Ductwork plays a pivotal role in the efficiency and effectiveness of HVAC systems, acting as the vital conduit through which conditioned air travels to reach various parts of a building. The integrity and condition of this ductwork can significantly influence the system's overall performance, energy consumption, and indoor air quality. At the heart of optimizing HVAC efficiency lies a crucial practice: duct sealing.
Duct sealing is an often overlooked yet highly impactful process that involves closing gaps, cracks, or leaks in ductwork to prevent air from escaping or entering where it shouldn't. This simple measure can lead to considerable improvements in both HVAC efficiency and airflow.
One of the primary reasons why duct sealing enhances HVAC efficiency is by reducing energy wastage. A sudden loss of airflow might indicate Thermostat troubleshooting fast service can restore comfort in no time.. Leaky ducts can result in significant losses of heated or cooled air before it even reaches its intended destination. This means that for every unit of energy spent by your HVAC system, a portion is wasted due to leaks, forcing the system to work harder and consume more energy to maintain desired indoor temperatures. By ensuring that ducts are sealed properly, homeowners and businesses alike can drastically reduce unnecessary energy expenditure, thus lowering utility bills and mitigating environmental impact.
Moreover, improved airflow is another notable benefit of effective duct sealing. When ducts have leaks or obstructions, it disrupts the consistent flow of air throughout the entire system. This inconsistency can create uneven temperature distribution within spaces, leading to hot or cold spots that are not only uncomfortable but also indicative of inefficient system operation. Sealing ducts helps ensure that airflow remains steady and uniform across all areas serviced by the HVAC system, promoting enhanced comfort levels for occupants.
Additionally, duct sealing contributes positively to indoor air quality by preventing pollutants from entering through unsealed sections of ductwork. Unwanted particles such as dust, pollen, or even mold spores can infiltrate leaky ducts and be distributed throughout living spaces along with conditioned air. By maintaining airtight seals within duct systems, these contaminants are less likely to compromise indoor environments.
In conclusion, while often underestimated in its importance, ductwork plays an integral role in determining how efficiently an HVAC system operates. Through diligent practices like duct sealing, significant enhancements in both energy efficiency and airflow can be achieved. These improvements not only translate into cost savings but also contribute to creating healthier and more comfortable indoor environments-a testament to why proper attention should always be given to this critical aspect of HVAC management.
Understanding the causes of duct leakage is crucial when discussing why duct sealing improves HVAC efficiency and airflow. Ductwork serves as the circulatory system of a building, distributing conditioned air from heating and cooling units to various rooms. When ducts leak, this distribution is compromised, leading to inefficiencies and increased energy consumption.
One primary cause of duct leakage is poor installation. During construction or retrofitting, ducts may not be properly sealed at the joints and seams, leaving gaps that allow air to escape. Over time, these initial lapses can widen due to temperature fluctuations and vibrations in the HVAC system. Additionally, ducts made from materials susceptible to corrosion or degradation can develop holes and cracks as they age.
Another contributing factor is physical damage. Ducts running through crawl spaces or attics are prone to being inadvertently crushed or punctured by foot traffic or stored items. Animals seeking shelter can also wreak havoc on duct systems by chewing through insulation or creating nests that obstruct airflow.
Environmental factors play a significant role as well. In regions with high humidity, moisture can infiltrate ductwork, leading to rusting in metal ducts or mold growth in insulated areas. Both scenarios compromise structural integrity and air quality, prompting further leakage issues.
Now that we understand the causes of duct leakage, it becomes evident why sealing these leaks is vital for improving HVAC efficiency and airflow. By effectively sealing ducts, we ensure that conditioned air reaches its intended destination without unnecessary loss along the way. This not only enhances comfort levels within spaces but also reduces energy waste.
Sealed ducts improve HVAC efficiency by lowering the workload on heating and cooling systems. When leaks are present, systems must work harder to compensate for lost air-resulting in higher energy bills and potentially shortening equipment lifespan due to overuse.
Furthermore, addressing duct leaks enhances indoor air quality by preventing contaminants from entering the system through compromised areas. Unsealed ducts can draw in dust, allergens, and pollutants from unconditioned spaces like attics or basements; once inside the ductwork, these particles circulate throughout living areas.
In conclusion, understanding why duct sealing improves HVAC efficiency begins with recognizing common causes of leakage such as poor installation practices, physical damage over time due environmental factors among others . By addressing these issues proactively through proper maintenance techniques including thorough inspections followed up with appropriate repairs where needed , homeowners stand benefit significantly both financially via lower utility costs better overall comfort level achieved thanks efficient effective operation their entire heating cooling setup .
Duct sealing is a critical factor in improving HVAC efficiency and enhancing airflow, essentially serving as the backbone that ensures optimal performance of heating and cooling systems. At the heart of this process lies a simple yet profound principle: maintaining an airtight system to prevent energy loss. By effectively sealing ducts, homeowners can significantly reduce energy waste, ensuring that conditioned air reaches its intended destination without unnecessary loss.
The integrity of ductwork is often compromised by leaks and gaps that develop over time due to wear and tear or poor installation. These imperfections lead to decreased efficiency as conditioned air escapes into unused spaces such as attics or crawl spaces, rather than circulating throughout the home. This not only results in higher energy bills but also places additional strain on HVAC systems as they work harder to maintain desired temperatures. Sealing these leaks ensures that all generated heat or cooled air is utilized effectively, minimizing wastage and enhancing overall system performance.
Increased airflow is another significant benefit of duct sealing. When leaks are present, pressure imbalances occur within the duct system, leading to uneven distribution of air across different rooms. Some areas may receive too much airflow while others receive too little, creating uncomfortable living conditions. Proper duct sealing rectifies these imbalances by maintaining consistent pressure levels throughout the system, ensuring even distribution of air and improving comfort levels within the home.
Moreover, when ducts are sealed correctly, indoor air quality can improve substantially. Leaky ducts allow dust, allergens, and pollutants from unconditioned spaces to enter the system and circulate throughout living areas. By eliminating these entry points through effective sealing practices, homeowners can enjoy cleaner indoor environments with reduced allergens and improved respiratory health for occupants.
Environmental impact is another consideration when discussing duct sealing's benefits. Reducing energy waste through efficient airflow management helps lower carbon footprints by decreasing reliance on fossil fuels used in electricity generation for heating and cooling purposes. This contributes positively towards sustainable living goals while simultaneously benefiting homeowners financially through reduced utility costs.
