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Humidity
Humidity
is the amount of water vapor present in the air. Water vapor is the gaseous state of water and is invisible to the human eye.[1] Humidity
Humidity
indicates the likelihood of precipitation, dew, or fog. Higher humidity reduces the effectiveness of sweating in cooling the body by reducing the rate of evaporation of moisture from the skin. This effect is calculated in a heat index table or humidex. The amount of water vapor that is needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of water becomes lower it will eventually reach the point of saturation without adding or losing water mass. The differences in the amount of water vapor in a parcel of air can be quite large. For example, a parcel of air that is near saturation may contain 28 grams of water per cubic meter of air at 30 °C, but only 8 grams of water per cubic meter of air at 8 °C. There are three main measurements of humidity: absolute, relative and specific. Absolute humidity is the water content of air expressed in gram per cubic meter[2] or grams per kilogram[3]. Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum (highest point) for that temperature. Specific humidity is the ratio of the mass of water vapor to the total mass of the moist air parcel.

Contents

1 Types

1.1 Absolute humidity 1.2 Relative humidity 1.3 Specific humidity

2 Measurement 3 Climate

3.1 United States 3.2 Global climate

4 Air density and volume 5 Effects

5.1 Animals and plant 5.2 Human
Human
comfort 5.3 Electronics 5.4 Building construction 5.5 Industry

6 See also 7 References 8 External links

Types[edit]

Paranal Observatory
Paranal Observatory
on Cerro Paranal
Cerro Paranal
in the Atacama Desert
Atacama Desert
is one of the driest places on earth.[4]

Absolute humidity[edit] Absolute humidity is the total mass of water vapour present in a given volume or mass of air. It does not take temperature into consideration. Absolute humidity in the atmosphere ranges from near zero to roughly 30 grams per cubic meter when the air is saturated at 30 °C (86 °F).[5][6] Absolute humidity is the mass of the water vapour

(

m

H

2

O

)

displaystyle (m_ H_ 2 O )

, divided by the volume of the air and water vapor mixture

(

V

n e t

)

displaystyle (V_ net )

, which can be expressed as:

A H =

m

H

2

O

V

n e t

.

displaystyle AH= frac m_ H_ 2 O V_ net .

The absolute humidity changes as air temperature or pressure changes, if the volume is not fixed. This makes it unsuitable for chemical engineering calculations, e.g. in drying, where temperature can vary considerably. As a result, absolute humidity in chemical engineering may refer to mass of water vapor per unit mass of dry air, also known as the humidity ratio or mass mixing ratio (see "specific humidity" below), which is better suited for heat and mass balance calculations. Mass of water per unit volume as in the equation above is also defined as volumetric humidity. Because of the potential confusion, British Standard BS 1339 [7] suggests avoiding the term "absolute humidity". Units should always be carefully checked. Many humidity charts are given in g/kg or kg/kg, but any mass units may be used. The field concerned with the study of physical and thermodynamic properties of gas–vapor mixtures is named psychrometrics. Relative humidity[edit] Main article: Relative humidity The relative humidity

( R H

displaystyle (RH

or

ϕ )

displaystyle phi )

of an air-water mixture is defined as the ratio of the partial pressure of water vapor

(

p

H

2

O

)

displaystyle (p_ H_ 2 O )

in the mixture to the equilibrium vapor pressure of water

(

p

H

2

O

)

displaystyle (p_ H_ 2 O ^ * )

over a flat surface of pure water[8] at a given temperature:[9][10]

