HVAC - Revision history

Jmdonev: 1 revision imported

2021-09-27T00:03:06Z

1 revision imported

← Older revision	Revision as of 00:03, 27 September 2021
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energy>Ethan.boechler at 19:52, 10 September 2021

2021-09-10T19:52:43Z

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			[[Category:Translated to French]]
			[[fr:CVC]]
	[[File:320px-Air_conditioner_armaflex_insulation.jpg\|400px\|framed\|right\|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]		[[File:320px-Air_conditioner_armaflex_insulation.jpg\|400px\|framed\|right\|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]
	<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. The term refers to a group of systems and machines used in buildings such as homes and buildings that regulate the indoor temperature and air quality to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> In Canada, the HVAC system accounts for the largest share of [[residential energy use]], but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible. Proper [[thermal insulation]] is also essential.		<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. The term refers to a group of systems and machines used in buildings such as homes and buildings that regulate the indoor temperature and air quality to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> In Canada, the HVAC system accounts for the largest share of [[residential energy use]], but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible. Proper [[thermal insulation]] is also essential.

Jmdonev: 1 revision imported

2020-04-28T15:32:43Z

1 revision imported

← Older revision	Revision as of 15:32, 28 April 2020
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energy>Jmdonev at 21:30, 13 April 2020

2020-04-13T21:30:04Z

← Older revision		Revision as of 21:30, 13 April 2020
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	[[category:371 topics]]		[[category:371 topics]]
	[[Category:Done ~~2018~~-06-01]]		[[Category:Done 2020-02-29]]
	[[File:320px-Air_conditioner_armaflex_insulation.jpg\|400px\|framed\|right\|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]		[[File:320px-Air_conditioner_armaflex_insulation.jpg\|400px\|framed\|right\|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]
	<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. The term refers to a group of systems and machines used in buildings such as homes and buildings that regulate the indoor temperature and air quality to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> In Canada, the HVAC system accounts for the largest share of [[residential energy use]], but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible. Proper [[thermal insulation]] is also essential.		<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. The term refers to a group of systems and machines used in buildings such as homes and buildings that regulate the indoor temperature and air quality to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> In Canada, the HVAC system accounts for the largest share of [[residential energy use]], but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible. Proper [[thermal insulation]] is also essential.

	[[Energy efficient building design]] has a significant impact on both [[carbon footprint]] and [[energy efficiency]]. Improving [[energy ~~intensity~~]] means making using energy efficient [[furnace]]s, [[heat pump]]s, or [[air conditioner]]s to ensure that the cost stays minimal. In addition, combining proper equipment maintenance with adequate [[thermal insulation]], [[weather stripping\|weatherization]], and [[thermostat]] settings can all work to reduce the cost of heating and cooling on energy bills.		[[Energy efficient building design]] has a significant impact on both [[carbon footprint]] and [[energy efficiency]]. Improving [[energy productivity]] means making using energy efficient [[furnace]]s, [[heat pump]]s, or [[air conditioner]]s to ensure that the cost stays minimal. In addition, combining proper equipment maintenance with adequate [[thermal insulation]], [[weather stripping\|weatherization]], and [[thermostat]] settings can all work to reduce the cost of heating and cooling on energy bills.

	==Unit Operation==		==Unit Operation==

Jmdonev: 1 revision imported: Doing upload, largely of old redirects.

2018-06-04T16:52:33Z

1 revision imported: Doing upload, largely of old redirects.

← Older revision	Revision as of 16:52, 4 June 2018
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Jmdonev at 22:07, 1 June 2018

2018-06-01T22:07:16Z

← Older revision		Revision as of 22:07, 1 June 2018
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	[[category:371 topics]]		[[category:371 topics]]
	[[Category:Done ~~2015~~-04-01]]		[[Category:Done 2018-06-01]]
	[[File:320px-Air_conditioner_armaflex_insulation.jpg\|400px\|framed\|right\|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]		[[File:320px-Air_conditioner_armaflex_insulation.jpg\|400px\|framed\|right\|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]
	<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. It refers to a group of systems and machines used in buildings such as homes and buildings that regulate the ~~internal~~ to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> ~~Generally speaking~~, the HVAC system accounts for the ~~highest~~ of energy ~~expenses~~, but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible.		<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. The term refers to a group of systems and machines used in buildings such as homes and buildings that regulate the indoor temperature and air quality to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> In Canada, the HVAC system accounts for the largest share of [[residential energy use]], but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible. Proper [[thermal insulation]] is also essential.