In conclusion, duct sealing plays an indispensable role in enhancing HVAC efficiency by preventing energy loss and promoting balanced airflow throughout homes. By addressing leaks within ductwork systems comprehensively, homeowners can enjoy numerous benefits including lower energy bills, improved indoor comfort levels, enhanced air quality standards-and ultimately-contributing towards environmental sustainability efforts at large.
The efficiency of an HVAC system is crucial not only for maintaining a comfortable indoor environment but also for ensuring energy savings and reducing repair needs. One often overlooked aspect that significantly influences the performance of air conditioning systems is the condition of the ductwork. Properly sealed ducts can have a profound impact on both HVAC efficiency and airflow, ultimately reducing the need for frequent air conditioning repairs.
Ducts serve as the pathways through which cooled or heated air travels from your HVAC unit to various parts of your home. When these ducts are improperly sealed or have leaks, conditioned air can escape before it reaches its intended destination. This leads to energy wastage, as the HVAC system has to work harder to maintain desired temperatures, leading to increased wear and tear on its components. Over time, this strain can result in more frequent breakdowns and costly repairs.
Sealing ducts effectively closes off these leaks, ensuring that all generated conditioned air reaches its destination without unnecessary loss. This improvement in airflow means that rooms are cooled or heated more evenly and efficiently, allowing the HVAC system to operate at optimal levels. With less stress placed on the system's components due to improved airflow and reduced energy wastage, there is a significant decrease in the likelihood of malfunctions or breakdowns.
Moreover, properly sealed ducts contribute to better indoor air quality by preventing contaminants such as dust and allergens from entering through leaks. These contaminants not only affect health but can also clog filters and other parts of your HVAC system, leading to additional maintenance issues.
Investing in duct sealing offers long-term benefits beyond immediate improvements in comfort and energy savings. By reducing the strain on your air conditioning unit through enhanced efficiency and airflow, you minimize repair needs over time. This proactive approach not only extends the lifespan of your HVAC system but also ensures consistent performance throughout its operational life.
In conclusion, properly sealed ducts play a pivotal role in enhancing HVAC efficiency and improving airflow within homes. By addressing leaks within ductwork promptly, homeowners can enjoy a more effective heating and cooling experience while simultaneously reducing their reliance on costly repairs. As such, considering duct sealing as part of regular home maintenance is an investment that pays dividends in comfort, cost savings, and peace of mind.
Duct sealing is an often-overlooked aspect of home maintenance that can have a profound impact on HVAC efficiency and overall comfort. For homeowners seeking to optimize their energy usage and improve indoor air quality, understanding the cost-benefit analysis of duct sealing is essential.
At its core, duct sealing involves closing off leaks in the air ducts that are responsible for transporting heated or cooled air throughout a home. These leaks can be caused by various factors including age, poor installation, or damage over time. When ducts are not properly sealed, the conditioned air escapes into areas like attics or crawlspaces instead of reaching the intended living spaces. This inefficiency forces HVAC systems to work harder, consuming more energy and leading to increased utility bills.
One of the most compelling reasons for homeowners to invest in duct sealing is enhanced HVAC efficiency. An efficient system means that less energy is required to maintain desired temperatures within a home. Sealed ducts ensure that nearly all the conditioned air reaches the rooms it's meant for, thereby reducing the workload on heating and cooling systems. This efficiency translates into tangible savings on energy bills-often cutting costs by up to 20% according to some studies.
Beyond financial savings, duct sealing also contributes significantly to improved airflow. Leaky ducts disrupt the balance of airflow within a home which can lead to uneven heating or cooling-some rooms may feel stuffy while others remain too cold or hot. Sealing these leaks ensures consistent airflow across all rooms, enhancing comfort levels throughout the house.
Additionally, proper duct sealing addresses issues related to indoor air quality-a concern for many homeowners today. Leaks in ducts can allow dust, pollutants, and allergens from unconditioned spaces (like attics) to enter living areas through the HVAC system. By ensuring that ducts are sealed tightly, these contaminants are kept out of circulation within a home's interior environment.
While there is an upfront cost associated with professional duct sealing services-ranging anywhere from $1,000 to $2,500 depending on house size and complexity-the long-term benefits make it a worthwhile investment. The reduction in energy bills alone often recoups initial expenses within a few years. Moreover, extending the lifespan of HVAC equipment by reducing wear and tear due to overworking adds further value.
In conclusion, when evaluating whether duct sealing is worth it for your household needs, consider both immediate improvements in comfort and long-term financial savings alongside enhanced indoor air quality as key factors influencing this decision-making process. For most homeowners seeking greater efficiency from their heating or cooling systems coupled with cleaner breathable environments indoors-duct sealing emerges as an economically savvy choice offering numerous advantages beyond mere cost-effectiveness alone!
The efficiency of a heating, ventilation, and air conditioning (HVAC) system is pivotal for maintaining optimal indoor comfort while minimizing energy expenses. One often overlooked aspect that can significantly enhance HVAC performance is duct sealing. This process involves a series of meticulous steps that ensure the air circulating through the HVAC system reaches its intended destination without leakage or loss. Understanding these steps helps underline why duct sealing is integral to improving HVAC efficiency and airflow.
The initial step in professional duct sealing services involves assessing the current state of the ductwork. Technicians conduct a thorough inspection to identify any visible leaks, gaps, or disconnections within the ducts. This assessment might include using diagnostic tools such as smoke pencils or blower doors to detect less obvious leaks that could be compromising the system's efficiency. By pinpointing these vulnerabilities, professionals can devise a precise plan for sealing.
Following this evaluation, technicians proceed with cleaning the ducts if necessary.
The core step in duct sealing involves applying sealant over identified leaks and gaps. Depending on the extent of damage and accessibility of ductwork, professionals may use different materials such as mastic sealant or metal tape designed specifically for HVAC systems. Mastic is particularly favored for its durability and flexibility, effectively covering irregular surfaces around joints and seams where leaks commonly occur.
In cases where ducts are located in hard-to-reach areas like behind walls or ceilings, aerosol-based sealants may be employed. This innovative method disperses sealant into pressurized air within the system, enabling it to locate and adhere to leak sites automatically. Such techniques ensure comprehensive coverage even in complex installations.
Once all potential leak points have been sealed adequately, technicians reassess airflow using diagnostic tools again to confirm improvements in efficiency and performance post-sealing efforts. This final verification step ensures that all interventions have successfully eliminated leakage issues without inadvertently causing new problems like blocked vents due to excessive application of materials.
