EEWH is the green building certification system in Taiwan . EEWH comprises nine indicators that fall into four categories - ecology , energy saving, waste reduction and health - hence the name EEWH. The system was launched in 1999.
77-501: Since 2003, the indicators have been foliage; water soil content (infiltration and retention); energy savings (for the building envelope , lighting and HVAC ); CO 2 emissions reduction; construction waste reduction; water conservation ; garbage and sewage improvements; biodiversity ; and indoor environmental quality. EEWH has five levels: certified, bronze, silver, gold, and diamond. As of May 2008, one building ( Beitou Public Library ) had been rated diamond level, and one gold. EEWH
154-492: A radiant barrier ) but it can also involve a range of designs and techniques to address the main modes of heat transfer - conduction, radiation, and convection materials. Most of the materials in the above list only retain a large amount of air or other gases between the molecules of the material. The gas conducts heat much less than the solids. These materials can form gas cavities, which can be used to insulate heat with low heat transfer efficiency. This situation also occurs in
231-418: A ceiling. The difference can be illustrated by the fact that an insulated attic floor is the primary thermal control layer between the inside of the house and the exterior while the entire roof (from the surface of the roofing material to the interior paint finish on the ceiling) is part of the building envelope. Building envelope thermography involves using an infrared camera to view temperature anomalies on
308-642: A combination of both types to make up a total building insulation system. The type of insulation used is matched to create maximum resistance to each of the three forms of building heat transfer - conduction, convection, and radiation. According to three ways of heat exchange, most thermal insulation we use in our buildings can be divided into two categories: Conductive and convective insulators and radiant heat barriers. And there are more detailed classifications to distinguish between different materials. Many thermal insulation materials work by creating tiny air cavities between molecules, these air cavities can largely reduce
385-521: A continuous path across a temperature difference, in which the heat flow is not interrupted by thermal insulation. Common building materials that are poor insulators include glass and metal . A building design may have limited capacity for insulation in some areas of the structure. A common construction design is based on stud walls, in which thermal bridges are common in wood or steel studs and joists , which are typically fastened with metal. Notable areas that most commonly lack sufficient insulation are
462-651: A higher insulation value (the legally obtained level), then this value counts as a lower limit. Insulation requirements for new houses and small buildings in New Zealand are set out in the Building Code and standard NZS 4128:2009. Zones 1 and 2 include most of the North Island , including Waiheke Island and Great Barrier Island . Zone 3 includes the Taupo District , Ruapehu District , and
539-636: A relatively high R-value of around R-10 per inch which is considerably higher compared with conventional plastic foam insulation materials, due to their designed high porosity. But the difficulties in processing and low productivity limit the development of Aerogels, the cost price of this material still remains at a high level. Only two companies in the United States offer the commercial Aerogel product for wall insulation purposes. The DOE estimates thermal losses nearing 30% through windows, and thermal gains from sunlight leading to unwanted heating. Due to
616-458: A researcher at the University of Colorado Boulder, recently demonstrated the capabilities of aerogels by designing a silanized cellulose aerogel (SiCellA) which offers near 99% visible transmission in addition to thermal conductivities which effectively reject or retain heat depending on the interior environment, akin to heating/cooling alterations. This is due to the designed 97.5% porosity of
693-419: A routine part of a whole-house energy audit . However, you can sometimes perform a self-assessment in certain areas of the home, such as attics. Here, a visual inspection, along with use of a ruler, can give you a sense of whether you may benefit from additional insulation. Residential energy audits are often initiated due homeowners being alerted by a gradual increase in their utility bills which often reflects
770-455: A significant role in buildings, great demands of thermal comfort result in a large amount of energy consumed for full-heating for all rooms. Around 40% of energy consumption can be attributed to the building, mainly consumed by heating or cooling. Sufficient thermal insulation is the fundamental task that ensures a healthy indoor environment and against structure damages. It is also a key factor in dealing with high energy consumption, it can reduce