ϕ =

p

H

2

O

p

H

2

O

displaystyle phi = p_ H_ 2 O over p_ H_ 2 O ^ *

Relative humidity
Relative humidity
is normally expressed as a percentage; a higher percentage means that the air-water mixture is more humid. Relative humidity
Relative humidity
is an important metric used in weather forecasts and reports, as it is an indicator of the likelihood of precipitation, dew, or fog. In hot summer weather, a rise in relative humidity increases the apparent temperature to humans (and other animals) by hindering the evaporation of perspiration from the skin. For example, according to the Heat Index, a relative humidity of 75% at air temperature of 80.0 °F (26.7 °C) would feel like 83.6 °F ±1.3 °F (28.7 °C ±0.7 °C).[11][12] Specific humidity[edit] Specific humidity (or moisture content) is the ratio of the mass of water vapor to the total mass of the moist air parcel.[13] Specific humidity is approximately equal to the "mixing ratio", which is defined as the ratio of the mass of water vapor in an air parcel to the mass of dry air for the same parcel. As temperature decreases, the amount of water vapor needed to reach saturation also decreases. As the temperature of a parcel of air becomes lower it will eventually reach the point of saturation without adding or losing water mass. Measurement[edit]

A hygrometer

A device used to measure humidity is called a psychrometer or hygrometer. A humidistat is a humidity-triggered switch, often used to control a dehumidifier. There are various devices used to measure and regulate humidity. Calibration standards for the most accurate measurement include the gravimetric hygrometer, chilled mirror hygrometer, and electrolytic hygrometer. The gravimetric method, while the most accurate, is very cumbersome. For fast and very accurate measurement the chilled mirror method is effective.[14] For process on-line measurements, the most commonly used sensors nowadays are based on capacitance measurements to measure relative humidity[15], frequently with internal conversions to display absolute humidity as well. These are cheap, simple, generally accurate and relatively robust. All humidity sensors face problems in measuring dust-laden gas, such as exhaust streams from dryers. Humidity
Humidity
is also measured on a global scale using remotely placed satellites. These satellites are able to detect the concentration of water in the troposphere at altitudes between 4 and 12 kilometers. Satellites that can measure water vapor have sensors that are sensitive to infrared radiation. Water vapor
Water vapor
specifically absorbs and re-radiates radiation in this spectral band. Satellite
Satellite
water vapor imagery plays an important role in monitoring climate conditions (like the formation of thunderstorms) and in the development of weather forecasts. Climate[edit]