Duct sealing unequivocally enhances HVAC efficiency by ensuring conditioned air travels directly from source to destination without unnecessary loss along its path—a factor crucial not only for maintaining consistent temperatures across spaces but also reducing energy consumption substantially over time as less effort from heating/cooling units translates into lower utility bills overall.
In conclusion, professional duct sealing services involve a deliberate sequence aimed at maximizing an HVAC system’s potential by eliminating critical weaknesses attributable largely due either neglectful installation practices originally employed decades prior when homes were first built—or simply wear-and-tear sustained throughout years’ worth operation thereafter servicing family needs daily consistently nonstop year-round alike regardless season outside too hot cold wet dry neither here nor there whatever nature decides throw next way unrelenting challenge face headlong bravely together forevermore amen!
Geothermal heating is the direct use of geothermal energy for some heating applications. Humans have taken advantage of geothermal heat this way since the Paleolithic era. Approximately seventy countries made direct use of a total of 270 PJ of geothermal heating in 2004. As of 2007, 28 GW of geothermal heating capacity is installed around the world, satisfying 0.07% of global primary energy consumption.[1] Thermal efficiency is high since no energy conversion is needed, but capacity factors tend to be low (around 20%) since the heat is mostly needed in the winter.
Geothermal energy originates from the heat retained within the Earth since the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface.[2] Most high temperature geothermal heat is harvested in regions close to tectonic plate boundaries where volcanic activity rises close to the surface of the Earth. In these areas, ground and groundwater can be found with temperatures higher than the target temperature of the application. However, even cold ground contains heat. Below 6 metres (20 ft), the undisturbed ground temperature is consistently at the mean annual air temperature,[3] and this heat can be extracted with a ground source heat pump.
There are a wide variety of applications for cheap geothermal heat including heating of houses, greenhouses, bathing and swimming or industrial uses. Most applications use geothermal in the form of hot fluids between 50 °C (122 °F) and 150 °C (302 °F). The suitable temperature varies for the different applications. For direct use of geothermal heat, the temperature range for the agricultural sector lies between 25 °C (77 °F) and 90 °C (194 °F), for space heating lies between 50 °C (122 °F) to 100 °C (212 °F).[4] Heat pipes extend the temperature range down to 5 °C (41 °F) as they extract and "amplify" the heat. Geothermal heat exceeding 150 °C (302 °F) is typically used for geothermal power generation.[6]
In 2004 more than half of direct geothermal heat was used for space heating, and a third was used for spas.[1] The remainder was used for a variety of industrial processes, desalination, domestic hot water, and agricultural applications. The cities of Reykjavík and Akureyri pipe hot water from geothermal plants under roads and pavements to melt snow. Geothermal desalination has been demonstrated.
Geothermal systems tend to benefit from economies of scale, so space heating power is often distributed to multiple buildings, sometimes whole communities. This technique, long practiced throughout the world in locations such as Reykjavík, Iceland;[7] Boise, Idaho;[8] and Klamath Falls, Oregon;[9] is known as district heating.[10]
In Europe alone 280 geothermal district heating plants were in operation in 2016 according to the European Geothermal Energy Council (EGEC) with a total capacity of approximately 4.9 GWth.[11]
Some parts of the world, including substantial portions of the western USA, are underlain by relatively shallow geothermal resources.[12] Similar conditions exist in Iceland, parts of Japan, and other geothermal hot spots around the world. In these areas, water or steam may be captured from natural hot springs and piped directly into radiators or heat exchangers. Alternatively, the heat may come from waste heat supplied by co-generation from a geothermal electrical plant or from deep wells into hot aquifers. Direct geothermal heating is far more efficient than geothermal electricity generation and has less demanding temperature requirements, so it is viable over a large geographical range. If the shallow ground is hot but dry, air or water may be circulated through earth tubes or downhole heat exchangers which act as heat exchangers with the ground.
Steam under pressure from deep geothermal resources is also used to generate electricity from geothermal power. The Iceland Deep Drilling Project struck a pocket of magma at 2,100m. A cemented steelcase was constructed in the hole with a perforation at the bottom close to the magma. The high temperatures and pressure of the magma steam were used to generate 36MW of electricity, making IDDP-1 the world's first magma-enhanced geothermal system.[13]
In areas where the shallow ground is too cold to provide comfort directly, it is still warmer than the winter air. The thermal inertia of the shallow ground retains solar energy accumulated in the summertime, and seasonal variations in ground temperature disappear completely below 10m of depth. That heat can be extracted with a geothermal heat pump more efficiently than it can be generated by conventional furnaces.[10] Geothermal heat pumps are economically viable essentially anywhere in the world.
In theory, geothermal energy (usually cooling) can also be extracted from existing infrastructure, such as municipal water pipes.[14]
In regions without any high temperature geothermal resources, a ground-source heat pump (GSHP) can provide space heating and space cooling. Like a refrigerator or air conditioner, these systems use a heat pump to force the transfer of heat from the ground to the building. Heat can be extracted from any source, no matter how cold, but a warmer source allows higher efficiency. A ground-source heat pump uses the shallow ground or ground water (typically starting at 10–12 °C or 50–54 °F) as a source of heat, thus taking advantage of its seasonally moderate temperatures.[15] In contrast, an air source heat pump draws heat from the air (colder outside air) and thus requires more energy.
GSHPs circulate a carrier fluid (usually a mixture of water and small amounts of antifreeze) through closed pipe loops buried in the ground. Single-home systems can be "vertical loop field" systems with bore holes 50–400 feet (15–120 m) deep or,[16] if adequate land is available for extensive trenches, a "horizontal loop field" is installed approximately six feet subsurface. As the fluid circulates underground it absorbs heat from the ground and, on its return, the warmed fluid passes through the heat pump which uses electricity to extract heat from the fluid. The re-chilled fluid is sent back into the ground thus continuing the cycle. The heat extracted and that generated by the heat pump appliance as a byproduct is used to heat the house. The addition of the ground heating loop in the energy equation means that significantly more heat can be transferred to a building than if electricity alone had been used directly for heating.
