Room temperature

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Mercury-in-glass thermometer measuring an ambient temperature of 23 degC (73 degF) a little above the room temperature range Mercury Thermometer.jpg
Mercury-in-glass thermometer measuring an ambient temperature of 23 °C (73 °F) a little above the room temperature range

Colloquially, room temperature is a range of air temperatures that most people prefer for indoor settings. These temperatures feel comfortable to people wearing typical indoor clothing. But comfortable temperatures can be extended beyond this range depending on humidity, air circulation, and other factors.

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In certain fields, like science and engineering, and within a particular context, room temperature can mean different agreed-upon ranges. In contrast, ambient temperature is the actual temperature, as measured by a thermometer, of the air (or other medium and surroundings) in any particular place. The ambient temperature (e.g. an unheated room in winter) may be very different from an ideal room temperature.

Food or beverages may be served at "room temperature", meaning neither heated nor cooled.

Comfort temperatures

The American Heritage Dictionary of the English Language identifies room temperature as around 20–22 °C (68–72 °F), [1] while the Oxford English Dictionary states that it is "conventionally taken as about 20 °C (68 °F)". [2]

Ideal room temperature varies vastly depending on the surrounding climate. Studies from Indonesia have shown that the range of comfortable temperature falls between 24–29 °C (75–84 °F) for local residents. [3] Studies from Nigeria show a comfortable temperature range of 26–28 °C (79–82 °F), comfortably cool 24–26 °C (75–79 °F) and comfortably warm 28–30 °C (82–86 °F). [4] A field study conducted in Hyderabad, India returned a comfort band of 26–32.45 °C (79–90 °F) with a mean of 29.23 °C (85 °F). [5] A study conducted in Jaipur, India among healthy young men showed that the neutral thermal comfort temperature was analyzed to be 30.15 °C (86 °F), although a range of 25.9–33.8 °C (79–93 °F) was found. [6]

Owing to variations in humidity and (likely) clothing, recommendations for summer and winter may vary; a suggested typical range for summer is 23–25.5 °C (73–78 °F), with that for winter being 20–23.5 °C (68–74 °F). [7] Some studies have suggested that thermal comfort preferences of men and women may differ significantly, with women on average preferring higher ambient temperatures. [8] [9] [10]

In the recent past it was common for house temperatures to be kept below the comfort level; a 1978 UK study found average indoor home temperatures to be 15.8 °C (60.4 °F) while Japan in 1980 had median home temperatures of 13 °C (55 °F) to 15 °C (59 °F). [11]

Rooms may be maintained at an ambient temperature above the comfort temperature in hot weather, or below it in cold weather, if required by cost considerations or practical issues (e.g. lack of air conditioning or relatively high expense of heating.)

In the UK, the Offices, Shops and Railway Premises Act 1963 provides for a minimum temperature in commercial premises, but not for a maximum temperature.

Health effects

A digital thermometer reading an ambient temperature of 36.4degC (97degF) in an unventilated room during a heat wave; a high indoor temperature can cause heat exhaustion or heat stroke in a person. Room Temperature during Heat wave in Mexico.jpg
A digital thermometer reading an ambient temperature of 36.4°C (97°F) in an unventilated room during a heat wave; a high indoor temperature can cause heat exhaustion or heat stroke in a person.

The World Health Organization in 1987 found that comfortable indoor temperatures of between 18 and 24 °C (64 and 75 °F) were not associated with health risks for healthy adults with appropriate clothing, humidity, and other factors. For infants, elderly, and those with significant health problems, a minimum 20 °C (68 °F) was recommended. Temperatures lower than 16 °C (61 °F) with humidity above 65% were associated with respiratory hazards including allergies. [12] [13]

The WHO's 2018 guidelines give a strong recommendation that a minimum of 18 °C (64 °F) is a "safe and well-balanced indoor temperature to protect the health of general populations during cold seasons". A higher minimum temperature may be necessary for vulnerable groups including children, the elderly, and people with cardiorespiratory disease and other chronic illnesses. However, the recommendation regarding risk of exposure to high indoor temperatures is only "conditional". Minimal-risk high temperatures range from about 21 to 30 °C (70 to 86 °F) depending on the region, with maximum acceptable temperatures between 25 and 32 °C (77 and 90 °F). [14] [15]

Definitions in science and industry

Temperature ranges are defined as room temperature for certain products and processes in industry, science, standards, and consumer goods. For instance, for the shipping and storage of pharmaceuticals, the United States Pharmacopeia-National Formulary (USP-NF) defines controlled room temperature as between 20 and 25 °C (68 and 77 °F), with excursions between 15 and 30 °C (59 and 86 °F) allowed, provided the mean kinetic temperature does not exceed 25 °C (77 °F). [16] The European Pharmacopoeia defines it as being simply 15 to 25 °C (59 to 77 °F), and the Japanese Pharmacopeia defines "ordinary temperature" as 15 to 25 °C (59 to 77 °F), with room temperature being 1 to 30 °C (34 to 86 °F). [17] [18] Merriam-Webster gives as a medical definition a range of 15 to 25 °C (59 to 77 °F) as being suitable for human occupancy, and at which laboratory experiments are usually performed. [19]

See also

Related Research Articles

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Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.

