Building Retrofitting
Active house

is a vision of buildings that create healthier and more comfortable lives for their occupants without negative impact on the climate – moving us towards a cleaner, healthier and safer world [48].

Air leakage is the uncontrolled flow of air through gaps and cracks in the building envelope (sometimes referred to as infiltration or draughts). This is not to be confused with ventilation, which is the controlled flow of air into and out of the building through purpose built ventilators that is required for the comfort and safety of the occupants [50].
New4Old WP4.1. (2009). Technical Guidelines for Building Designers. Greece.
Air permeability measurement

is an assessment of building envelope air leakage. This involves establishing a pressure differential across the envelope and measuring the air flow required to achieve that differential. This is normally achieved by utilising variable flow portable fans which are temporarily installed in a doorway, or other suitable external opening [49].


is the resistance of the building envelope to inward or outward air leakage. Excessive air leakage results in increased energy consumption and a draughty, cold building [49] [25].

Bioclimatic house

bioclimatic architecture refers to the design of buildings and spaces (interior – exterior – outdoor) based on local climate, aimed at providing thermal and visual comfort, making use of solar energy and other environmental sources.

Basic elements of bioclimatic design are passive solar systems which are incorporated into buildings and utilise environmental sources (for example, sun, air, wind, vegetation, water, soil, sky) for heating, cooling and lighting the buildings. Bioclimatic design takes into account the local climate and includes the following principles:

  • Heat protection of the buildings,
  • Use of solar energy for heating buildings,
  • Protection of the buildings from the summer sun,
  • Using passive cooling systems and techniques, such as natural ventilation, mostly during night time,
  • Improvement – adjustment of environmental conditions in the interiors of buildings, i.e. increasing the air movement inside spaces, heat storage, or cool storage in walls,
  • Ensuring insulation combined with solar control for day-lighting of buildings,
  • Improvement of the microclimate around buildings.
Brown roof

is a roof of a building that is partially or completely covered with non-seeded soil laid over a waterproofing membrane [25].

Building is a roofed construction having walls, for which energy is used to condition the indoor climate; a building may refer to the building as a whole or parts there of that have been designed or altered to be used separately [15] , [16].
Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings, Official Journal of European Union, 04.01.2003.
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Building element

is a technical building system or an element of the building envelope [16].

Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Building envelope are the integrated elements of a building which separate its interior from the outdoor environment [16] [53] [52].

Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Building occupant one who has certain rights to, possession of, or control over the premises occupied, such as tenant or owner [55].
ASTM E1480-92. (2004) Standard Terminology of Facility Management (Building Related).
Building unit is a section, floor or apartment within a building which is designed or altered to be used separately [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Climate active house

is the standard consisting of four main areas:
• planning and realisation,
• energy and accommodation,
• construction materials and construction,
• health and comfort.
Each area contains between 8 and 24 sub-items which are awarded with a certain amount of defined points. Similar definitions that include energy as well as other types of items have been or are currently developed in many EU Member States, such as BREEAM2 in the UK or DGNB3 in Germany [48].

Diagnostics tests are home energy assessment procedures which include a visual inspection and instrumented diagnostic testing procedure. They help detecting construction, equipment, and air distribution system installation and design flaws frequently missed by visual inspection alone (e.g., air leaks, bypasses, chase ways, duct leakage, carbon monoxide leakage, system back drafting). These tests include a blower door air infiltration test, pressure diagnostics test, and heating and cooling system inspection [9].
Wendt, R.L. (1996), Retrofit Guide for Military Family Housing: Energy Efficient Weatherization and Improvements, Oak Ridge National Laboratory, 1996, USA.
Double-skin facade is a system of building consisting of two skins placed in such a way that air flows in the intermediate cavity. The ventilation of the cavity can be natural, fan supported or mechanical. Apart from the type of the ventilation inside the cavity, the origin and destination of the air can differ depending mostly on climatic conditions, the use, the location, the occupational hours of the building and the HVAC strategy.