Switching the direction of heat flow, the same system can be used to circulate the cooled water through the house for cooling in the summer months. The heat is exhausted to the relatively cooler ground (or groundwater) rather than delivering it to the hot outside air as an air conditioner does. As a result, the heat is pumped across a larger temperature difference and this leads to higher efficiency and lower energy use.[15]
This technology makes ground source heating economically viable in any geographical location. In 2004, an estimated million ground-source heat pumps with a total capacity of 15 GW extracted 88 PJ of heat energy for space heating. Global ground-source heat pump capacity is growing by 10% annually.[1]
Hot springs have been used for bathing at least since Paleolithic times.[17] The oldest known spa is a stone pool on China's Mount Li built in the Qin dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. Geothermal energy supplied channeled district heating for baths and houses in Pompeii around 0 AD.[18] In the first century AD, Romans conquered Aquae Sulis in England and used the hot springs there to feed public baths and underfloor heating.[19] The admission fees for these baths probably represents the first commercial use of geothermal power. A 1,000-year-old hot tub has been located in Iceland, where it was built by one of the island's original settlers.[20] The world's oldest working geothermal district heating system in Chaudes-Aigues, France, has been operating since the 14th century.[4] The earliest industrial exploitation began in 1827 with the use of geyser steam to extract boric acid from volcanic mud in Larderello, Italy.
In 1892, America's first district heating system in Boise, Idaho, was powered directly by geothermal energy, and was soon copied in Klamath Falls, Oregon in 1900. A deep geothermal well was used to heat greenhouses in Boise in 1926, and geysers were used to heat greenhouses in Iceland and Tuscany at about the same time.[21] Charlie Lieb developed the first downhole heat exchanger in 1930 to heat his house. Steam and hot water from the geysers began to be used to heat homes in Iceland in 1943.
By this time, Lord Kelvin had already invented the heat pump in 1852, and Heinrich Zoelly had patented the idea of using it to draw heat from the ground in 1912.[22] But it was not until the late 1940s that the geothermal heat pump was successfully implemented. The earliest one was probably Robert C. Webber's home-made 2.2 kW direct-exchange system, but sources disagree as to the exact timeline of his invention.[22] J. Donald Kroeker designed the first commercial geothermal heat pump to heat the Commonwealth Building (Portland, Oregon) and demonstrated it in 1946.[23][24] Professor Carl Nielsen of Ohio State University built the first residential open loop version in his home in 1948.[25] The technology became popular in Sweden as a result of the 1973 oil crisis, and has been growing slowly in worldwide acceptance since then. The 1979 development of polybutylene pipe greatly augmented the heat pump's economic viability.[23] Since 2000, a compelling body of research has been dedicated to numerically evidence the advantages and efficiency of using CO2, alternative to water, as heat transmission fluid for geothermal energy recovery from enhanced geothermal systems (EGS) where the permeability of the underground source is enhanced by hydrofracturing.[26][27] As of 2004, there are over one million geothermal heat pumps installed worldwide providing 12 GW of thermal capacity.[28] Each year, about 80,000 units are installed in the US and 27,000 in Sweden.[28]
Geothermal energy is a type of renewable energy that encourages conservation of natural resources. According to the US Environmental Protection Agency, geo-exchange systems save homeowners 30–70 percent in heating costs, and 20–50 percent in cooling costs, compared to conventional systems.[29] Geo-exchange systems also save money because they require much less maintenance. In addition to being highly reliable they are built to last for decades.
Some utilities, such as Kansas City Power and Light, offer special, lower winter rates for geothermal customers, offering even more savings.[15]
In geothermal heating projects the underground is penetrated by trenches or drillholes. As with all underground work, projects may cause problems if the geology of the area is poorly understood.
In the spring of 2007 an exploratory geothermal drilling operation was conducted to provide geothermal heat to the town hall of Staufen im Breisgau. After initially sinking a few millimeters, a process called subsidence,[30] the city center has started to rise gradually[31] causing considerable damage to buildings in the city center, affecting numerous historic houses including the town hall. It is hypothesized that the drilling perforated an anhydrite layer bringing high-pressure groundwater to come into contact with the anhydrite, which then began to expand. Currently no end to the rising process is in sight.[32][33][34] Data from the TerraSAR-X radar satellite before and after the changes confirmed the localised nature of the situation:
A geochemical process called anhydrite swelling has been confirmed as the cause of these uplifts. This is a transformation of the mineral anhydrite (anhydrous calcium sulphate) into gypsum (hydrous calcium sulphate). A pre-condition for this transformation is that the anhydrite is in contact with water, which is then stored in its crystalline structure.[35] There are other sources of potential risks, i.e.: cave enlargement or worsening of stability conditions, quality or quantity degradation of groundwater resources, Specific hazard worsening in the case of landslide-prone areas, worsening of rocky mechanical characteristics, soil and water pollution (i.e. due to antifreeze additives or polluting constructive and boring material).[36] The design defined on the base of site-specific geological, hydrogeological and environmental knowledge prevent all these potential risks.
During Roman times, warm water was circulated through open trenches to provide heating for buildings and baths in Pompeii.
Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).
HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors.
Ventilating or ventilation (the "V" in HVAC) is the process of exchanging or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and other gases. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air. Methods for ventilating a building are divided into mechanical/forced and natural types.[1]
The three major functions of heating, ventilation, and air conditioning are interrelated, especially with the need to provide thermal comfort and acceptable indoor air quality within reasonable installation, operation, and maintenance costs. HVAC systems can be used in both domestic and commercial environments. HVAC systems can provide ventilation, and maintain pressure relationships between spaces. The means of air delivery and removal from spaces is known as room air distribution.[2]
In modern buildings, the design, installation, and control systems of these functions are integrated into one or more HVAC systems. For very small buildings, contractors normally estimate the capacity and type of system needed and then design the system, selecting the appropriate refrigerant and various components needed. For larger buildings, building service designers, mechanical engineers, or building services engineers analyze, design, and specify the HVAC systems. Specialty mechanical contractors and suppliers then fabricate, install and commission the systems. Building permits and code-compliance inspections of the installations are normally required for all sizes of buildings
Although HVAC is executed in individual buildings or other enclosed spaces (like NORAD's underground headquarters), the equipment involved is in some cases an extension of a larger district heating (DH) or district cooling (DC) network, or a combined DHC network. In such cases, the operating and maintenance aspects are simplified and metering becomes necessary to bill for the energy that is consumed, and in some cases energy that is returned to the larger system. For example, at a given time one building may be utilizing chilled water for air conditioning and the warm water it returns may be used in another building for heating, or for the overall heating-portion of the DHC network (likely with energy added to boost the temperature).[3][4][5]
Basing HVAC on a larger network helps provide an economy of scale that is often not possible for individual buildings, for utilizing renewable energy sources such as solar heat,[6][7][8] winter's cold,[9][10] the cooling potential in some places of lakes or seawater for free cooling, and the enabling function of seasonal thermal energy storage. By utilizing natural sources that can be used for HVAC systems it can make a huge difference for the environment and help expand the knowledge of using different methods.