847-412: A thinner thickness of thermal insulation to the building shell compared with traditional materials. The VIPs are usually composed of core panels and metallic enclosures. The common materials that used to produce Core panels are fumed and precipitated silica, open-cell polyurethane (PU), and different types of fiberglass. And the core panel is covered by the metallic enclosure to create a vacuum environment,
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#1732791091507924-444: A vapor barrier. Moisture control (e.g. damp proofing ) is essential in all climates, but cold climates and hot-humid climates are especially demanding. Air sealing can improve the energy efficiency of a building by minimizing the amount of energy needed to heat or cool the building. This is especially pertinent in cold-climate buildings where space heating consumes the largest amount of energy. A blower door test can be used to test
1001-427: A wall or ceiling that may result in 10% to 20% of the heat loss alone. The physical components of the envelope include the foundation , roof , walls , doors , windows , ceiling , and their related barriers and insulation . The dimensions, performance and compatibility of materials, fabrication process and details, connections and interactions are the main factors that determine the effectiveness and durability of
1078-462: Is an important climate change mitigation tactic , especially when buildings are heated by oil, natural gas, or coal-based electricity. Local and national governments and utilities often have a mix of incentives and regulations to encourage insulation efforts on new and renovated buildings as part of efficiency programs in order to reduce grid energy use and its related environmental impacts and infrastructure costs. Thermal insulation usually refers to
1155-513: Is lost or gained by transmission through the ceilings, walls, floors, windows, and doors. This heat reduction and acquisition are usually unwelcome. It not only increases the load on the HVAC system resulting in more energy wastes but also reduces the thermal comfort of people in the building. Thermal insulation in buildings is an important factor in achieving thermal comfort for its occupants. Insulation reduces unwanted heat loss or gain and can decrease
1232-556: Is material used in a building (specifically the building envelope ) to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation , fire insulation , and impact insulation (e.g. for vibrations caused by industrial applications). Often an insulation material will be chosen for its ability to perform several of these functions at once. Since prehistoric times, humans have created thermal insulation with materials such as animal fur and plants. With
1309-629: Is not equivalent to LEED ( Leadership in Energy and Environmental Design Green Building Rating System) in the United States , CASBEE (Comprehensive Assessment System for Building Environmental Efficiency) in Japan , and HQE in France. This Taiwan -related article is a stub . You can help Misplaced Pages by expanding it . Building envelope A building envelope or building enclosure
1386-408: Is the installation of an insulation board (e.g. foam board EPS XPS, wood fibre board, etc.) over the exterior outside wall. Another method is using insulated lumber framing for a thermal break inside the wall. Insulating buildings during construction is much easier than retrofitting, as generally the insulation is hidden, and parts of the building need to be deconstructed to reach them. Depending on
1463-471: Is the minimum insulation requirements based on climate, which is determined by the Building Code of Australia (BCA). The building in Australia applies insulation in roofs, ceilings, external walls, and various components of the building (such as Veranda roofs in the hot climate, Bulkhead, Floors). Bulkheads (wall section between ceilings which are in different heights) should have the same insulated level as
1540-536: Is the physical separator between the conditioned and unconditioned environment of a building , including the resistance to air, water, heat, light, and noise transfer. The building envelope or enclosure is all of the elements of the outer shell that maintain a dry, heated, or cooled indoor environment and facilitate its climate control . Building envelope design is a specialized area of architectural and engineering practice that draws from all areas of building science and indoor climate control. The many functions of
1617-591: Is weak and radiation dominates heat transfer across an air space. Radiant barriers must face an adequate air-gap to be effective. If refrigerative air-conditioning is employed in a hot, humid climate, then it is particularly important to seal the building envelope. Dehumidification of humid air infiltration can waste significant energy. On the other hand, some building designs are based on effective cross-ventilation instead of refrigerative air-conditioning to provide convective cooling from prevailing breezes. In hot dry climate regions like Egypt and Africa, thermal comfort in
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#17327910915071694-795: The Rangitikei District north of 39°50′ latitude south (i.e. north of and including Mangaweka ) in the North Island, the South Island , Stewart Island , and the Chatham Islands . Insulation requirements are specified in the Building regulations and in England and Wales the technical content is published as Approved Documents Document L defines thermal requirements, and while setting minimum standards can allow for