The glass skins can be single or double glazing units with a distance from 20 cm up to 2 metres. Often, for protection and heat extraction reasons during the cooling period, solar shading devices are placed inside the cavity [56] [57].

Eco-building is defined by the European Commission [58] as “meeting point of short-term development demonstration in order to support legislative and regulatory measures for energy efficiency and enhanced use of renewable energy solutions within the building sector, which go beyond the Directive on the Energy Performance of Buildings. Double approach: to reduce substantially, and, if possible, to avoid the demand for heating, cooling and lighting, and to supply the necessary heating, cooling and lighting in the most efficient way and based, as far as possible, on renewable energy sources and polygeneration [48].
Energy performance certificate means a certificate recognised by a Member State or by a legal person designated by it, which indicates the energy performance of a building or building unit, calculated according to a methodology adopted in accordance with Article 3 of [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Energy performance certification

provides a means of rating individual buildings – whether they be residential, commercial or public – on how efficient (or inefficient) they are in relation to the amount of energy needed to provide users with expected degrees of comfort and functionality.
The degree of efficiency depends on many factors including:

  • local climate;
  • the design of the building;
  • construction methods and materials;
  • systems installed to provide heating, ventilation, air condition or hot sanitary water; and the appliances and equipment needed to support the functions of the building and its users.

Clearly, certification is a complex procedure, requiring in-depth knowledge of building components. It also reflects increasing recognition of the need to think of buildings as "integrated systems", rather than simply the sum of their parts.
Energy certification of buildings typically involves three main steps [10]:

  • The assessment of the energy performance of a building by a competent assessor using a nominated methodology.
  • The issuance of a certificate rating the building’s energy performance which includes, in some cases, information on possible improvements likely to yield energy savings.
  • The communication of this information to stakeholders through publication of the certificate. For existing buildings, energy certification attests to the energy performance of the building, and provides information that may increase demand for more efficient buildings, thereby helping to improve the energy efficiency of the building stock.
Energy performance of a building means the calculated or measured amount of energy needed to meet the energy demand associated with a typical use of the building, which includes, inter alia, energy used for heating, cooling, ventilation, hot water and lighting [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Energy self-sufficient house

a truly energy efficient house is a self-sufficient house. Working toward self-sufficiency is the way to go toward achieving personal power and freedom.
Self sufficient & energy efficient home plans include:

  • Home solar power systems,
  • Wind generated power,
  • Thermal mass and passive solar home design,
  • Energy efficient building materials,
  • Rainwater harvesting and storage
  • Energy efficient home appliances such as, energy efficient washers and dryers, water heaters, refrigerators, energy efficient windows, and lighting.
  • An affordable design,

Energy efficient home design involves two things - finding ways to do things without using energy, and using the least amount of energy to do things that require it [59].

Energy Star Certificate

is the first part of two-step process in terms of being energy efficient rather than a designation of approved performance of the operating building. With examining the energy bills of the building, measuring and verifying of building performance would be assessed, thus the second level would also be performed.
To design a building which is aimed to have an Energy Star, the architects should set a target in terms of energy reduction and for this purpose EPA energy performance rating can be used. According to this rating the target should be higher than the level determined as minimum [35].

Green building (Green construction-Sustainable building) refers to a structure and using process that is environmentally responsible and resource-efficient throughout a building's life-cycle: from siting to design, construction, operation, maintenance, renovation, and demolition. This requires close cooperation of the design team, the architects, the engineers, and the client at all project stages [60].
The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort [61].
Although new technologies are constantly being developed to complement current practices in creating greener structures, the common objective is that the green buildings are designed to reduce the overall impact of the built environment on human health and the natural environment by:
Efficiently using energy, water, and other resources,
Protecting occupant health and improving employee productivity,
Reducing waste, pollution and environmental degradation [61].
Yan J., Stellios P. (2006). Design for Sustainability. Beijing: China Architecture and Building Press. ISBNM7-112-08390-7.
Green roof (Eco-roof)

is a planted roof top that provides benefits of water harvesting, storm water management, energy conservation, pollution reduction and aesthetic value. Green roofs vary in depth of growing media, types of plants (climate-dependent), infrastructure, and intended use [62].