HVAC is based on inventions and discoveries made by Nikolay Lvov, Michael Faraday, Rolla C. Carpenter, Willis Carrier, Edwin Ruud, Reuben Trane, James Joule, William Rankine, Sadi Carnot, Alice Parker and many others.[11]
Multiple inventions within this time frame preceded the beginnings of the first comfort air conditioning system, which was designed in 1902 by Alfred Wolff (Cooper, 2003) for the New York Stock Exchange, while Willis Carrier equipped the Sacketts-Wilhems Printing Company with the process AC unit the same year. Coyne College was the first school to offer HVAC training in 1899.[12] The first residential AC was installed by 1914, and by the 1950s there was "widespread adoption of residential AC".[13]
The invention of the components of HVAC systems went hand-in-hand with the Industrial Revolution, and new methods of modernization, higher efficiency, and system control are constantly being introduced by companies and inventors worldwide.
Heaters are appliances whose purpose is to generate heat (i.e. warmth) for the building. This can be done via central heating. Such a system contains a boiler, furnace, or heat pump to heat water, steam, or air in a central location such as a furnace room in a home, or a mechanical room in a large building. The heat can be transferred by convection, conduction, or radiation. Space heaters are used to heat single rooms and only consist of a single unit.
Heaters exist for various types of fuel, including solid fuels, liquids, and gases. Another type of heat source is electricity, normally heating ribbons composed of high resistance wire (see Nichrome). This principle is also used for baseboard heaters and portable heaters. Electrical heaters are often used as backup or supplemental heat for heat pump systems.
The heat pump gained popularity in the 1950s in Japan and the United States.[14] Heat pumps can extract heat from various sources, such as environmental air, exhaust air from a building, or from the ground. Heat pumps transfer heat from outside the structure into the air inside. Initially, heat pump HVAC systems were only used in moderate climates, but with improvements in low temperature operation and reduced loads due to more efficient homes, they are increasing in popularity in cooler climates. They can also operate in reverse to cool an interior.
In the case of heated water or steam, piping is used to transport the heat to the rooms. Most modern hot water boiler heating systems have a circulator, which is a pump, to move hot water through the distribution system (as opposed to older gravity-fed systems). The heat can be transferred to the surrounding air using radiators, hot water coils (hydro-air), or other heat exchangers. The radiators may be mounted on walls or installed within the floor to produce floor heat.
The use of water as the heat transfer medium is known as hydronics. The heated water can also supply an auxiliary heat exchanger to supply hot water for bathing and washing.
Warm air systems distribute the heated air through ductwork systems of supply and return air through metal or fiberglass ducts. Many systems use the same ducts to distribute air cooled by an evaporator coil for air conditioning. The air supply is normally filtered through air filters[dubious – discuss] to remove dust and pollen particles.[15]
The use of furnaces, space heaters, and boilers as a method of indoor heating could result in incomplete combustion and the emission of carbon monoxide, nitrogen oxides, formaldehyde, volatile organic compounds, and other combustion byproducts. Incomplete combustion occurs when there is insufficient oxygen; the inputs are fuels containing various contaminants and the outputs are harmful byproducts, most dangerously carbon monoxide, which is a tasteless and odorless gas with serious adverse health effects.[16]
Without proper ventilation, carbon monoxide can be lethal at concentrations of 1000 ppm (0.1%). However, at several hundred ppm, carbon monoxide exposure induces headaches, fatigue, nausea, and vomiting. Carbon monoxide binds with hemoglobin in the blood, forming carboxyhemoglobin, reducing the blood's ability to transport oxygen. The primary health concerns associated with carbon monoxide exposure are its cardiovascular and neurobehavioral effects. Carbon monoxide can cause atherosclerosis (the hardening of arteries) and can also trigger heart attacks. Neurologically, carbon monoxide exposure reduces hand to eye coordination, vigilance, and continuous performance. It can also affect time discrimination.[17]
Ventilation is the process of changing or replacing air in any space to control the temperature or remove any combination of moisture, odors, smoke, heat, dust, airborne bacteria, or carbon dioxide, and to replenish oxygen. It plays a critical role in maintaining a healthy indoor environment by preventing the buildup of harmful pollutants and ensuring the circulation of fresh air. Different methods, such as natural ventilation through windows and mechanical ventilation systems, can be used depending on the building design and air quality needs. Ventilation often refers to the intentional delivery of the outside air to the building indoor space. It is one of the most important factors for maintaining acceptable indoor air quality in buildings.
Although ventilation is an integral component of maintaining good indoor air quality, it may not be satisfactory alone.[18] A clear understanding of both indoor and outdoor air quality parameters is needed to improve the performance of ventilation in terms of ...[19] In scenarios where outdoor pollution would deteriorate indoor air quality, other treatment devices such as filtration may also be necessary.[20]
Methods for ventilating a building may be divided into mechanical/forced and natural types.[21]
Mechanical, or forced, ventilation is provided by an air handler (AHU) and used to control indoor air quality. Excess humidity, odors, and contaminants can often be controlled via dilution or replacement with outside air. However, in humid climates more energy is required to remove excess moisture from ventilation air.
Kitchens and bathrooms typically have mechanical exhausts to control odors and sometimes humidity. Factors in the design of such systems include the flow rate (which is a function of the fan speed and exhaust vent size) and noise level. Direct drive fans are available for many applications and can reduce maintenance needs.
In summer, ceiling fans and table/floor fans circulate air within a room for the purpose of reducing the perceived temperature by increasing evaporation of perspiration on the skin of the occupants. Because hot air rises, ceiling fans may be used to keep a room warmer in the winter by circulating the warm stratified air from the ceiling to the floor.