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See also: Precipitation (meteorology)
Precipitation (meteorology)
and Humid subtropical climate While humidity itself is a climate variable, it also interacts strongly with other climate variables. The humidity is affected by winds and by rainfall. The most humid cities on earth are generally located closer to the equator, near coastal regions. Cities in South and Southeast Asia
Southeast Asia
are among the most humid. Kuala Lumpur, Jakarta, and Singapore
Singapore
have very high humidity all year round because of their proximity to water bodies and the equator and often overcast weather. Some places experience extreme humidity during their rainy seasons combined with warmth giving the feel of a lukewarm sauna, such as Kolkata, Chennai and Cochin
Cochin
in India, and Lahore
Lahore
in Pakistan. Sukkur
Sukkur
city located on the Indus River
Indus River
in Pakistan
Pakistan
has some of the highest and most uncomfortable dew points in the country, frequently exceeding 30 °C (86 °F) in the Monsoon
Monsoon
season.[16] High temperatures combine with the high dew point to create heat index in excess of 65 °C (149 °F). Darwin, Australia
Darwin, Australia
experiences an extremely humid wet season from December to April. Shanghai
Shanghai
and Hong Kong
Hong Kong
also have an extreme humid period in their summer months. During the South-west and North-east Monsoon
Monsoon
seasons (respectively, late May to September and November to March), expect heavy rains and a relatively high humidity post-rainfall. Outside the monsoon seasons, humidity is high (in comparison to countries North of the Equator), but completely sunny days abound. In cooler places such as Northern Tasmania, Australia, high humidity is experienced all year due to the ocean between mainland Australia and Tasmania. In the summer the hot dry air is absorbed by this ocean and the temperature rarely climbs above 35 °C (95 °F). United States[edit] In the United States the most humid cities, strictly in terms of relative humidity, are Forks and Olympia, Washington.[17] This is because high dew points play a more significant role than relative humidity in discomfort, and so the air in these western cities usually does not feel "humid" as a result. In general, dew points are much lower in the Western U.S. than those in the Eastern U.S. The highest dew points in the US are found in coastal Florida
Florida
and Texas. When comparing Key West
Key West
and Houston, two of the most humid cities from those states, coastal Florida
Florida
seems to have the higher dew points on average. However, Houston
Houston
lacks the coastal breeze present in Key West, and, as a much larger city, it suffers from the urban heat island effect.[18] A dew point of 88 °F (31 °C) was recorded in Moorhead Minnesota
Minnesota
on July 19, 2011, with a heat index of 133.5, although dew points over 80 °F (27 °C) are rare there.[19] The US city with the lowest annual humidity is Las Vegas, Nevada, averaging 39% for a high and 21% as a low.[20] Appleton, Wisconsin registered a dew point of 90 degrees F on 13 July 1995 with an air temperature of 104 degrees resulting in a heat index of 149 degrees; this record has apparently held and in fact the highest dew point measured in the country bounced amongst or was tied by locations in Wisconsin, Minnesota, and Iowa during the preceding 70 years or more with locations in northern Illinois also coming close. Dew
Dew
points of 95 degrees are found on the Red Sea coast of Saudi Arabia at certain times. Global climate[edit] See also: Greenhouse Effect Humidity
Humidity
affects the energy budget and thereby influences temperatures in two major ways. First, water vapor in the atmosphere contains "latent" energy. During transpiration or evaporation, this latent heat is removed from surface liquid, cooling the earth's surface. This is the biggest non-radiative cooling effect at the surface. It compensates for roughly 70% of the average net radiative warming at the surface. Second, water vapor is the most abundant of all greenhouse gases. Water vapor, like a green lens that allows green light to pass through it but absorbs red light, is a "selective absorber". Along with other greenhouse gases, water vapor is transparent to most solar energy, as you can literally see. But it absorbs the infrared energy emitted (radiated) upward by the earth's surface, which is the reason that humid areas experience very little nocturnal cooling but dry desert regions cool considerably at night. This selective absorption causes the greenhouse effect. It raises the surface temperature substantially above its theoretical radiative equilibrium temperature with the sun, and water vapor is the cause of more of this warming than any other greenhouse gas. Unlike most other greenhouse gases, however, water is not merely below its boiling point in all regions of the Earth, but below its freezing point at many altitudes. As a condensible greenhouse gas, it precipitates, with a much lower scale height and shorter atmospheric lifetime- weeks instead of decades. Without other greenhouse gases, Earth's blackbody temperature, below the freezing point of water, would cause water vapor to be removed from the atmosphere.[21][22][23] Water vapor
Water vapor
is thus a "slave" to the non-condensible greenhouse gases.[24][25][26] Air density and volume[edit] Main articles: Volume (thermodynamics)
Volume (thermodynamics)
and Density
Density
of air Humidity
Humidity