1771-401: The 1995 versions reduced energy depletion per square meter for heating by 20%, and the 2000 version reduced by 40%. The code also has a mandatory requirement on thermal insulation of buildings accompany with some voluntary provisions, mainly focused on heat loss from the building shell. The thermal insulation requirements of Australia follow the climate of the building location, the table below
1848-418: The 19th century, people were no longer satisfied with using natural materials for thermal insulation, they processed the organic materials and produced the first insulated panels. At the same time, more and more artificial materials start to emerge, and a large range of artificial thermal insulation materials were developed, e.g. rock wool, fiberglass, foam glass, and hollow bricks. Thermal insulation can play
1925-470: The Netherlands makes a clear distinction between home renovation or newly built houses. New builds count as completely new homes, but also new additions and extensions are considered to be new builds. Furthermore, renovations whereby at least 25% of the surface of the integral building is changed or enlarged is also considered to be a new build. Therefore, during thorough renovations, there's a chance that
2002-591: The SiCellA: pores are smaller than the wavelength of visible light, leading to transmission; the pores also minimize contact between the cellulose fibers, leading to lower thermal conductivities. The use of cellulose fibers lends itself to sustainability, as this is a naturally derived fiber sourced from wood pulps. This opens the door not only to aerogels, but also more general wood-based materials implementation in an effort to assist sustainable design alternatives with compounding energy saving effects. In hot conditions,
2079-491: The U values for elements such as roofs and walls to be traded off against other factors such as the type of heating system in a whole building energy use assessment. Scotland and Northern Ireland have similar systems but the detail technical standards are not identical. The standards have been revised several times in recent years, requiring more efficient use of energy as the UK moves towards a low-carbon economy . In cold conditions,
2156-556: The agricultural development, earth, stone, and cave shelters arose. In the 19th century, people started to produce insulated panels and other artificial materials. Now, insulation is divided into two main categories: bulk insulation and reflective insulation. Buildings typically use a combination. Insulation is an important economic and environmental investment for buildings. By installing insulation, buildings use less energy for heating and cooling and occupants experience less thermal variability. Retrofitting buildings with further insulation
2233-404: The amount of non-insulative (particularly non-solar facing) glazing. Indoor thermal radiation can also be a disadvantage with spectrally selective (low-e, low-emissivity ) glazing. Some insulated glazing systems can double to triple R values. The vacuum panels and aerogel wall surface insulation are two technologies that can enhance the energy performance and thermal insulating effectiveness of
2310-410: The building enclosure system. Common measures of the effectiveness of a building envelope include physical protection from weather and climate (comfort), indoor air quality (hygiene and public health), durability and energy efficiency . In order to achieve these objectives, all building enclosure systems must include a solid structure, a drainage plane, an air barrier, a thermal barrier, and may include
2387-401: The building envelope can be separated into three categories: The control function is at the core of good performance, and in practice focuses, in order of importance, on rain control, air control, heat control, and vapor control. Control of rain is most fundamental, and there are numerous strategies to this end, namely, perfect barriers, drained screens, and mass / storage systems. One of
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2464-643: The building performance was introduced in 2002. And the 2009 version of the Energy Saving Ordinance increased the minimum R-values of the thermal insulation of the building shell and introduced requirements for air-tightness tests. The Energy Saving Ordinance (EnEV) 2013 clarified the requirement of thermal insulation of the ceiling. And it mentioned that if the ceiling was not fulfilled, thermal insulation will be needed in accessible ceilings over upper floor's heated rooms. [U-Value must be under 0.24 W/(m ⋅K)] The building decree (Bouwbesluit) of
2541-807: The buildings attic as being poorly insulated. An initial estimate of insulation needs in the United States can be determined by the US Department of Energy's ZIP code insulation calculator . In Russia , the availability of abundant and cheap gas has led to poorly insulated, overheated, and inefficient consumption of energy. The Russian Center for Energy Efficiency found that Russian buildings are either over- or under-heated, and often consume up to 50 percent more heat and hot water than needed. 53 percent of all carbon dioxide (CO 2 ) emissions in Russia are produced through heating and generating electricity for buildings. However, greenhouse gas emissions from