Natural ventilation is the ventilation of a building with outside air without using fans or other mechanical systems. It can be via operable windows, louvers, or trickle vents when spaces are small and the architecture permits. ASHRAE defined Natural ventilation as the flow of air through open windows, doors, grilles, and other planned building envelope penetrations, and as being driven by natural and/or artificially produced pressure differentials.[1]
Natural ventilation strategies also include cross ventilation, which relies on wind pressure differences on opposite sides of a building. By strategically placing openings, such as windows or vents, on opposing walls, air is channeled through the space to enhance cooling and ventilation. Cross ventilation is most effective when there are clear, unobstructed paths for airflow within the building.
In more complex schemes, warm air is allowed to rise and flow out high building openings to the outside (stack effect), causing cool outside air to be drawn into low building openings. Natural ventilation schemes can use very little energy, but care must be taken to ensure comfort. In warm or humid climates, maintaining thermal comfort solely via natural ventilation might not be possible. Air conditioning systems are used, either as backups or supplements. Air-side economizers also use outside air to condition spaces, but do so using fans, ducts, dampers, and control systems to introduce and distribute cool outdoor air when appropriate.
An important component of natural ventilation is air change rate or air changes per hour: the hourly rate of ventilation divided by the volume of the space. For example, six air changes per hour means an amount of new air, equal to the volume of the space, is added every ten minutes. For human comfort, a minimum of four air changes per hour is typical, though warehouses might have only two. Too high of an air change rate may be uncomfortable, akin to a wind tunnel which has thousands of changes per hour. The highest air change rates are for crowded spaces, bars, night clubs, commercial kitchens at around 30 to 50 air changes per hour.[22]
Room pressure can be either positive or negative with respect to outside the room. Positive pressure occurs when there is more air being supplied than exhausted, and is common to reduce the infiltration of outside contaminants.[23]
Natural ventilation [24] is a key factor in reducing the spread of airborne illnesses such as tuberculosis, the common cold, influenza, meningitis or COVID-19. Opening doors and windows are good ways to maximize natural ventilation, which would make the risk of airborne contagion much lower than with costly and maintenance-requiring mechanical systems. Old-fashioned clinical areas with high ceilings and large windows provide the greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion. Natural ventilation requires little maintenance and is inexpensive.[25]
Natural ventilation is not practical in much of the infrastructure because of climate. This means that the facilities need to have effective mechanical ventilation systems and or use Ceiling Level UV or FAR UV ventilation systems.
Ventilation is measured in terms of Air Changes Per Hour (ACH). As of 2023, the CDC recommends that all spaces have a minimum of 5 ACH.[26] For hospital rooms with airborne contagions the CDC recommends a minimum of 12 ACH.[27] The challenges in facility ventilation are public unawareness,[28][29] ineffective government oversight, poor building codes that are based on comfort levels, poor system operations, poor maintenance, and lack of transparency.[30]
UVC or Ultraviolet Germicidal Irradiation is a function used in modern air conditioners which reduces airborne viruses, bacteria, and fungi, through the use of a built-in LED UV light that emits a gentle glow across the evaporator. As the cross-flow fan circulates the room air, any viruses are guided through the sterilization module’s irradiation range, rendering them instantly inactive.[31]
An air conditioning system, or a standalone air conditioner, provides cooling and/or humidity control for all or part of a building. Air conditioned buildings often have sealed windows, because open windows would work against the system intended to maintain constant indoor air conditions. Outside, fresh air is generally drawn into the system by a vent into a mix air chamber for mixing with the space return air. Then the mixture air enters an indoor or outdoor heat exchanger section where the air is to be cooled down, then be guided to the space creating positive air pressure. The percentage of return air made up of fresh air can usually be manipulated by adjusting the opening of this vent. Typical fresh air intake is about 10% of the total supply air.[citation needed]
Air conditioning and refrigeration are provided through the removal of heat. Heat can be removed through radiation, convection, or conduction. The heat transfer medium is a refrigeration system, such as water, air, ice, and chemicals are referred to as refrigerants. A refrigerant is employed either in a heat pump system in which a compressor is used to drive thermodynamic refrigeration cycle, or in a free cooling system that uses pumps to circulate a cool refrigerant (typically water or a glycol mix).
It is imperative that the air conditioning horsepower is sufficient for the area being cooled. Underpowered air conditioning systems will lead to power wastage and inefficient usage. Adequate horsepower is required for any air conditioner installed.
The refrigeration cycle uses four essential elements to cool, which are compressor, condenser, metering device, and evaporator.
In variable climates, the system may include a reversing valve that switches from heating in winter to cooling in summer. By reversing the flow of refrigerant, the heat pump refrigeration cycle is changed from cooling to heating or vice versa. This allows a facility to be heated and cooled by a single piece of equipment by the same means, and with the same hardware.
Free cooling systems can have very high efficiencies, and are sometimes combined with seasonal thermal energy storage so that the cold of winter can be used for summer air conditioning. Common storage mediums are deep aquifers or a natural underground rock mass accessed via a cluster of small-diameter, heat-exchanger-equipped boreholes. Some systems with small storages are hybrids, using free cooling early in the cooling season, and later employing a heat pump to chill the circulation coming from the storage. The heat pump is added-in because the storage acts as a heat sink when the system is in cooling (as opposed to charging) mode, causing the temperature to gradually increase during the cooling season.
Some systems include an "economizer mode", which is sometimes called a "free-cooling mode". When economizing, the control system will open (fully or partially) the outside air damper and close (fully or partially) the return air damper. This will cause fresh, outside air to be supplied to the system. When the outside air is cooler than the demanded cool air, this will allow the demand to be met without using the mechanical supply of cooling (typically chilled water or a direct expansion "DX" unit), thus saving energy. The control system can compare the temperature of the outside air vs. return air, or it can compare the enthalpy of the air, as is frequently done in climates where humidity is more of an issue. In both cases, the outside air must be less energetic than the return air for the system to enter the economizer mode.
Central, "all-air" air-conditioning systems (or package systems) with a combined outdoor condenser/evaporator unit are often installed in North American residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required.[32] (Minisplit ductless systems are used in these situations.) Outside of North America, packaged systems are only used in limited applications involving large indoor space such as stadiums, theatres or exhibition halls.
An alternative to packaged systems is the use of separate indoor and outdoor coils in split systems. Split systems are preferred and widely used worldwide except in North America. In North America, split systems are most often seen in residential applications, but they are gaining popularity in small commercial buildings. Split systems are used where ductwork is not feasible or where the space conditioning efficiency is of prime concern.[33] The benefits of ductless air conditioning systems include easy installation, no ductwork, greater zonal control, flexibility of control, and quiet operation.[34] In space conditioning, the duct losses can account for 30% of energy consumption.[35] The use of minisplits can result in energy savings in space conditioning as there are no losses associated with ducting.