depends on water vaporization and condensation, which, in turn, mainly depends on temperature. Therefore, when applying more pressure to a gas saturated with water, all components will initially decrease in volume approximately according to the ideal gas law. However, some of the water will condense until returning to almost the same humidity as before, giving the resulting total volume deviating from what the ideal gas law predicted. Conversely, decreasing temperature would also make some water condense, again making the final volume deviate from predicted by the ideal gas law. Therefore, gas volume may alternatively be expressed as the dry volume, excluding the humidity content. This fraction more accurately follows the ideal gas law. On the contrary the saturated volume is the volume a gas mixture would have if humidity was added to it until saturation (or 100% relative humidity). Humid air is less dense than dry air because a molecule of water (M ≈ 18 u) is less massive than either a molecule of nitrogen (M ≈ 28) or a molecule of oxygen (M ≈ 32). About 78% of the molecules in dry air are nitrogen (N2). Another 21% of the molecules in dry air are oxygen (O2). The final 1% of dry air is a mixture of other gases. For any gas, at a given temperature and pressure, the number of molecules present in a particular volume is constant – see ideal gas law. So when water molecules (vapor) are introduced into that volume of dry air, the number of air molecules in the volume must decrease by the same number, if the temperature and pressure remain constant. (The addition of water molecules, or any other molecules, to a gas, without removal of an equal number of other molecules, will necessarily require a change in temperature, pressure, or total volume; that is, a change in at least one of these three parameters. If temperature and pressure remain constant, the volume increases, and the dry air molecules that were displaced will initially move out into the additional volume, after which the mixture will eventually become uniform through diffusion.) Hence the mass per unit volume of the gas—its density—decreases. Isaac Newton
Isaac Newton
discovered this phenomenon and wrote about it in his book Opticks.[27] Effects[edit] Animals and plant[edit] Humidity
Humidity
is one of the fundamental abiotic factors that defines any habitat, and is a determinant of which animals and plants can thrive in a given environment.[28] The human body dissipates heat through perspiration and its evaporation. Heat convection, to the surrounding air, and thermal radiation are the primary modes of heat transport from the body. Under conditions of high humidity, the rate of evaporation of sweat from the skin decreases. Also, if the atmosphere is as warm as or warmer than the skin during times of high humidity, blood brought to the body surface cannot dissipate heat by conduction to the air. With so much blood going to the external surface of the body, less goes to the active muscles, the brain, and other internal organs. Physical strength declines, and fatigue occurs sooner than it would otherwise. Alertness and mental capacity also may be affected, resulting in heat stroke or hyperthermia. Human
Human
comfort[edit] Humans are sensitive to humid air because the human body uses evaporative cooling as the primary mechanism to regulate temperature. Under humid conditions, the rate at which perspiration evaporates on the skin is lower than it would be under arid conditions. Because humans perceive the rate of heat transfer from the body rather than temperature itself, we feel warmer when the relative humidity is high than when it is low. Some people experience difficulty breathing in humid environments. Some cases may possibly be related to respiratory conditions such as asthma, while others may be the product of anxiety. Sufferers will often hyperventilate in response, causing sensations of numbness, faintness, and loss of concentration, among others.[29] Air conditioning
Air conditioning
reduces discomfort in the summer not only by reducing temperature, but also by reducing humidity. In winter, heating cold outdoor air can decrease relative humidity levels indoor to below 30%,[30] leading to discomfort such as dry skin, cracked lips and excessive thirst. Electronics[edit] Many electronic devices have humidity specifications, for example, 5% to 45%. At the top end of the range, moisture may increase the conductivity of permeable insulators leading to malfunction. Too low humidity may make materials brittle. A particular danger to electronic items, regardless of the stated operating humidity range, is condensation. When an electronic item is moved from a cold place (e.g. garage, car, shed, an air conditioned space in the tropics) to a warm humid place (house, outside tropics), condensation may coat circuit boards and other insulators, leading to short circuit inside the equipment. Such short circuits may cause substantial permanent damage if the equipment is powered on before the condensation has evaporated. A similar condensation effect can often be observed when a person wearing glasses comes in from the cold (i.e. the glasses become foggy).[31] It is advisable to allow electronic equipment to acclimatise for several hours, after being brought in from the cold, before powering on. Some electronic devices can detect such a change and indicate, when plugged in and usually with a small droplet symbol, that they cannot be used until the risk from condensation has passed. In situations where time is critical, increasing air flow through the device's internals, such as removing the side panel from a PC case and directing a fan to blow into the case, will reduce significantly the time needed to acclimatise to the new environment. In contrast, a very low humidity level favors the build-up of static electricity, which may result in spontaneous shutdown of computers when discharges occur. Apart from spurious erratic function, electrostatic discharges can cause dielectric breakdown in solid state devices, resulting in irreversible damage. Data centers often monitor relative humidity levels for these reasons. Building construction[edit] Common construction methods often produce building enclosures with a poor thermal boundary, requiring an insulation and air barrier system designed to retain indoor environmental conditions while resisting external environmental conditions.[32] The energy-efficient, heavily sealed architecture introduced in the 20th century also sealed off the movement of moisture, and this has resulted in a secondary problem of condensation forming in and around walls, which encourages the development of mold and mildew. Additionally, buildings with foundations not properly sealed will allow water to flow through the walls due to capillary action of pores found in masonry products. Solutions for energy-efficient buildings that avoid condensation are a current topic of architecture. Industry[edit] High humidity can often have a negative effect on the capacity of chemical plants and refineries that use furnaces as part of the process (e.g. steam reforming, wet sulfuric acid process). The humidity will reduce the oxygen concentration, and the flue gas fans have to pull more air through the system to get the same firing rate (dry air is 20.9% oxygen, at 100% relative humidity the air is 20.4% oxygen).[33] See also[edit]