2618-493: The ceilings since they suffer the same temperature levels. And the external walls of Australia's building should be insulated to decrease all kinds of heat transfer. Besides the walls and ceilings, the Australia energy code also requires insulation for floors (not all floors). Raised timber floors must have around 400mm soil clearance below the lowest timbers to provide sufficient space for insulation, and concrete slab such as suspended slabs and slab-on-ground should be insulated in
2695-582: The climate zone, it means that the amount of insulation needed for a building is determined by which climate zone the building locates. The thermal insulation requirements are shown as R-value and continuous insulation R-value as the second index. The requirements for different types of walls (wood framed walls, steel framed walls, and mass walls) are shown in the table. To determine whether you should add insulation, you first need to find out how much insulation you already have in your home and where. A qualified home energy auditor will include an insulation check as
2772-401: The cold climate areas, a large amount of thermal insulation is needed to deal with the heat losses caused by cold weather (infiltration, ventilation, and radiation). There are two technologies that are worth discussing: VIPs are noted for their ultra-high thermal resistance, their ability of thermal resistance is four to eight times more than conventional foam insulation materials which lead to
2849-431: The context of sustainable architecture for green certifications such as LEED . The insulation strategy of a building needs to be based on a careful consideration of the mode of energy transfer and the direction and intensity in which it moves. This may alter throughout the day and from season to season. It is important to choose an appropriate design, the correct combination of materials, and building techniques to suit
2926-410: The corners of buildings, and areas where insulation has been removed or displaced to make room for system infrastructure, such as electrical boxes (outlets and light switches), plumbing, fire alarm equipment, etc. Thermal bridges can also be created by uncoordinated construction, for example by closing off parts of external walls before they are fully insulated. The existence of inaccessible voids within
3003-406: The correct installation of insulative materials. The less natural airflow into a building, the more mechanical ventilation will be required to support human comfort. High humidity can be a significant issue associated with lack of airflow, causing condensation , rotting construction materials, and encouraging microbial growth such as mould and bacteria . Moisture can also drastically reduce
3080-445: The country there are different regulations as to which type of insulation is the best alternative for buildings, considering energy efficiency and environmental factors. Geographical location also affects the type of insulation needed as colder climates will need a bigger investment than warmer ones on installation costs. There are essentially two types of building insulation - bulk insulation and reflective insulation. Most buildings use
3157-403: The drawback of this technology is obvious that the high reflectivity will cause visual discomfort. On the other hand, the high reflectivity and thermal emittance of the roof will increase the heating load of the building. Optimal placement of building elements (e.g. windows, doors, heaters) can play a significant role in insulation by considering the impact of solar radiation on the building and
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3234-422: The effectiveness of insulation by creating a thermal bridge (see below). Air exchange systems can be actively or passively incorporated to address these problems. Thermal bridges are points in the building envelope that allow heat conduction to occur. Since heat flows through the path of least resistance, thermal bridges can contribute to poor energy performance. A thermal bridge is created when materials create
3311-426: The enclosure (the assembly of materials that perform this function is termed the air barrier system) or through components of the building envelope (interstitial) itself, as well as into and out of the interior space, (which can affect building insulation performance greatly). Hence, air control includes the control of windwashing (cold air passing through insulation) and convective loops which are air movements within
3388-591: The energy demands of heating and cooling systems. It does not necessarily deal with issues of adequate ventilation and may or may not affect the level of sound insulation. In a narrow sense, insulation can just refer to the insulation materials employed to slow heat loss, such as: cellulose , glass wool , rock wool , polystyrene , polyurethane foam , vermiculite , perlite , wood fiber , plant fiber ( cannabis , flax , cotton , cork , etc.), recycled cotton denim , straw , animal fiber ( sheep's wool ), cement , and earth or soil, reflective insulation (also known as