	~~Thus it is important to consider~~ [[~~energy~~ efficient building design]] ~~when~~ making ~~a home as well as including~~ energy efficient [[furnace]]s, heat ~~pumps~~, or air ~~conditioners~~ to ensure that the cost stays minimal. ~~As well~~, combining proper equipment maintenance with adequate [[insulation]], [[weather stripping\|weatherization]], and [[thermostat]] settings can all work to ~~cut~~ the cost of heating and cooling on energy bills.		[[Energy efficient building design]] has a significant impact on both [[carbon footprint]] and [[energy efficiency]]. Improving [[energy intensity]] means making using energy efficient [[furnace]]s, [[heat pump]]s, or [[air conditioner]]s to ensure that the cost stays minimal. In addition, combining proper equipment maintenance with adequate [[thermal insulation]], [[weather stripping\|weatherization]], and [[thermostat]] settings can all work to reduce the cost of heating and cooling on energy bills.

	==Unit Operation==		==Unit Operation==
	~~At the most basic level, an~~ HVAC system ~~works by sending~~ warmed, cooled, or otherwise treated air through a series of ducts to be distributed through rooms in a building.<ref name="CEC">Consumer Energy Center. (March 21, 2015). ''Heating and Cooling'' [Online]. Available: http://www.consumerenergycenter.org/residential/heating_cooling/heating_cooling.html</ref>		An HVAC system sends warmed, cooled, or otherwise treated air through a series of ducts to be distributed through rooms in a building.<ref name="CEC">Consumer Energy Center. (March 21, 2015). ''Heating and Cooling'' [Online]. Available: http://www.consumerenergycenter.org/residential/heating_cooling/heating_cooling.html</ref>
	===Air Conditioning===		===Air Conditioning===
	:[[Air conditioner\|''main page'']]		:[[Air conditioner\|''main page'']]
	The main goal of any [[air conditioner]] is to move cooled air from one area to another, ~~generally speaking~~ this involves taking indoor air and changing its temperature to what is comfortable and distributing this treated air around a building. Many central air conditioning units are known as "split system", as there is an outdoor ''condenser'' and an indoor ''evaporator coil'' that work to cool the house.		The main goal of any [[air conditioner]] is to move cooled air from one area to another. Generally speaking, this involves taking indoor air and changing its temperature to what is comfortable and distributing this treated air around a building. Many central air conditioning units are known as "split system", as there is an outdoor ''[[condenser]]'' and an indoor ''[[evaporator coil]]'' that work to cool the house.

	It is through a substance known as ''refrigerant'' that heat is moved around in an HVAC system. First, the outdoor unit heats the refrigerant to a high [[pressure]], high temperature [[gas]] that then condenses again into a high pressure and temperature [[liquid]]. This extremely hot liquid then flows to the indoor evaporator coil. At this point, the liquid refrigerant is allowed to expand again, turning it into a low temperature and low pressure gas. It is at this point that the cooled gas absorbs the [[heat]] from the air circulating in the building's duct work, which leaves cooler air inside to be distributed. The refrigerant gas now returns to the outdoor unit to begin the cycle again.<ref name="CEC"/> Note that the above process is a split system, also available ~~are "packaged" systems where~~ the condenser and evaporator ~~coil are held~~ in the same place.		It is through a substance known as ''[[refrigerant]]'' that heat is moved around in an HVAC system. First, the outdoor unit heats the refrigerant to a high [[pressure]], high temperature [[gas]] that then condenses again into a high pressure and temperature [[liquid]]. This extremely hot liquid then flows to the indoor evaporator coil. At this point, the liquid refrigerant is allowed to expand again, turning it into a low temperature and low pressure gas. It is at this point that the cooled gas absorbs the [[heat]] from the air circulating in the building's duct work, which leaves cooler air inside to be distributed. The refrigerant gas now returns to the outdoor unit to begin the cycle again.<ref name="CEC"/> Note that the above process is a split system. Packaged systems are also available, which have the condenser and evaporator coils in the same place.