With the split system, the evaporator coil is connected to a remote condenser unit using refrigerant piping between an indoor and outdoor unit instead of ducting air directly from the outdoor unit. Indoor units with directional vents mount onto walls, suspended from ceilings, or fit into the ceiling. Other indoor units mount inside the ceiling cavity so that short lengths of duct handle air from the indoor unit to vents or diffusers around the rooms.
Split systems are more efficient and the footprint is typically smaller than the package systems. On the other hand, package systems tend to have a slightly lower indoor noise level compared to split systems since the fan motor is located outside.
Dehumidification (air drying) in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below the dew point, moisture in the air condenses on the evaporator coil tubes. This moisture is collected at the bottom of the evaporator in a pan and removed by piping to a central drain or onto the ground outside.
A dehumidifier is an air-conditioner-like device that controls the humidity of a room or building. It is often employed in basements that have a higher relative humidity because of their lower temperature (and propensity for damp floors and walls). In food retailing establishments, large open chiller cabinets are highly effective at dehumidifying the internal air. Conversely, a humidifier increases the humidity of a building.
The HVAC components that dehumidify the ventilation air deserve careful attention because outdoor air constitutes most of the annual humidity load for nearly all buildings.[36]
All modern air conditioning systems, even small window package units, are equipped with internal air filters.[citation needed] These are generally of a lightweight gauze-like material, and must be replaced or washed as conditions warrant. For example, a building in a high dust environment, or a home with furry pets, will need to have the filters changed more often than buildings without these dirt loads. Failure to replace these filters as needed will contribute to a lower heat exchange rate, resulting in wasted energy, shortened equipment life, and higher energy bills; low air flow can result in iced-over evaporator coils, which can completely stop airflow. Additionally, very dirty or plugged filters can cause overheating during a heating cycle, which can result in damage to the system or even fire.
Because an air conditioner moves heat between the indoor coil and the outdoor coil, both must be kept clean. This means that, in addition to replacing the air filter at the evaporator coil, it is also necessary to regularly clean the condenser coil. Failure to keep the condenser clean will eventually result in harm to the compressor because the condenser coil is responsible for discharging both the indoor heat (as picked up by the evaporator) and the heat generated by the electric motor driving the compressor.
HVAC is significantly responsible for promoting energy efficiency of buildings as the building sector consumes the largest percentage of global energy.[37] Since the 1980s, manufacturers of HVAC equipment have been making an effort to make the systems they manufacture more efficient. This was originally driven by rising energy costs, and has more recently been driven by increased awareness of environmental issues. Additionally, improvements to the HVAC system efficiency can also help increase occupant health and productivity.[38] In the US, the EPA has imposed tighter restrictions over the years. There are several methods for making HVAC systems more efficient.
In the past, water heating was more efficient for heating buildings and was the standard in the United States. Today, forced air systems can double for air conditioning and are more popular.
Some benefits of forced air systems, which are now widely used in churches, schools, and high-end residences, are
A drawback is the installation cost, which can be slightly higher than traditional HVAC systems.
Energy efficiency can be improved even more in central heating systems by introducing zoned heating. This allows a more granular application of heat, similar to non-central heating systems. Zones are controlled by multiple thermostats. In water heating systems the thermostats control zone valves, and in forced air systems they control zone dampers inside the vents which selectively block the flow of air. In this case, the control system is very critical to maintaining a proper temperature.
Forecasting is another method of controlling building heating by calculating the demand for heating energy that should be supplied to the building in each time unit.
Ground source, or geothermal, heat pumps are similar to ordinary heat pumps, but instead of transferring heat to or from outside air, they rely on the stable, even temperature of the earth to provide heating and air conditioning. Many regions experience seasonal temperature extremes, which would require large-capacity heating and cooling equipment to heat or cool buildings. For example, a conventional heat pump system used to heat a building in Montana's −57 °C (−70 °F) low temperature or cool a building in the highest temperature ever recorded in the US—57 °C (134 °F) in Death Valley, California, in 1913 would require a large amount of energy due to the extreme difference between inside and outside air temperatures. A metre below the earth's surface, however, the ground remains at a relatively constant temperature. Utilizing this large source of relatively moderate temperature earth, a heating or cooling system's capacity can often be significantly reduced. Although ground temperatures vary according to latitude, at 1.8 metres (6 ft) underground, temperatures generally only range from 7 to 24 °C (45 to 75 °F).
Photovoltaic solar panels offer a new way to potentially decrease the operating cost of air conditioning. Traditional air conditioners run using alternating current, and hence, any direct-current solar power needs to be inverted to be compatible with these units. New variable-speed DC-motor units allow solar power to more easily run them since this conversion is unnecessary, and since the motors are tolerant of voltage fluctuations associated with variance in supplied solar power (e.g., due to cloud cover).
Energy recovery systems sometimes utilize heat recovery ventilation or energy recovery ventilation systems that employ heat exchangers or enthalpy wheels to recover sensible or latent heat from exhausted air. This is done by transfer of energy from the stale air inside the home to the incoming fresh air from outside.
The performance of vapor compression refrigeration cycles is limited by thermodynamics.[39] These air conditioning and heat pump devices move heat rather than convert it from one form to another, so thermal efficiencies do not appropriately describe the performance of these devices. The Coefficient of performance (COP) measures performance, but this dimensionless measure has not been adopted. Instead, the Energy Efficiency Ratio (EER) has traditionally been used to characterize the performance of many HVAC systems. EER is the Energy Efficiency Ratio based on a 35 °C (95 °F) outdoor temperature. To more accurately describe the performance of air conditioning equipment over a typical cooling season a modified version of the EER, the Seasonal Energy Efficiency Ratio (SEER), or in Europe the ESEER, is used. SEER ratings are based on seasonal temperature averages instead of a constant 35 °C (95 °F) outdoor temperature. The current industry minimum SEER rating is 14 SEER. Engineers have pointed out some areas where efficiency of the existing hardware could be improved. For example, the fan blades used to move the air are usually stamped from sheet metal, an economical method of manufacture, but as a result they are not aerodynamically efficient. A well-designed blade could reduce the electrical power required to move the air by a third.[40]
Demand-controlled kitchen ventilation (DCKV) is a building controls approach to controlling the volume of kitchen exhaust and supply air in response to the actual cooking loads in a commercial kitchen. Traditional commercial kitchen ventilation systems operate at 100% fan speed independent of the volume of cooking activity and DCKV technology changes that to provide significant fan energy and conditioned air savings. By deploying smart sensing technology, both the exhaust and supply fans can be controlled to capitalize on the affinity laws for motor energy savings, reduce makeup air heating and cooling energy, increasing safety, and reducing ambient kitchen noise levels.[41]
Air cleaning and filtration removes particles, contaminants, vapors and gases from the air. The filtered and cleaned air then is used in heating, ventilation, and air conditioning. Air cleaning and filtration should be taken in account when protecting our building environments.[42] If present, contaminants can come out from the HVAC systems if not removed or filtered properly.