Green roofs benefit the environment and local communities in many ways:

  • They filter the air and water,
  • They produce oxygen, absorb heat (during evapotranspiration) and absorb carbon dioxide,
  • They provide shade which helps to minimize the impact of the urban heat island effect and reduces the building’s air conditioning requirements, which in turn reduces the greenhouse gas emissions from burning fossil fuels for cooling,
  • They absorb rainwater which reduces storm water runoff,
  • They provide habitat for urban wildlife,
  • They provide leisure and recreational space for building occupants and the local community,
  • They insulate the building against external sound,
  • They can be used to grow local produce,
  • They protect existing roofing, which reduces the number of replacements required and roofing waste.

The basic structure of a green roof is as follows:

  • Conventional structural support,
  • Waterproof roofing membrane,
  • Root repellent system,
  • Drainage system,
  • Filtering layer,
  • Growing medium,
  • Plants [63].
Heat flow density (q) is defined as the heat loss per unit area of an external member, can be calculated as:

q = U(θi-θe)

where; θi: interior temperature and θe: exterior temperature
Heat gain of buildings:

Heat gain of buildings may occur in two different ways [64];
Solar radiation gains
Solar radiation is introduced into the building through the transparent surface of the building (glazing and walls with a transparent insulation). The amount of sunshine gains depends on the orientation of translucent surfaces and their sizes. Maximum gains of sunshine are expected in the southern areas, less in the east and west ones. For the calculation of solar gains, in addition to the orientation and thermal characteristics of transparent surfaces, it should be taken into account any shading, angle of sunlight and dirt on the windows.
Internal resources gains
Internal sources gains are the result of the release of heat in using electrical appliances and other building equipment. Even people release heat in the surrounding, that is why it is always necessary to take into account the number of fixed users of the appliances, on the calculation. Every person emits heat around 100 W (depending on his physical activity). The quantity of heat generated in the functioning of electrical devices, is often dependent on the number of users. Also regarding the artificial illumination, each lamp emits heat flux (40W, 60W, 100W). Part of the internal gains is reduced on account of evaporation (25W/person) and cold water (5W/person) [65].

Heat loss from buildings Building loses heat in two ways: with the transmission (passage of heat through the building envelope) and ventilation (ventilation losses.

Transmission heat losses

Transmission heat losses are losses due to heat transfer through the building element as a result of its thermal conductivity. Transmission heat losses are indicated through heat transfer (U) expressed in W/m2K and line heat transfer (Ø - thermal bridges) in W/mK. Transmission losses are reduced by increasing insulation and decreasing thermal bridges.

Ventilation losses

Ventilation heat losses are losses due to exchange air between the building and the surrounding area. Those can be like intentional ventilation (ventilation through windows, mechanical ventilation) or unintended and unwanted ventilation (ventilation through joints, cracks, etc...). Air-tight windows and building envelop reduce ventilation losses, but at the same time they disable the supply quantity of fresh air into the building. Therefore, the passive house as well the very good low-energy buildings requires the installation of mechanical ventilation systems with efficient heat recovery.

Heat recovery ventilation (HRV)

is an energy recovery ventilation system using equipment known as a heat recovery ventilator, heat exchanger, air exchanger, or air-to-air heat exchanger which employs a counter-flow heat exchanger (counter-current heat exchange) between the inbound and outbound air flow [66].

HRV provides fresh air and improved climate control, while also saving energy by reducing heating (and cooling) requirements. Energy recovery ventilators (ERVs) are closely related, however, ERVs also transfer the humidity level of the exhaust air to the intake air [68].