	===Heating===		===Heating===
	Generally, homes are heated through the use of furnaces. They can also be heated naturally, and use [[passive solar heating and cooling\|passive solar heating]] to diminish energy costs. ~~As well~~, in places where a traditional furnace may not be enough, heat pumps can be installed to warm a home. The process a heat pump uses to warm a home is the reverse of what an air conditioner uses in the summer. It takes heat out of the outside air (or out of the ground if a geothermal heat pump is used) and it moves that heat inside, where it is transferred from the evaporator coil to the air circulating through ~~your~~ home.<ref name="CEC"/> More on the operation of furnaces can be found on the [[furnace]] page.		Generally, homes are heated through the use of furnaces. They can also be heated naturally, and use [[passive solar heating and cooling\|passive solar heating]] to diminish energy costs. Moreover, places where a traditional furnace may not be enough, heat pumps can be installed to warm a home. The process a heat pump uses to warm a home is the reverse of what an air conditioner uses in the summer. It takes heat out of the outside air (or out of the ground if a geothermal heat pump is used) and it moves that heat inside, where it is transferred from the evaporator coil to the air circulating through the home.<ref name="CEC"/> More on the operation of furnaces can be found on the [[furnace]] page.

	Heat pumps can also be used to cool air. When ~~they are~~ used in this manner, they operate very similarly to an air conditioner since air conditioners are simply heat pumps that only work to cool. When cooling, the heat pumps draws the warm air from inside the home and transfers it through refrigerant to the outside, expelling the extra heat and cooling the house.<ref>Natural Resources Canada. (April 28, 2015). ''What is a Heat Pump?'' [Online]. Available: https://www.nrcan.gc.ca/energy/publications/efficiency/heating-heat-pump/6827</ref>		Heat pumps can also be used to cool air. When used in this manner, they operate very similarly to an air conditioner since air conditioners are simply heat pumps that only work to cool. When cooling, the heat pumps draws the warm air from inside the home and transfers it through refrigerant to the outside, expelling the extra heat and cooling the house.<ref>Natural Resources Canada. (April 28, 2015). ''What is a Heat Pump?'' [Online]. Available: https://www.nrcan.gc.ca/energy/publications/efficiency/heating-heat-pump/6827</ref>

	[[File:HVACsys2.png\|400px\|framed\|center\|Figure 2. Diagram of HVAC system and vents in home.<ref>US Environmental Protection Agency. (May 6, 2015). ''Duct Sealing'' [Online]. Available: https://www.energystar.gov/ia/products/heat_cool/ducts/DuctSealingBrochure04.pdf</ref>]]		[[File:HVACsys2.png\|400px\|framed\|center\|Figure 2. Diagram of HVAC system and vents in home.<ref>US Environmental Protection Agency. (May 6, 2015). ''Duct Sealing'' [Online]. Available: https://www.energystar.gov/ia/products/heat_cool/ducts/DuctSealingBrochure04.pdf</ref>]]

	===Ventilation===		===Ventilation===
	All buildings need ventilation to remove stale interior air and moisture and provide fresh air to inhabitants. The ANSI standard recommends ~~that~~ houses have ~~7.5 cubic feet~~ per minute of fresh air per bedroom~~, plus one extra cubic foot with additional air flow related to the overall size of the house~~.<ref name="UKY">University of Kentucky. (March 21, 2015). ''Heating and Ventilation'' [Online]. Available: http://www.uky.edu/bae/sites/www.uky.edu.bae/files/Chapter%207%20Heating%20Ventilation%20Air%20Conditioning.pdf</ref> Natural ventilation is sometimes an option~~, as~~ simply opening windows or doors ~~can~~ increase the flow of fresh air into a home. However this can sometimes allow outdoor air with contaminants to bypass filters and permit the introduction of excess moisture and isn't always the best option.<ref name="EPA">US Environmental Protection Agency. (March 21, 2015). ''HVAC Systems'' [Online]. Available: http://www.epa.gov/iaq/schooldesign/hvac.html</ref> Therefore ~~sometimes it is best to use~~ [[forced convection\|forced ventilation]] ~~where~~ excess humidity, odors, and contaminants are replaced with outside air through spot ventilation of bathrooms and kitchens.<ref name="UKY"/> Simply put, large fans force ~~uncomfortable~~ air out through duct work and replace it with treated air. More on the function of these systems can be found on the [[forced convection\|forced ventilation]] page.		All buildings need ventilation to remove stale interior air and moisture and provide fresh air to inhabitants. The ANSI standard recommends houses have at least 200 [[liter]]s per minute of fresh air per bedroom.<ref name="UKY">University of Kentucky. (March 21, 2015). ''Heating and Ventilation'' [Online]. Available: http://www.uky.edu/bae/sites/www.uky.edu.bae/files/Chapter%207%20Heating%20Ventilation%20Air%20Conditioning.pdf</ref> Natural ventilation is sometimes an option by simply opening windows or doors to increase the flow of fresh air into a home. However, this can sometimes allow outdoor air with contaminants to bypass filters and permit the introduction of excess moisture and isn't always the best option.<ref name="EPA">US Environmental Protection Agency. (March 21, 2015). ''HVAC Systems'' [Online]. Available: http://www.epa.gov/iaq/schooldesign/hvac.html</ref> Therefore, [[forced convection\|forced ventilation]] is best wherever excess humidity, odors, and contaminants are replaced with outside air through spot ventilation of bathrooms and kitchens.<ref name="UKY"/> Simply put, large fans force the air currently in the room out through duct work and replace it with treated air. More on the function of these systems can be found on the [[forced convection\|forced ventilation]] page.

