot water for Family House 1. Domestic hot water obtained energy class B. A score of 0 was achieved for the indicators evaluating the energy for mechanical ventilation and cooling for Family House 2 and the energy for lighting for all family houses. Family House 2 does not use a mechanical ventilation system but rather a cooling system. A score of −1 was achieved for the indicators that rated the energy for mechanical ventilation and cooling for Family House 1, the solar system/heat pump for Family House 1 and the photovoltaic technology for all family houses, heat recuperation for Family Houses 1 and 2, and the system of energy management for Family House 1. Results show that Family Houses 3, 2 and 1 obtained rates of 4.25, 2.99 and 1.41, respectively, as shown in Table 16. It can be concluded that Family House 3 reached the best rating, with energy class A for heating and preparation of domestic hot water and for all appliances. Family House 3 uses a mechanical ventilation system, with air treatment, solar system and heat recuperation, and a system of energy management is established.

Saez de Guinoa et al. [27] assesses the life cycle environmental implications linked to the energy efficiency improvement by a nano-technological aerogel-based panel insulation solution. The developed model has been also assessed in the five European climate zones, evaluating the different performance due to the different weather conditions and the effect of increasing the thickness. This innovative aerogel-based panel takes advantage of nanotechnology to increase its lifetime and reduce its thickness, the installation time of in-building and cost, in comparison to conventional insulating materials. As a result, due to its low thermal conductivity (0.015 W/m² K), only 10 mm aerogel-based insulation panels are needed to achieve the same level of insulation, of 25 mm thickness, of standard Expanded Polystyrene Panels. This difference increases when the passive house requirements of façade thermal insulation are considered with thermal transmittance values in the range between 0.1 and 0.15 W/(m²K). From the results, a reasonable thickness of insulation material is available only with Aeropan, in comparison to Expanded Polystyrene, Extruded Polystyrene and Mineral Wool, demonstrating its suitability in the accomplishment of passive house requirements, with a significant reduction of the required space. In the paper [28], the renovation and re-use of the Atika building, a demonstrative energy-efficient building, is presented as a case study of an environmental efficient methodology for energy retrofitting. The case relies on the methodology developed by Active House. Based on the results, the integrated approach allowed for a highly efficient building, with low energy consumption. The VELUXlab building requires only 3.82 kWh/m³ per year for heating and 9.14 kWh/m³ per year for cooling. It is certified as Active House class 1 in the “primary annual energy performance” category, thanks to the strong integration of renewable energy sources (PV and solar thermal). As shown in the results, the “thermal comfort” is guaranteed to be in class 3.5 for more than 95% of the occupied hours, while the visual comfort is assured by the roof windows, which double the daylight factor (from 3% up to 6%) and assure class 1 in the “visual comfort” category. The attention given to the environmental impacts during the design allows the VELUXlab building to achieve a mean class in the overall environmental category 2, demonstrating that it is possible to optimize both embodied and operational energy impacts. Another study [29] aimed at the analysis of optimized designs for new buildings as well as different energy retrofit programs for existing buildings. They are considered in the bottom-up analysis using archetypical building energy models, located in five sites, representing a wide range of the climates in the Kingdom of Saudi Arabia (KSA). This work found that a basic energy retrofit program using low-cost energy efficiency measures implemented in the existing building stock can provide significant economic and environmental benefits. Indeed, a level 1 energy efficiency retrofit program, targeting only the existing residential building stock, reduces electricity consumption by 10,054 GWh/year, peak demand by 2290 MW and carbon emission by 7.611 million tons/year. Las-Heras-Casas et al. [30] explores the substitution of central fossil fuel boilers (heating oil, liquefied petroleum gas, and natural gas) with central biomass boilers to cover all heating and domestic hot water needs in multi-family buildings in Spain. Typical buildings from five cities, located in each different climate zone of the peninsular winter, were chosen for this study. A thorough energy, environmental, and economic analysis was conducted. From the results, it follows that a reduction by as much as 93% in primary non-renewable energy consumption can be achieved, and CO₂ emissions can decrease by as much as 94%, resulting in better and higher energy performance certificate ratings.

3.5. Water Management

The goal of water management is to preserve the site watersheds and groundwater, conserve and reuse stormwater, maintain an appropriate level of water quality on the site and in the building, reduce drinking water consumption and reduce the off-site treatment of wastewater. Criteria for the evaluated indicators in field E—Water management—can be seen in

Table 12. Criteria for the evaluated indicators in field E.