HVAC (Heating, Ventilation and Air-Conditioning) systems are designed to maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. The choice of HVAC is important for energy efficiency.
Indoor air quality is the composition and characteristics of the air in an enclosed space that affect the occupants of that space [31]. It can also be defined as the quality of the air within and around a building or a structure, related to the health and comfort of building occupants [25].
Haydaroglu, C. (2006). Türk sanayinde enerji verimliligi ve yogunlugu analizi. Anadolu University. Thesis of MS (in Turkish).
Infrared photography (or thermo graphic photography)

is often used to assess energy performance. It can determine where heat is being lost from the building envelope and can show small differences in temperature [44], [69]. In the photograph, the red and yellow areas show the heat losses from the building where the blue and green areas show the parts that have good thermal characteristic.

Insulation materials

may either be organic materials derived from animals and plants or organic synthetic materials derived from oil or inorganic mineral based materials [71].
The choice of the material for insulation purposes depends on various factors:

  • Insulation efficiency (? values),
  • Life of the material (resistance to deterioration by chemicals, moisture changes and fire),
  • Human-health friendliness,
  • Economy. While choosing the best material from EE perspective, the preference should be given to the ones that are produced with lower energy, e.g. recycled materials, organic materials, etc…
Smith, P.F. (2004), Eco-Refurbishment A Practical Guide to Creating an Energy Efficient Home, Architectural Press
Light tubes

also called sun/solar pipes, solar light, or tubular skylights, are tubes/pipes used for transport and/or distribution of natural light to another location. A light tube uses highly reflective material or plastic optical fiber to lead the light rays through a building. It can also be a prism light guide distributing light uniformly over its length [67]

Low energy house

is understood in most countries as a building with a calculated energy consumption that is significantly lower than the national requirements. This can be regarded as an informal definition, and was -and still is applied differently in different countries, sometimes even within the same country [47].

Major renovation of a building can be explained as where: a. the total cost of the renovation relating to the building envelope or the technical building systems is higher than 25 % of the value of the building, excluding the value of the land upon which the building is situated; or b. more than 25 % of the surface of the building envelope undergoes renovation [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Mixed-use building is a building with different utilization purposes reserved for different areas of the building, for example, a commercial or residential building with shops on the ground floor, office spaces on the first floor and flats on the upper floor [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Natural ventilation is the use of wind and temperature differences to create airflows in and through buildings. These airflows may be used both for ventilation air and for passive cooling strategies.
Natural ventilation is often strongly preferred by building occupants, especially if they have some control over it, as with operable windows. Studies have shown that most occupants will readily tolerate a wider range of ambient conditions if they have such control [34] [74].
Nearly zero-energy buildings is a building that has a very high energy performance. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby.
The recast EPBD (2010), in article 9, requests that the Member States shall ensure that:
a. by 31 December 2020, all new buildings are nearly zero-energy buildings; and
b. after 31 December 2018, new buildings occupied and owned by public authorities are nearly zero energy buildings.
Member States shall draw up national plans for increasing the number of nearly zero-energy buildings. Therefore, according to article 9, the Member States must have in their national plans a detailed application in practice of the definition of nearly zero-energy buildings, reflecting their national, regional or local conditions, and including a numerical indicator of primary energy use, expressed in kWh/m² per year. The national plans shall also include intermediate targets for improving the energy performance of new buildings by 2015, with a view to preparing the implementation of nearly zero-energy buildings.
In the period 2011 – 2015, the Concerted Action EPBD foresees a core theme dedicated to the topic Nearly zero-energy buildings. Within this core theme, the national approaches for applying the definition will be gathered and discussed. Plans for policies and support initiatives will be compared, and ideas for such will be exchanged between national representatives.
Night ventilation (Cooling)

is the use of the cold night air to cool down the structure of a building so that it can absorb heat gains in the daytime.
This reduces the daytime temperature rise. It is usually applied to buildings that are not occupied at night, although an occupied building would probably be ventilated anyway.
Night ventilation can be driven by natural forces – i.e. stack or wind, but may use auxiliary fan power, either to provide sufficient airflow at times when the natural forces are weak, or to allow smaller ducts (causing greater resistance) to be used [75] [76], [79].