	===Air Filtration===		===Air Filtration===
	Air filtration is the last component of an HVAC system that is important. In order to control airborne particulates such as pollen, fungal spores, animal dander, insect proteins, pesticides, lead, ~~and~~ infectious bacteria and viruses from circulating around a home~~, filters are used~~. These filters are placed on ventilation systems and ducts to catch these particulates and should be regularly monitored and replaced to ensure they function correctly.<ref name="EPA"/>		Air filtration is the last component of an HVAC system that is important. Filters are used in order to control airborne particulates such as pollen, fungal spores, animal dander, insect proteins, pesticides, lead, infectious bacteria and viruses from circulating around a home. These filters are placed on ventilation systems and ducts to catch these particulates and should be regularly monitored and replaced to ensure they function correctly.<ref name="EPA"/>

			==For Further Reading==
			*[[Energy efficient building design]]
			*[[Home heating]]
			*[[Thermal insulation]]
			*[[Air conditioning]]
			*Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{reflist}}		{{reflist}}
	[[Category:Uploaded]]		[[Category:Uploaded]]

J.williams: 1 revision imported

2015-08-26T21:30:49Z

1 revision imported

← Older revision	Revision as of 21:30, 26 August 2015
(No difference)

J.williams at 16:43, 12 August 2015

2015-08-12T16:43:03Z

New page

[[category:371 topics]]
[[Category:Done 2015-04-01]]
[[File:320px-Air_conditioner_armaflex_insulation.jpg|400px|framed|right|Figure 1. The outdoor condensing portion of an air conditioning unit. The air conditioning unit is one portion of an HVAC system.<ref>"Air conditioner armaflex insulation"Licensed under CC BY 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Air_conditioner_armaflex_insulation.jpg#/media/File:Air_conditioner_armaflex_insulation.jpg</ref>]]
<onlyinclude>'''HVAC''' is an acronym for ''heating, ventilating'', and ''air conditioning''. It refers to a group of systems and machines used in buildings such as homes and buildings that regulate the internal to ensure comfort.<ref>HVAC Training 101. (March 21, 2015). ''What is HVAC?'' [Online]. Available: http://www.hvactraining101.com/what-does-HVAC-mean.html</ref> In modern homes, these three functions are often combined into one system.</onlyinclude> These systems heat and cool air to a comfortable [[temperature]], as well as providing comfortably humid air while improving air quality by bringing in fresh air. This incorporation of fresh air is particularly important in small spaces or high-odour areas.<ref name="NRCAN">Natural Resources Canada. (March 21, 2015). ''HVAC'' [Online]. Available: http://www.nrcan.gc.ca/node/6599</ref> Generally speaking, the HVAC system accounts for the highest of energy expenses, but this system is also necessary for comfort.<ref name="NRCAN"/> In 2009, 63% of Canadian residential energy use went entirely to space heating while 17% went to water heating.<ref>Natural Resources Canada Office of Energy Efficiency. (April 28, 2015). ''Energy Efficiency Trends in Canada'' [Online]. Available: http://oee.rncan.gc.ca/publications/statistics/trends11/chapter3.cfm</ref> Since space heating takes up such a large portion of all energy used, it is important to understand how to make devices that heat spaces as energy efficient as possible.

Thus it is important to consider [[energy efficient building design]] when making a home as well as including energy efficient [[furnace]]s, heat pumps, or air conditioners to ensure that the cost stays minimal. As well, combining proper equipment maintenance with adequate [[insulation]], [[weather stripping|weatherization]], and [[thermostat]] settings can all work to cut the cost of heating and cooling on energy bills.