Indicator	Criteria
E1	Consumption of drinking water: there are no devices for reducing and regulating water flow or there are designed devices for reducing and regulating water flow
E2	The quality management system of water from surface runoff: water from surface runoff is not captured or water from surface runoff is captured
E3	The quality of drinking water
E4	Drinking water system and gray water system are separated: no split system is proposed, or a split system of drinking water and gray water is designed

, and the results of the evaluation of this field are presented in

Table 13. Results of the assessment of family houses in field E.

	Family House 1	Family House 2	Family House 3
	Score
E1	0	3	3
	designed equipment to reduce and control the water flow in the armature	designed equipment to reduce and control the water flow in the armature and flush toilet	designed equipment to reduce and control the water flow in the armature and flush toilet
E2	5	0	0
	collected in storage tank and is used for irrigation	sewage system and vegetation roof	sewage system and surface runoff are collected in storage tank and are used for irrigation
E3	5	5	5
	sufficient amount of fresh water with a high quality	sufficient amount of fresh water with a high quality	sufficient amount of fresh water with a high quality
E4	−1	−1	−1
	no split potable and gray water system used	no split potable and gray water system used	no split potable and gray water system used

.

In the field of water management, the highest score (5) was achieved for the indicators that rated the drinking water supply for all family houses and the water management of surface runoff for Family House 1. All houses are supplied with a sufficient amount of fresh water with a high quality. Family House 1 has established the quality management system of water from surface runoff; water from surface runoff is collected in a storage tank and is used for irrigation. A score of 3 was achieved for the indicator, rating the reduction and regulation of water flow in water systems, for Family Houses 2 and 3. Family houses have designed equipment to reduce and control the water flow in the armature and flush toilet. A score of 0 was achieved for the indicators that rated reduction and regulation of water flow in water systems for Family House 1 and for the indicator that rated the water management of surface runoff for Family Houses 2 and 3. Family House 1 has designed equipment to reduce and control the water flow only in the armature. Family Houses 2 and 3 have established a water system to capture water from surface runoff, and there is a vegetation roof. A score of −1 was achieved for the indicator that evaluated the system of grey water for all family houses. Houses do not use a split potable and grey water system. Based on the evaluation, it can be stated that Family House 1 obtained the best rate of 2.51, and Family Houses 2 and 3 achieved a value of 1.85, see Table 16. Family House 1 gains the best rating thanks to the quality management system of water from surface runoff.

The objective of the study [31] is to assess the environmental benefit of using rainwater, greywater, water-efficient appliances and their combinations in low-income houses. The study was conducted surveying twenty households located in Southern Brazil. Then, embodied energy, potential for potable water savings and sewage reduction, when using the different strategies, were estimated. The results indicated that the potential for potable water savings ranged from 21.0% (greywater reuse) to 42.9% (combining water-efficient appliances, rainwater harvesting and greywater reuse). Considering the reduction of domestic sewage, the greatest reduction occurred for the combination of greywater and water-efficient appliances, with or without rainwater harvesting (36.8%). The installation of water-efficient appliances presented a potential for sewage reduction equal to 28.9%. Embodied energy varied from 641.0 MJ (water-efficient appliances) to 25,634.6 MJ (combining water-efficient appliances, rainwater harvesting and greywater reuse).

3.6. Waste Management

The goal of waste management is to minimize the waste generated from the construction, renovation, and demolition of buildings, minimize waste generated during the building occupancy and encourage a better management of waste. Criteria for the evaluated indicators in field F—Waste management—can be seen in

Table 14. Criteria for the evaluated indicators in field F.

Indicator	Criteria
F1	Waste management plan: no waste balance is drawn up—very detailed Waste Management Plan is developed
F2	Collection, sorting and recycling of municipal waste: separate collection of waste components is not ensured—separate collection of up to 5 waste components is ensured
F3	Source of air pollution: there is a source of air pollution—there is no source of air pollution

, and the results of the evaluated houses are presented in

Table 15. Results of the assessment of family houses in field F.

	Family House 1	Family House 2	Family House 3
	Scales of Evaluating
F1	0	3	3
	prepared general waste management plan	prepared detailed waste management plan	prepared detailed waste management plan
F2	3	3	3
	ensured the separate collection of the four components of municipal waste	ensured the separate collection of the four components of municipal waste	ensured the separate collection of the four components of municipal waste
F3	−1	−1	−1
	fireplace with solid fuel	fireplace with solid fuel	fireplace with solid fuel

.