Occupancy profile/patterns The results of the retrofit program will improve if installation personnel and housing occupants understand why energy efficiency is important. It is also of importance that the occupancy profile is well-evaluated by education can help improve occupant comfort by promoting the proper use of energy-efficient appliances and equipment [9].
Wendt, R.L. (1996), Retrofit Guide for Military Family Housing: Energy Efficient Weatherization and Improvements, Oak Ridge National Laboratory, 1996, USA.
Passive house An example of a high performance building term with a rather exact quantitative definition is the passive house. Several countries (Austria, Germany, Czech Republic and Denmark) use the same definition, which was developed by a private organisation for the German building market:
• Maximum calculated net energy use for heating: 15 kWh/m2year,
• Maximum total calculated primary energy consumption: 120 kWh/m2a,
• Required air-tightness value: n50 = 0.6 1/h [47].

Passive house refers to standard for energy efficiency in a building, reducing its ecological footprint. Passive design is not an attachment or supplement to architectural design, but a design process that is integrated with architectural design.
Although it is mostly applied to new buildings, it has also been used for refurbishments [60], [80].
Yan J., Stellios P. (2006). Design for Sustainability. Beijing: China Architecture and Building Press. ISBNM7-112-08390-7.
Zeller, Jr., Tom. (2010).Beyond Fossil Fuels: Can We Build in a Brighter Shade of Green, New York Times. p.BU1.
Passive Solar Heat Gain: In passive solar building design, windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design or climatic design because, unlike active solar heating systems, it doesn't involve the use of mechanical and electrical devices [81] [82].
Doerr, Thomas (2012) Passive Solar Simplified (1st ed.). USA, Alitheia Press
Passive solar heating is one of several design approaches collectively called passive solar design. When combined properly, these strategies can contribute to the heating, cooling, and day-lighting of nearly any building.
The types of buildings that benefit from the application of passive solar heating; range from barracks to large maintenance facilities.
Typically, passive solar heating involves:
• The collection of solar energy through properly-oriented, south-facing windows
• The storage of this energy in "thermal mass," comprised of building materials with high heat capacity such as concrete slabs, brick walls, or tile floors
• The natural distribution of the stored solar energy back to the living space, when required, through the mechanisms of natural convection and radiation
• Window specifications to allow higher solar heat gain coefficient in south glazing.
Passive solar heating systems do not have a high initial cost or long-term payback period, both of which are common with many active solar heating systems. Increased user comfort is another benefit to passive solar heating. If properly designed, passive solar buildings are bright and sunny and in tune with the nuances of climate and nature. As a result, there are fewer fluctuations in temperature, resulting in a higher degree of temperature stability and thermal comfort. By providing a delightful place to live and work, passive solar buildings can contribute to increased satisfaction and user productivity. In addition, passive solar design does not generate greenhouse gases and slows fossil fuel depletion [83].
Payback period period is the length of time required to recover the cost of an investment. The payback period of a given investment or project is an important determinant of whether to undertake the position or project, as longer payback periods are typically not desirable for investment positions. Calculated as [84].