==Unit Operation==
At the most basic level, an HVAC system works by sending warmed, cooled, or otherwise treated air through a series of ducts to be distributed through rooms in a building.<ref name="CEC">Consumer Energy Center. (March 21, 2015). ''Heating and Cooling'' [Online]. Available: http://www.consumerenergycenter.org/residential/heating_cooling/heating_cooling.html</ref>
===Air Conditioning===
:[[Air conditioner|''main page'']]
The main goal of any [[air conditioner]] is to move cooled air from one area to another, generally speaking this involves taking indoor air and changing its temperature to what is comfortable and distributing this treated air around a building. Many central air conditioning units are known as "split system", as there is an outdoor ''condenser'' and an indoor ''evaporator coil'' that work to cool the house.

It is through a substance known as ''refrigerant'' that heat is moved around in an HVAC system. First, the outdoor unit heats the refrigerant to a high [[pressure]], high temperature [[gas]] that then condenses again into a high pressure and temperature [[liquid]]. This extremely hot liquid then flows to the indoor evaporator coil. At this point, the liquid refrigerant is allowed to expand again, turning it into a low temperature and low pressure gas. It is at this point that the cooled gas absorbs the [[heat]] from the air circulating in the building's duct work, which leaves cooler air inside to be distributed. The refrigerant gas now returns to the outdoor unit to begin the cycle again.<ref name="CEC"/> Note that the above process is a split system, also available are "packaged" systems where the condenser and evaporator coil are held in the same place.

===Heating===
Generally, homes are heated through the use of furnaces. They can also be heated naturally, and use [[passive solar heating and cooling|passive solar heating]] to diminish energy costs. As well, in places where a traditional furnace may not be enough, heat pumps can be installed to warm a home. The process a heat pump uses to warm a home is the reverse of what an air conditioner uses in the summer. It takes heat out of the outside air (or out of the ground if a geothermal heat pump is used) and it moves that heat inside, where it is transferred from the evaporator coil to the air circulating through your home.<ref name="CEC"/> More on the operation of furnaces can be found on the [[furnace]] page.

Heat pumps can also be used to cool air. When they are used in this manner, they operate very similarly to an air conditioner since air conditioners are simply heat pumps that only work to cool. When cooling, the heat pumps draws the warm air from inside the home and transfers it through refrigerant to the outside, expelling the extra heat and cooling the house.<ref>Natural Resources Canada. (April 28, 2015). ''What is a Heat Pump?'' [Online]. Available: https://www.nrcan.gc.ca/energy/publications/efficiency/heating-heat-pump/6827</ref>

[[File:HVACsys2.png|400px|framed|center|Figure 2. Diagram of HVAC system and vents in home.<ref>US Environmental Protection Agency. (May 6, 2015). ''Duct Sealing'' [Online]. Available: https://www.energystar.gov/ia/products/heat_cool/ducts/DuctSealingBrochure04.pdf</ref>]]

===Ventilation===
All buildings need ventilation to remove stale interior air and moisture and provide fresh air to inhabitants. The ANSI standard recommends that houses have 7.5 cubic feet per minute of fresh air per bedroom, plus one extra cubic foot with additional air flow related to the overall size of the house.<ref name="UKY">University of Kentucky. (March 21, 2015). ''Heating and Ventilation'' [Online]. Available: http://www.uky.edu/bae/sites/www.uky.edu.bae/files/Chapter%207%20Heating%20Ventilation%20Air%20Conditioning.pdf</ref> Natural ventilation is sometimes an option, as simply opening windows or doors can increase the flow of fresh air into a home. However this can sometimes allow outdoor air with contaminants to bypass filters and permit the introduction of excess moisture and isn't always the best option.<ref name="EPA">US Environmental Protection Agency. (March 21, 2015). ''HVAC Systems'' [Online]. Available: http://www.epa.gov/iaq/schooldesign/hvac.html</ref> Therefore sometimes it is best to use [[forced convection|forced ventilation]] where excess humidity, odors, and contaminants are replaced with outside air through spot ventilation of bathrooms and kitchens.<ref name="UKY"/> Simply put, large fans force uncomfortable air out through duct work and replace it with treated air. More on the function of these systems can be found on the [[forced convection|forced ventilation]] page.

===Air Filtration===
Air filtration is the last component of an HVAC system that is important. In order to control airborne particulates such as pollen, fungal spores, animal dander, insect proteins, pesticides, lead, and infectious bacteria and viruses from circulating around a home, filters are used. These filters are placed on ventilation systems and ducts to catch these particulates and should be regularly monitored and replaced to ensure they function correctly.<ref name="EPA"/>

==References==
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