Based on the overall assessment, we can see that a score of 3 was achieved for the indicator that evaluated measures to minimize waste resulting from the building operation for all family houses and for the plan of waste disposal, originated from the construction process, for Family Houses 2 and 3. The separate collection of the four components of municipal waste (paper, plastic, glass and metal) is ensured. Family Houses 2 and 3 have prepared a detailed waste management plan in the construction process. A score of 0 was achieved for the indicators that rated the plan of waste disposal originating from the construction process for Family House 1. A general waste management plan in the construction process is prepared. A score of −1 was achieved for the indicator that evaluated measures to minimize emissions resulting from air pollution sources for all family houses. Houses have a small source of air pollution (fireplace with solid fuel) built-in. In this field, Family Houses 2 and 3 obtained better ratings of 1.64, unlike Family House 1, which obtained a rating of 0.69, as shown in Table 14. All family houses have an ensured separate collection of at least four components of municipal waste, while Family Houses 2 and 3 have a prepared detailed waste management plan in the construction process.

The area of waste management is also an important indicator of the sustainability of the construction. The study in [32] is devoted to the comparison of the environmental performance of building construction waste management (CWM) systems in Hong Kong. The LCA approach was applied to evaluate the performance of CWM systems holistically, based on primary data collected from two real building construction sites and secondary data obtained from the literature. The system boundary includes all stages of the life cycle of building construction waste (including transportation, sorting, public fill or landfill disposal, recovery and reuse, and transformation and valorization into secondary products). A substitutional LCA approach was applied to capture the environmental gains due to the utilization of recovered materials. The results showed that the CWM system resulted in significant environmental impacts by using off-site sorting and direct landfilling. However, a considerable net environmental benefit was observed through an on-site sorting system. For example, about 18–30 kg CO₂ eq. of greenhouse gases (GHGs) emissions were induced in managing 1 ton of construction waste through off-site sorting and direct landfilling, whereas significant GHGs emissions could potentially be avoided (considered as a credit of −126 to −182 kg CO₂ eq.) for an on-site sorting system due to the higher recycling potential. The environmental benefits mainly depend on the waste compositions and their sortability, although the analyses conducted in this study can serve as guidelines for designing an effective and resource-efficient building CWM system.

3.7. Results of Overall Evaluation

Based on the assessment, each family house obtained a total score and was classified according to the certification scale. An overall comparison of the evaluated family houses is shown in Figure 5, and more detailed information is presented in

Table 16. Comparison of the results of evaluated family houses by BEAS.

Field		Percentage Weight	House 1	House 2	House 3
A	Site selection and project planning	14.71%	2.00	2.18	2.32
B	Building constructions	20.59%	−0.28	0.47	0.36
C	Indoor environment	23.56%	2.40	2.30	2.80
D	Energy performance	26.47%	1.41	2.99	4.25
E	Water management	8.88%	2.51	1.85	1.85
F	Waste management	5.88%	0.69	1.64	1.64
Total assessment		100%	1.44 BEAS BRONZE	2.01 BEAS SILVER	2.46 BEAS SILVER

.

From Table 14, it can be seen that Family House 3 had the best results, with a score of 2.46, and is certified as BEAS SILVER. This family house obtained a high score in field D (4.25), C (2.80) and A (2.32). Family House 2 reached an overall score of 2.01 and is also certified as BEAS SILVER. This family house obtained a higher score in field D (2.99). The lowest overall score was reached by Family House 1, with a value of 1.44, and is therefore certified as BEAS BRONZE. However, this house obtained the highest score in field E (2.51).

4. Conclusions

The results of the evaluation of three family houses according to BEAS are discussed in relation to the main criteria, such as site selection and project planning, building constructions, indoor environment, energy performance, and water and waste management. In the assessment of site selection and project planning, the most important issues, such as the availability of the local infrastructure, the availability of civic amenities, the location of the building in relation to the flooded area, the occurrence of significant transport infrastructure and the share of green areas at the site, which significantly affect the amount of the assigned score for the object under consideration, are considered. When evaluating building construction, the important criteria are the use of recycled materials, built-in products with environmental labels, mass ²²⁶Ra activity in the construction products, such as the life cycle assessment of buildings. Assessment of the indoor environment is focused on the construction design itself, the selection of interior materials and furnishings. The evaluation of the energy performance of houses implies that considerable differences can be found in the field of the energy performance of buildings due to the use of HVAC systems, renewable energy systems as well as monitors, which control the operation and maintenance of building systems.

The assessed low-rise residential family houses are certified as BEAS BRONZE (House 1) and BEAS SILVER (Houses 2 and 3). These results may indicate a lack of awareness of the sustainable construction of buildings in Slovakia. However, a considerably larger sample of new family houses needs to be evaluated, and the percentage weight of the significance of the indicators and main fields must be made more precise. In the future, we will concentrate our attention on the aforementioned fields and indicators and thus validate the building environmental assessment system, BEAS.