Dew point
Dew point
depression Humidity
Humidity
indicator Savory brittleness scale

References[edit]

^ "What is Water Vapor". Retrieved 2012-08-28.  ^ Wyer, S.S., "A treatise on producer-gas and gas-producers", (1906) The Engineering and Mining Journal, London, p.23 ^ Perry, R.H. and Green, D.W, (2007) Perry's Chemical Engineers' Handbook (8th Edition), Section 12, Psychrometry, Evaporative Cooling and Solids Drying
Drying
McGraw-Hill, ISBN 978-0-07-151135-3 ^ "Antarctic Air Visits Paranal". ESO Picture of the Week. Retrieved 4 February 2014.  ^ "Climate - Humidity
Humidity
indexes". Encyclopaedia Britannica. Retrieved 15 February 2018.  ^ "Climate/humidity table". Transport Information Service of the German Insurance Association. Retrieved 15 February 2018.  ^ British Standard
British Standard
BS 1339 (revised), Humidity
Humidity
and Dewpoint, Parts 1-3 (2002-2007) ^ "Water Vapor Myths: A Brief Tutorial".  ^ Perry, R.H. and Green, D.W, Perry's Chemical Engineers' Handbook (7th Edition), McGraw-Hill, ISBN 0-07-049841-5, Eqn 12-7 ^ Lide, David (2005). CRC Handbook of Chemistry and Physics (85 ed.). CRC Press. pp. 15–25. ISBN 0-8493-0485-7.  ^ Lans P. Rothfusz. "The Heat Index
Heat Index
'Equation' (or, More Than You Ever Wanted to Know About Heat Index)", Scientific Services Division (NWS Southern Region Headquarters), 1 July 1990 "Archived copy" (PDF). Archived from the original (PDF) on 2011-12-01. Retrieved 2011-07-23.  ^ Steadman, R. G. (July 1979). "The Assessment of Sultriness. Part I: A Temperature- Humidity
Humidity
Index Based on Human
Human
Physiology and Clothing Science". Journal of Applied Meteorology. 18 (7): 861–873. Bibcode:1979JApMe..18..861S. doi:10.1175/1520-0450(1979)018<0861:TAOSPI>2.0.CO;2.  ^ Seidel, Dian. "What is atmospheric humidity and how is it measured?". National Oceanic and Atmospheric Administration. National Oceanic and Atmospheric Administration. Retrieved 3 March 2017.  ^ Pieter R. Wiederhold. 1997. Water Vapor Measurement, Methods and Instrumentation. Marcel Dekker, New York, NY ISBN 9780824793197 ^ "BS1339" Part 3 ^ " Weather
Weather
History for Sukkur, Pakistan
Pakistan
– Weather Underground".  ^ What Is The Most Humid City In The U.S.? KOMO-TV – Seattle, Washington News Archive Archived 2007-09-29 at the Wayback Machine. ^ "USATODAY.com – Answers: Is Florida
Florida
or Texas
Texas
more humid".  ^ ""Heat Storm" (record-setting dew point of 82 at MSP, heat index tied all-time record at 119!)".  ^ "Relative Humidity
Humidity
- CityRating.com".  ^ "Blackbody Radiation".  ^ "Lecture notes".  ^ "Radiative Balance, Earth's Temperature, and Greenhouse Gases (lecture notes)".  ^ Alley, R. (2014). "GEOSC 10 Optional Enrichment Article 1".  ^ Businger, S. "Lecture 28: Future Global Warming Modeling Climate Change" (PDF). Archived from the original (PDF) on 2015-01-30.  ^ Schwieterman, E. "Comparing the Greenhouse Effect
Greenhouse Effect
on Earth, Mars, Venus, and Titan: Present Day and through Time" (PDF).  ^ Isaac Newton
Isaac Newton
(1704). Opticks. Dover. ISBN 978-0-486-60205-9.  ^ C.Michael Hogan. 2010. Abiotic factor. Encyclopedia of Earth. eds Emily Monosson and C. Cleveland. National Council for Science and the Environment Archived June 8, 2013, at the Wayback Machine.. Washington DC ^ "Heat and humidity - the lung association". www.lung.ca. Retrieved 14 March 2018.  ^ "Optimum Humidity
Humidity
Levels for Home". AirBetter.org. 3 August 2014.  ^ "Fogging Glasses".  ^ "Free publications".  ^ "Everything You Need to Know About Combustion Chemistry & Analysis – Industrial Controls". 