3465-648: The former Soviet Bloc are still below their 1990 levels. Energy codes in the Soviet Union start to establish in 1955, norms and rules first mentioned the performance of the building envelope and heat losses, and they formed norms to regulate the energy characteristics of the building envelope. And the most recent version of Russia energy code (SP 50.13330.2012) was published in 2003. The energy codes of Russia were established by experts of government institutes or nongovernmental organization like ABOK. The energy code of Russia have been revised several times since 1955,
3542-517: The former being 0.176 times the latter numerically, or the reciprocal quantity the thermal conductivity or U-value W⋅K ⋅m . For example, in the US the insulation standard for attics, is recommended to be at least R-38 US units, (equivalent to R-6.7 or a U value of 0.15 in SI units). The equivalent standard in the UK are technically comparable, the approved document L would normally require an average U value over
3619-521: The fur of animals and birds feathers, animal hair can employ the low thermal conductivity of small pockets of gas, so as to achieve the purpose of reducing heat loss. The effectiveness of reflective insulation (radiant barrier) is commonly evaluated by the reflectivity (emittance) of the surface with airspace facing to the heat source. The effectiveness of bulk insulation is commonly evaluated by its R-value , of which there are two – metric (SI) (with unit K⋅W ⋅m ) and US customary (with unit °F⋅ft ⋅h/BTU),
3696-485: The greatest source of heat energy is solar radiation. This can enter buildings directly through windows or it can heat the building shell to a higher temperature than the ambient, increasing the heat transfer through the building envelope. The Solar Heat Gain Co-efficient (SHGC) (a measure of solar heat transmittance) of standard single glazing can be around 78–85%. Solar gain can be reduced by adequate shading from
3773-416: The heat exchange through the materials. But there are two exceptions which don't use air cavities as their functional element to prevent heat transfer. One is reflective thermal insulation, which creates a great airspace by forming a radiation barrier by attaching metal foil on one side or both sides, this thermal insulation mainly reduces the radiation heat transfer. Although the polished metal foil attached on
3850-460: The heat exchange. Later, human beings' long life spans and the development of agriculture determined that they needed a fixed place of residence, earth-sheltered houses , stone houses, and cave dwellings began to emerge. The high density of these materials can cause a time lag effect in thermal transfer, which can make the inside temperature change slowly. This effect keep inside of the buildings warm in winter and cool in summer, also because of
3927-427: The heat flow through the building envelope. Good thermal insulation can also bring the following benefits to the building: How much insulation a house should have depends on building design, climate, energy costs, budget, and personal preference. Regional climates make for different requirements. Building codes often set minimum standards for fire safety and energy efficiency , which can be voluntarily exceeded within
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#17327910915074004-436: The high R associated with aerogels, their use for glazing applications has become an area of interest explored by many research institutions. Their implementation, however, must not hinder the primary function of windows: transparency. Typically, aerogels have low transmission and appear hazy, even amongst those considered transparent, which is why they have generally been reserved to wall insulation applications. Eldho Abraham,
4081-445: The interior and exterior surfaces of the structure. Analysis of infrared images can be useful in identifying moisture issues from water intrusion, or interstitial condensation . Other types of anomalies that can be detected are thermal bridging, continuity of insulation and air leakage, however this requires a temperature differential between the inside and outside ambient temperatures. Building insulation Building insulation
4158-593: The long term and this system is very limited, but ordinary residential construction often treats walls as sealed-surface systems relying on the siding and an underlayment layer sometimes called housewrap . Moisture can enter basements through the walls or floor. Basement waterproofing and drainage keep the walls dry and a moisture barrier is needed under the floor. Control of airflow is important to ensure indoor air quality, control energy consumption, avoid condensation (and thus help ensure durability), and to provide comfort. Control of air movement includes flow through