Payback Period = Cost of Project / Annual Cash Inflows
Plus-energy house produces more energy from renewable energy sources, over the course of a year, than it imports from external sources.
This is achieved using a combination of microgeneration technology and low-energy building techniques, such as: passive solar building design, insulation and careful site selection and placement. A reduction of modern conveniences can also contribute to energy savings, however many energy-plus houses are almost indistinguishable from a traditional home, preferring instead to use highly energy-efficient appliances, fixtures, etc., throughout the house [82].
Positive energy building is a building where, as a result of its very high level of energy efficiency, the overall annual primary energy consumption is less than the energy (produced from renewable energy sources) supplied to the building [25].
Precooling/Preheating Pre-heating coil used to warm up the air entering the supply ducted system to a predefined value (e.g.; not controlled according to indoor temperature) Pre-cooling coil used to cool down the air entering the supply ducted system to a predefined value [89].
European Standard : CEN/TC 156 (2010). Ventilation for Buildings.
Recycling is a process by which a discarded material is collected, sorted, processed and converted into raw materials which are then used in the production of new products [25].
Shading devices Exterior shading devices such as overhangs and vertical fins have a number of advantages that contribute to a more sustainable building.
First, exterior shading devices result in energy savings by reducing direct solar gain through windows.
By using exterior shading devices with less expensive glazing, it is sometimes possible to obtain performance equivalent to unshaded higher performance glazing.
A second benefit is that peak electricity demand is also reduced by exterior shading devices resulting in lower peak demand charges from utilities and reduced mechanical equipment costs. Finally, exterior shading devices have the ability to reduce glare in an interior space without the need to lower shades or close blinds.
This means that daylight and view are not diminished by dark tinted glazing or blocked by interior shades. With exterior shading devices, glare control does not depend on user operation [90].
External shading devices are a passive design strategy to control solar heat gain in buildings, and influences energy performance. It can reduce solar heat gain more effectively than interior devices, and its efficiency depends on the provided shading [91], [92].
In hot climates, the use of shading devices is desirable, intercepting the unwanted solar rays of overheating period. These elements influence heat gain, especially in relation to location and orientation [93].
Carmody, J., Haglund. K. (2006) External Shading Devices in Commercial Buildings. Minnesota, University of Minnesota Copyright.
Olgyay, A. and Olgyay, V. (1957), Solar control and shading devices, Princeton University Press (London: Oxford University Press), Pp. 201; 180 Figs.
ASHRAE 20 ANSI/ASHRAE/IESNA Standard 90.1-200, Energy Standard for Buildings Except for Low-Rise Residential Buildings. Atlanta: American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc.
Gutierrez, G. C. R. ; Labaki, L. C. (2007), An experimental study of shading devices: orientation, typology and material. In: Buildings X - Thermal Performance of the Exterior Envelopes of Whole Buildings X, Clearwater Beach, Florida. Proceedings of Thermal Performance of the Exterior Envelopes of Whole Buildings X. Oak Ridge : ASHRAE, ORNL,. v. 1. p. 1-10.
Smart home system (SHS) is an approach to building automation, which may include the centralized control of lighting, HVAC, appliance and other systems, by means of computer and information technology to provide improved energy efficiency, security, comfort and convenience [94].
Gerhart, J. (1999), Home Automation and Wiring, USA, McGraw-Hill Company.
Solar chimney can be used to improve natural ventilation in buildings by encouraging the convection of air upwards. A solar chimney can assist natural ventilation, particularly in regions with high solar irradiation and low wind speeds [96] [97]. Heat recovery can be used in the chimney to collect energy for heating domestic hot water, or stored in a Thermal-bank for use in a cold season [95].
Solar cooling technologies are mainly classified into two main groups depending on the energy supply: a thermal/work driven system and electricity (Photovoltaic) driven system. The solar-powered cooling system generally comprises three main parts: the solar energy conversion equipment, the refrigeration system, and the cooled object (e.g. a cooling box) [98].
Solar radiation is radiant energy emitted by the sun, particularly electromagnetic energy.
Solar Wall utilizes the free solar energy from the sun to heat air for the building ventilation system. This is non-polluting and uses renewable energy. The wall is incorporated in the building structure utilizing the air space between the Solar Wall and the structures interior building. That air space is heated by the Sun's rays then drawn into the building to heat the occupied spaces [99], [100].