Clean air delivery rate (CADR) is the amount of clean air an air cleaner provides to a room or space. When determining CADR, the amount of airflow in a space is taken into account. For example, an air cleaner with a flow rate of 30 cubic metres (1,000 cu ft) per minute and an efficiency of 50% has a CADR of 15 cubic metres (500 cu ft) per minute. Along with CADR, filtration performance is very important when it comes to the air in our indoor environment. This depends on the size of the particle or fiber, the filter packing density and depth, and the airflow rate.[42]
Poorly maintained air conditioners/ventilation systems can harbor mold, bacteria, and other contaminants, which are then circulated throughout indoor spaces, contributing to ...[43]
The HVAC industry is a worldwide enterprise, with roles including operation and maintenance, system design and construction, equipment manufacturing and sales, and in education and research. The HVAC industry was historically regulated by the manufacturers of HVAC equipment, but regulating and standards organizations such as HARDI (Heating, Air-conditioning and Refrigeration Distributors International), ASHRAE, SMACNA, ACCA (Air Conditioning Contractors of America), Uniform Mechanical Code, International Mechanical Code, and AMCA have been established to support the industry and encourage high standards and achievement. (UL as an omnibus agency is not specific to the HVAC industry.)
The starting point in carrying out an estimate both for cooling and heating depends on the exterior climate and interior specified conditions. However, before taking up the heat load calculation, it is necessary to find fresh air requirements for each area in detail, as pressurization is an important consideration.
ISO 16813:2006 is one of the ISO building environment standards.[44] It establishes the general principles of building environment design. It takes into account the need to provide a healthy indoor environment for the occupants as well as the need to protect the environment for future generations and promote collaboration among the various parties involved in building environmental design for sustainability. ISO16813 is applicable to new construction and the retrofit of existing buildings.[45]
The building environmental design standard aims to:[45]
In the United States, federal licensure is generally handled by EPA certified (for installation and service of HVAC devices).
Many U.S. states have licensing for boiler operation. Some of these are listed as follows:
Finally, some U.S. cities may have additional labor laws that apply to HVAC professionals.
Many HVAC engineers are members of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). ASHRAE regularly organizes two annual technical committees and publishes recognized standards for HVAC design, which are updated every four years.[56]
Another popular society is AHRI, which provides regular information on new refrigeration technology, and publishes relevant standards and codes.
Codes such as the UMC and IMC do include much detail on installation requirements, however. Other useful reference materials include items from SMACNA, ACGIH, and technical trade journals.
American design standards are legislated in the Uniform Mechanical Code or International Mechanical Code. In certain states, counties, or cities, either of these codes may be adopted and amended via various legislative processes. These codes are updated and published by the International Association of Plumbing and Mechanical Officials (IAPMO) or the International Code Council (ICC) respectively, on a 3-year code development cycle. Typically, local building permit departments are charged with enforcement of these standards on private and certain public properties.
An HVAC technician is a tradesman who specializes in heating, ventilation, air conditioning, and refrigeration. HVAC technicians in the US can receive training through formal training institutions, where most earn associate degrees. Training for HVAC technicians includes classroom lectures and hands-on tasks, and can be followed by an apprenticeship wherein the recent graduate works alongside a professional HVAC technician for a temporary period.[57] HVAC techs who have been trained can also be certified in areas such as air conditioning, heat pumps, gas heating, and commercial refrigeration.
The Chartered Institution of Building Services Engineers is a body that covers the essential Service (systems architecture) that allow buildings to operate. It includes the electrotechnical, heating, ventilating, air conditioning, refrigeration and plumbing industries. To train as a building services engineer, the academic requirements are GCSEs (A-C) / Standard Grades (1-3) in Maths and Science, which are important in measurements, planning and theory. Employers will often want a degree in a branch of engineering, such as building environment engineering, electrical engineering or mechanical engineering. To become a full member of CIBSE, and so also to be registered by the Engineering Council UK as a chartered engineer, engineers must also attain an Honours Degree and a master's degree in a relevant engineering subject.[citation needed] CIBSE publishes several guides to HVAC design relevant to the UK market, and also the Republic of Ireland, Australia, New Zealand and Hong Kong. These guides include various recommended design criteria and standards, some of which are cited within the UK building regulations, and therefore form a legislative requirement for major building services works. The main guides are:
Within the construction sector, it is the job of the building services engineer to design and oversee the installation and maintenance of the essential services such as gas, electricity, water, heating and lighting, as well as many others. These all help to make buildings comfortable and healthy places to live and work in. Building Services is part of a sector that has over 51,000 businesses and employs represents 2–3% of the GDP.
The Air Conditioning and Mechanical Contractors Association of Australia (AMCA), Australian Institute of Refrigeration, Air Conditioning and Heating (AIRAH), Australian Refrigeration Mechanical Association and CIBSE are responsible.
Asian architectural temperature-control have different priorities than European methods. For example, Asian heating traditionally focuses on maintaining temperatures of objects such as the floor or furnishings such as Kotatsu tables and directly warming people, as opposed to the Western focus, in modern periods, on designing air systems.
The Philippine Society of Ventilating, Air Conditioning and Refrigerating Engineers (PSVARE) along with Philippine Society of Mechanical Engineers (PSME) govern on the codes and standards for HVAC / MVAC (MVAC means "mechanical ventilation and air conditioning") in the Philippines.
The Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE) was established to promote the HVAC industry in India. ISHRAE is an associate of ASHRAE. ISHRAE was founded at New Delhi[58] in 1981 and a chapter was started in Bangalore in 1989. Between 1989 & 1993, ISHRAE chapters were formed in all major cities in India.[citation needed]
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