4235-638: The main aim is to reduce heat flow out of the building. The components of the building envelope—windows, doors, roofs, floors/foundations, walls, and air infiltration barriers—are all important sources of heat loss; in an otherwise well insulated home, windows will then become an important source of heat transfer. The resistance to conducted heat loss for standard single glazing corresponds to an R-value of about 0.17 m ⋅K⋅W or more than twice that for typical double glazing (compared to 2–4 m ⋅K⋅W for glass wool batts ). Losses can be reduced by good weatherisation , bulk insulation, and minimising
4312-427: The main purposes of a roof is to resist water. Two broad categories of roofs are flat and pitched. Flat roofs actually slope up to 10° or 15° but are built to resist intrusion from standing water. Pitched roofs are designed to shed water but not resist standing water intrusion which can occur during wind-driven rain or ice damming . Typically residential, pitched roofs are covered with an underlayment material beneath
4389-401: The material, since the edge of the vacuum panel can form a thermal bridge which leads to a reduction of the effectiveness of the vacuum insulation. The effectiveness of the vacuum insulation is also related to the area of the vacuum panels. Bulk insulators block conductive heat transfer and convective flow either into or out of a building. Air is a very poor conductor of heat and therefore makes
4466-402: The materials can only prevent the radiation heat transfer, its effect to stop heat transfer can be dramatic. Another thermal insulation that doesn't apply air cavities is vacuum insulation, the vacuum-insulated panels can stop all kinds of convection and conduction and it can also largely mitigate the radiation heat transfer. But the effectiveness of vacuum insulation is also limited by the edge of
4543-524: The materials like earth or stone is easy to get, this design is really popular in many places like Russia, Iceland, Greenland. Organic materials were the first available to build a shelter for people to protect themselves from bad weather conditions and to help keep them warm. But organic materials like animal and plant fiber cannot exist for a long time, so these natural materials cannot satisfy people's long-term need for thermal insulation. So, people began to search for substitutes which are more durable. In
4620-432: The materials of animal skins , fur , and plant materials like reed , flax , and straw , these materials were first used as clothing materials, because their dwellings were temporary, they were more likely to use the materials they used in clothing, which were easy to obtain and process. The materials of animal furs and plant products can hold a large amount of air between molecules which can create an air cavity to reduce
4697-423: The metallic enclosure can make sure that the core panel is kept in the vacuum environment. Although this material has a high thermal performance, it still maintains a high price in the last twenty years. Aerogel was first discovered by Samuel Stephens Kistle in 1931. It is a kind of gel of which the liquid component of the material is replaced by a gas, thus creating a material that is 99% air. This material has
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#17327910915074774-424: The new construction must meet the new building requirement for insulation of the Netherlands. If the renovation is of a smaller nature, the renovation directive applies. Examples of renovation are post-insulation of a cavity wall and post-insulation of a sloping roof against the roof boarding or under the tiles. Note that every renovation must meet the minimum Rc value of 1.3 W/(m ⋅K). If the current insulation has
4851-544: The particular situation. The thermal insulation requirements in the USA follow the ASHRAE 90.1 which is the U.S. energy standard for all commercial and some residential buildings. ASHRAE 90.1 standard considers multiple perspectives such as prescriptive, building envelope types and energy cost budget. And the standard has some mandatory thermal insulation requirements. All thermal insulation requirements in ASHRAE 90.1 are divided by
4928-506: The past, architects used thermal mass materials to improve thermal comfort, the heavy thermal insulation could cause the time-lag effect which might slow down the speed of heat transfer during the daytime and keep the indoor temperature in a certain range (Hot and dry climate regions usually have a large temperature difference between the day and night). The cool roof is low-cost technology based on solar reflectance and thermal emittance, which uses reflective materials and light colors to reflect
5005-551: The prevailing breezes. Reflective laminates can help reduce passive solar heat in pole barns, garages, and metal buildings. See insulated glass and quadruple glazing for discussion of windows. The thermal envelope defines the conditioned or living space in a house. The attic or basement may or may not be included in this area. Reducing airflow from inside to outside can help to reduce convective heat transfer significantly. Ensuring low convective heat transfer also requires attention to building construction ( weatherization ) and