3(Three)-litre-house calculated primary energy consumption for heating and ventilation, using the national calculation standard, corresponding to maximum 3 litres of oil per m2 (~34 kWh/m2yr primary energy consumption) [47].
Tacit knowledge knowledge derived from studies and experience. It is subconsciously understood and/ or applied but it is personal, context-specific and difficult to articulate. It is often called informal knowledge or even wisdom. Tacit knowledge has been described as “know-how” -- as opposed to “know-what” (facts), “know-why” (science), or “know-who” (networking).
Technical building system is the technical equipment for the heating, cooling, ventilation, hot water, lighting or for a combination thereof, of a building or building unit [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
The blower door test is conducted by mounting a high powered fan to the exterior door frame which pulls the air out of the building. The difference in pressure inside versus outside the building is measured and overall air-tightness of the building is determined. In a typical blower door test the fan blows air out of the house to create a slight pressure difference between the inside and outside of the house [104].
This pressure difference forces outside air into the house through all holes, cracks, and penetrations in the building envelope.
Thermal comfort is defined in British Standard BS EN ISO 7730 (2006) [105] as: ‘that condition of mind which expresses satisfaction with the thermal environment.
Thus, the term ‘thermal comfort’ describes a person’s psychological state of mind and is usually referred to in terms of whether someone is feeling too hot or too cold. Thermal comfort is very difficult to define because you need to take into account a range of environmental and personal factors when deciding what will make people feel comfortable. These factors make up what is known as the ‘human thermal environment’. The best that you can realistically hope to achieve is a thermal environment that satisfies the majority of people in the workplace, or put more simply, ‘reasonable comfort’ [106].
Thermal conductivity (k-value) is defined as the amount of heat energy transferred per unit thickness for a given temperature difference, expressed in W/mK. The lower this value the more energy efficient is the material [71]. However, the thermal conductivity of a material is affected by density, moisture and temperature of the material, e.g. when the material is moisture saturated the thermal conductivity is increased.
Smith, P.F. (2004), Eco-Refurbishment A Practical Guide to Creating an Energy Efficient Home, Architectural Press.
Thermal envelope The term ‘thermal envelope’ refers to the shell of the building as a barrier to unwanted heat or mass transfer between the interior of the building and the outside conditions. The effectiveness of the thermal envelope depends on
(i) the insulation levels in the walls, ceiling and ground or basement floor, including factors such as moisture condensation and thermal bridges that affect insulation performance;
(ii) the thermal properties of windows and doors; and
(iii) the rate of exchange of inside and outside air, which in turn depends on the air-tightness of the envelope and driving forces such as wind, inside-outside temperature differences and air pressure differences due to mechanical ventilation systems or warm/cool air distribution [101].
Thermal insulation is a physical barrier that prevents the unnecessary heat gain/loss, and it is essential to achieve thermal comfort of the occupants. In narrow sense “insulation” refers the materials having a k-value lower than 0.05 to 0.07 W/mK. These materials are being used to provide a considerable slowed down flow of the heat. As conduction is the major mode of heat transfer and air is a low-cost insulator, these products should be manufactured from low-density (porous) or low-conductivity materials. It can be possible to mention the two main types of insulation:
Bulk Insulation is relying on the resistance capacity of the materials having pockets trapping air within the structure.
Reflective Insulation is relying on the materials’ reflection capacity of radiant heat flow because of its high reflective and low emissivity characteristics, e.g. shiny aluminium foil coating [48], [65].
Thermal resistance and thermal transmittance in-situ measurement is a heat flowmeter method for the measurement of the thermal transmission properties (thermal resistance and thermal conductance from surface to surface, total thermal resistance and transmittance from environment to environment) of plane building components, primarily consisting of opaque layers perpendicular to the heat flow and having no significant lateral heat flow [102].
ISO 9869 (1994) Thermal insulation- Building elements – In situ measurement of thermal resistance and thermal transmittance
Thermo controller valves are the instruments that enable to control the level of conditions e.g. temperature, liquid, flow, etc. by completely or partially opening/closing in response to the signals acquired from the controllers, by comparing a set-point to a process variable whose value is provided by sensors [103].