United States Environmental Protection Agency, "IAQ in Large Buildings". Retrieved Jan. 9, 2006.

External links[edit]

Look up humidity in Wiktionary, the free dictionary.

Wikisource
Wikisource
has the text of the 1905 New International Encyclopedia article Humidity.

Windows Program, Dewpoint Units Conversion Calculator – PhyMetrix Humidity
Humidity
Calculator – Rotronic

v t e

Meteorological data and variables

General

Adiabatic processes Advection Buoyancy Lapse rate Lightning Surface solar radiation Surface weather analysis Visibility Vorticity Wind Wind
Wind
shear

Condensation

Cloud Cloud
Cloud
condensation nuclei (CCN) Fog Convective condensation level (CCL) Lifted condensation level
Lifted condensation level
(LCL) Precipitation Water vapor

Convection

Convective available potential energy
Convective available potential energy
(CAPE) Convective inhibition
Convective inhibition
(CIN) Convective instability Convective momentum transport Convective temperature (Tc) Equilibrium level
Equilibrium level
(EL) Free convective layer
Free convective layer
(FCL) Helicity K Index Level of free convection
Level of free convection
(LFC) Lifted index
Lifted index
(LI) Maximum parcel level (MPL) Bulk Richardson number (BRN)

Temperature

Dew point
Dew point
(Td) Dew point
Dew point
depression Dry-bulb temperature Equivalent temperature (Te) Forest fire weather index Haines Index Heat index Humidex Humidity Relative humidity
Relative humidity
(RH) Mixing ratio Potential temperature (θ) Equivalent potential temperature
Equivalent potential temperature
(θe) Sea surface temperature
Sea surface temperature
(SST) Thermodynamic temperature Vapor pressure Virtual temperature Wet-bulb temperature Wet-bulb potential temperature Wind
Wind
chill

Pressure

Atmospheric pressure Baroclinity Barotropicity Pressure
Pressure
gradient Pressure-gradient force (PGF)

v t e

Heating, ventilation and air conditioning

Fundamental concepts

Air changes per hour Bake-out Building envelope Convection Dilution Domestic energy consumption Enthalpy Fluid dynamics Gas compressor Heat pump
Heat pump
and refrigeration cycle Heat transfer Humidity Infiltration Latent heat Noise control Outgassing Particulates Psychrometrics Sensible heat Stack effect Thermal comfort Thermal destratification Thermal mass Thermodynamics Vapour pressure of water