5082-615: The properties and density of the insulation material itself are critical. Most countries have some regime of either inspections or certification of approved installers to make sure that good standards are maintained. The history of thermal insulation is not so long compared with other materials, but human beings have been aware of the importance of insulation for a long time. In the prehistoric time, human beings began their activity of making shelters against wild animals and heavy weather, human beings started their exploration of thermal insulation. Prehistoric peoples built their dwellings by using
5159-403: The quality of the air sealing of the building envelope. Smoke pencils can be used to detect gaps and caulking and weather-stripping can be used to improve air sealing. HVAC systems can ensure that a building’s air intake is both adequate, safe, and energy efficient. The thermal envelope , or heat flow control layer, is part of a building envelope but may be in a different location such as in
5236-483: The residential buildings and commercial buildings in cold climate regions such as New England and Boston. In the past time, the price of thermal insulation materials that displayed high insulated performance was very expensive. With the development of material industry and the booming of science technologies, more and more insulation materials and insulated technologies have emerged during the 20th century, which gives us various options for building insulation. Especially in
5313-482: The roof area of 0.11 to 0.18 depending on the age of the property and the type of roof construction. Newer buildings have to meet a higher standard than those built under previous versions of the regulations. It is important to realise a single R-value or U-value does not take into account the quality of construction or local environmental factors for each building. Construction quality issues can include inadequate vapor barriers and problems with draft-proofing. In addition,
5390-422: The roof covering material as a second line of defense. Domestic roof construction may also be ventilated to help remove moisture from leakage and condensation. Walls do not get as severe water exposure as roofs but still leak water. Types of wall systems with regard to water penetration are barrier , drainage and surface-sealed walls . Barrier walls are designed to allow water to be absorbed but not penetrate
5467-522: The same way. China has various climatic characters, which are divided by geographical areas. There are five climate zones in China to identify the building design include thermal insulation. (The very cold zone, cold zone, hot summer and cold winter zone, hot summer and warm winter zone and cold winter zone). Germany established its requirements of building energy efficiency in 1977, and the first energy code-the Energy Saving Ordinance (EnEV) which based on
5544-421: The solar radiation. The solar reflectance and the thermal emittance are two key factors that determine the thermal performance of the roof, and they can also improve the effectiveness of the thermal insulation since around 30% solar radiation is reflected back to the sky. The shape of the roof is also under consideration, the curved roof can receive less solar energy compared with conventional shapes. Meanwhile,
5621-403: The summer is the main question, nearly half of energy consumption in urban area is depleted by air conditioning systems to satisfy peoples' demand for thermal comfort, many developing countries in hot dry climate region suffer a shortage of electricity in the summer due to the increasing use of cooling machines. A new technology called Cool Roof has been introduced to ameliorate this situation. In
5698-408: The sun, light coloured roofing , spectrally selective (heat-reflective) paints and coatings and, various types of insulation for the rest of the envelope. Specially coated glazing can reduce SHGC to around 10%. Radiant barriers are highly effective for attic spaces in hot climates. In this application, they are much more effective in hot climates than cold climates. For downward heat flow, convection
5775-405: The use of appropriate insulation materials and design adaptations for buildings to slow the transfer of heat through the enclosure to reduce heat loss and gain. The transfer of heat is caused by the temperature difference between indoors and outdoors. Heat may be transferred either by conduction, convection, or radiation. The rate of transmission is closely related to the propagating medium. Heat
5852-446: The wall cavity which are devoid of insulation can be a source of thermal bridging. Some forms of insulation transfer heat more readily when wet, and can therefore also form a thermal bridge in this state. The heat conduction can be minimized by any of the following: reducing the cross sectional area of the bridges, increasing the bridge length, or decreasing the number of thermal bridges. One method of reducing thermal bridge effects
5929-413: The wall, and include concrete and some masonry walls. Drainage walls allow water that leaks into the wall to drain out such as cavity walls . Drainage walls may also be ventilated to aid drying such as rainscreen and pressure equalization wall systems. Sealed-surface walls do not allow any water penetration at the exterior surface of the siding material. Generally most materials will not remain sealed over
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