Bela G. Liptak (Editor). (2003) Instrument Engineers' Handbook (4th Edition ed.). Florida. CRC Press.
Thermo-hygrometers are the tools to measure the temperature and relative humidity. By inserting different probes, it is possible to take measurements from different width levels of the building member. The relative humidity, together with the ambient temperature influences the thermal comfort of the building.
Triple zero house (Germany); The annual balance of calculated primary energy consumption is 0. Use of recycled material only (closed material loop). The annual balance of emissions (from energy consumption) is 0 [47].
Trombe wall is named after a French engineer Félix Trombe, who popularized this heating system in the early 1960s. The idea actually goes back a lot further. A thermal-mass wall was patented in 1881 by Edward Morse. In the U.S., interest in Trombe walls emerged in the 1970s, aided by researchers at Los Alamos National Laboratory in New Mexico. Trombe walls are particularly well-suited to sunny climates that have high diurnal (day-night) temperature swings, such as the mountain-west [108].
They don't work as well in cloudy climates or where there isn't a large diurnal temperature swing [107].
U-value is the measure of the rate of heat loss through a material. It is measured as the amount of heat lost through a one square meter of the material for every degree difference in temperature either side of the material. U-value is indicated in W/m2K [44].
Very low energy house is any type of house that from design, technologies and building products uses less energy, from any source, than a traditional or average contemporary house. In the practice of sustainable design, sustainable architecture, low-energy building, energy-efficient landscaping low-energy houses often use active solar and passive solar building design techniques and components to reduce their energy expenditure.
The definition of very low energy buildings varies significantly across Europe even though the EPBD (Energy Performance of Buildings Directive) give guidelines for the calculations. The variation exists not only in terms of the absolute level of energy consumption in a low energy building, but also the deviation from the minimum requirements as stated in the national Building Regulations (see Technical issues). Further the national calculation methods vary from country to country, which makes it rather complicated to compare the absolute values of the energy requirements. The EU project ASIEPI (Assessment and Improvement of the EPBD Impact for new buildings and building renovation), 2007-2010, will make a benchmarking method in order to compare the current energy performance requirement levels in the MS and to make it possible to follow the evolution of the requirements over time. Therefore it was not the intention of this study to compare the absolute level of requirements for the different definitions used.
Water and moisture insulation water can enter into the structure by percolation in liquid phase and by means of air currents, diffusion through materials and heat transfer, in vapour phase [110].
In addition to structural integrity, moisture is also harmful on human health in terms of the possibility to provide an available environment to micro-organisms.
The dampness in structural elements based on three types:
• Rising or capillary dampness,
• Falling or penetrating dampness,
• Condensation dampness. Water and moisture insulation of an element or a whole-building can be provided by using either flexible materials e.g. bitumen mastic, metal sheets, rubber, etc. and rigid materials e.g. rich concrete, stone slabs, etc...
White certificates are issued by independent certifying bodies confirming the energy savings claims of market actors as a consequence of energy efficiency improvement measures [1].
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Yearly heating/cooling demand is the total heating or cooling energy that has to be supplied for the building from heating or cooling system per year.
Zero-energy house-Zero-emission house-Zero-carbon house The definitions for zero-energy/emission/carbon buildings can be interpreted in different ways and should be analysed with care. These buildings can either be defined as to consume no energy or emit no carbon at all, which is a very expensive strategy, as large storage systems for heating and cooling or even for electricity are needed, or they can be defined as yearly balanced buildings. In this case, the buildings still consume energy, but produce in one period of the year at least as much energy as they need during the whole year. The realisation is mostly made by including renewable technologies (mainly solar and/or biomass) in the energy concept. Thus, the buildings have the same definitions as energy/emission/carbon neutral buildings [47].
A Zero Energy Home (ZEH) combines high levels of energy efficiency with renewable energy systems to annually return as much energy to the utility as it takes from the utility –resulting in a net-zero energy consumption for the home [111].