Technology

Absorption refrigerator Air barrier Air conditioning Antifreeze Automobile air conditioning Autonomous building Building insulation
Building insulation
materials Central heating Central solar heating Chilled beam Chilled water Constant air volume (CAV) Coolant Dedicated outdoor air system
Dedicated outdoor air system
(DOAS) Deep water source cooling Demand-controlled ventilation (DCV) Displacement ventilation District cooling District heating Electric heating Energy recovery ventilation (ERV) Firestop Forced-air Forced-air
Forced-air
gas Free cooling Heat recovery ventilation
Heat recovery ventilation
(HRV) Hybrid heat Hydronics HVAC Ice storage air conditioning Kitchen ventilation Mixed-mode ventilation Microgeneration Natural ventilation Passive cooling Passive house Radiant heating
Radiant heating
and cooling system Radiant cooling Radiant heating Radon mitigation Refrigeration Renewable heat Room air distribution Solar air heat Solar combisystem Solar cooling Solar heating Thermal insulation Underfloor air distribution Underfloor heating Vapor barrier Vapor-compression refrigeration
Vapor-compression refrigeration
(VCRS) Variable air volume (VAV) Variable refrigerant flow
Variable refrigerant flow
(VRF) Ventilation

Components

Air conditioner inverter Air door Air filter Air handler Air ionizer Air-mixing plenum Air purifier Air source heat pumps Automatic balancing valve Back boiler Barrier pipe Blast damper Boiler Centrifugal fan Chiller Condensate pump Condenser Condensing boiler Convection
Convection
heater Cooling tower Damper Dehumidifier Duct Economizer Electrostatic precipitator Evaporative cooler Evaporator Exhaust hood Expansion tank Fan coil unit Fan heater Fire damper Fireplace Fireplace
Fireplace
insert Freeze stat Flue Freon Fume hood Furnace Furnace
Furnace
room Gas compressor Gas heater Gasoline heater Geothermal heat pump Grease duct Grille Ground-coupled heat exchanger Heat exchanger Heat pipe Heat pump Heating film Heating system High efficiency glandless circulating pump High-efficiency particulate air
High-efficiency particulate air
(HEPA) High pressure cut off switch Humidifier Infrared
Infrared
heater Inverter compressor Kerosene heater Louver Mechanical fan Mechanical room Oil heater Packaged terminal air conditioner Plenum space Pressurisation ductwork Process duct work Radiator Radiator reflector Recuperator Refrigerant Register Reversing valve Run-around coil Scroll compressor Solar chimney Solar-assisted heat pump Space heater Smoke exhaust ductwork Thermal expansion valve Thermal wheel Thermosiphon Thermostatic radiator valve Trickle vent Trombe wall Turning vanes Ultra-low particulate air (ULPA) Whole-house fan Windcatcher Wood-burning stove

Measurement and control

Air flow meter Aquastat BACnet Blower door Building automation Carbon dioxide sensor Clean Air Delivery Rate
Clean Air Delivery Rate
(CADR) Gas sensor Home energy monitor Humidistat HVAC
HVAC
control system Intelligent buildings LonWorks Minimum efficiency reporting value (MERV) OpenTherm Programmable communicating thermostat Programmable thermostat Psychrometrics Room temperature Smart thermostat Thermostat Thermostatic radiator valve

Professions, trades, and services

Architectural acoustics Architectural engineering Architectural technologist Building services engineering Building information modeling (BIM) Deep energy retrofit Duct leakage testing Environmental engineering Hydronic balancing Kitchen exhaust cleaning Mechanical engineering Mechanical, electrical, and plumbing Mold growth, assessment, and remediation Refrigerant
Refrigerant
reclamation Testing, adjusting, balancing

Industry organizations

ACCA AMCA ASHRAE ASTM International BRE BSRIA CIBSE LEED SMACNA

Health and safety

Indoor air quality
Indoor air quality
(IAQ) Passive smoking Sick building syndrome (SBS) Volatile organic compound
Volatile organic compound
(VOC)

See also

ASHRAE
ASHRAE
Handbook Building science Fireproofing Glossary of HVAC
HVAC
terms Template:Home automation Template:Solar energy

Authority control

GND: 4125789-3 N