<span class="mw-page-title-main">Dew point</span> Temperature at which air becomes saturated with water vapour during a cooling process

The dew point of a given body of air is the temperature to which it must be cooled to become saturated with water vapor. This temperature depends on the pressure and water content of the air. When the air is cooled below the dew point, its moisture capacity is reduced and airborne water vapor will condense to form liquid water known as dew. When this occurs through the air's contact with a colder surface, dew will form on that surface.

<span class="mw-page-title-main">Heating, ventilation, and air conditioning</span> Technology of indoor and vehicular environmental comfort

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.

<span class="mw-page-title-main">Wind chill</span> Lowering of body temperature due to the passing flow of lower-temperature air

Wind chill is the sensation of cold produced by the wind for a given ambient air temperature on exposed skin as the air motion accelerates the rate of heat transfer from the body to the surrounding atmosphere. Its values are always lower than the air temperature in the range where the formula is valid. When the apparent temperature is higher than the air temperature, the heat index is used instead.

<span class="mw-page-title-main">Indoor air quality</span> Air quality within and around buildings and structures

Indoor air quality (IAQ) is the air quality within and around buildings and structures. Poor indoor air quality due to indoor air pollution is known to affect the health, comfort, and well-being of building occupants. It has also been linked to sick building syndrome, reduced productivity, and impaired learning in schools. Common pollutants of indoor air include: secondhand tobacco smoke, air pollutants from indoor combustion, radon, molds and other allergens, carbon monoxide, volatile organic compounds, legionella and other bacteria, asbestos fibers, carbon dioxide, ozone and particulates. Source control, filtration, and the use of ventilation to dilute contaminants are the primary methods for improving indoor air quality.

<span class="mw-page-title-main">Humidex</span> Index number to describe the feeling of heat in Canada

The humidex is an index number used by Canadian meteorologists to describe how hot the weather feels to the average person, by combining the effect of heat and humidity. The term humidex was coined in 1965. The humidex is a nominally dimensionless quantity based on the dew point.

<span class="mw-page-title-main">Evaporative cooler</span> Device that cools air through the evaporation of water

An evaporative cooler is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning systems, which use vapor-compression or absorption refrigeration cycles. Evaporative cooling exploits the fact that water will absorb a relatively large amount of heat in order to evaporate. The temperature of dry air can be dropped significantly through the phase transition of liquid water to water vapor (evaporation). This can cool air using much less energy than refrigeration. In extremely dry climates, evaporative cooling of air has the added benefit of conditioning the air with more moisture for the comfort of building occupants.

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<span class="mw-page-title-main">Building science</span>

Building science is the science and technology-driven collection of knowledge in order to provide better indoor environmental quality (IEQ), energy-efficient built environments, and occupant comfort and satisfaction. Building physics, architectural science, and applied physics are terms used for the knowledge domain that overlaps with building science. In building science, the methods used in natural and hard sciences are widely applied, which may include controlled and quasi-experiments, randomized control, physical measurements, remote sensing, and simulations. On the other hand, methods from social and soft sciences, such as case study, interviews & focus group, observational method, surveys, and experience sampling, are also widely used in building science to understand occupant satisfaction, comfort, and experiences by acquiring qualitative data. One of the recent trends in building science is a combination of the two different methods. For instance, it is widely known that occupants' thermal sensation and comfort may vary depending on their sex, age, emotion, experiences, etc. even in the same indoor environment. Despite the advancement in data extraction and collection technology in building science, objective measurements alone can hardly represent occupants' state of mind such as comfort and preference. Therefore, researchers are trying to measure both physical contexts and understand human responses to figure out complex interrelationships.

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<span class="mw-page-title-main">Comfort</span> Sense of physical or psychological ease

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References

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  13. Lane, Megan (2011-03-03). "BBC News Magazine: How warm is your home". BBC News . Archived from the original on 2017-12-31.
  14. WHO 2018, p.  34: 4 Low indoor temperatures and insulation / 4.1 Guideline recommendations / ... For countries with temperate or colder climates, 18 °C has been proposed as a safe and ....
  15. WHO 2018, p.  54: 5 High indoor temperatures / 5.4 Research recommendations / Table 5.2 Research recommendations: high indoor temp / Current state of the evidence / Few high-quality studies have assessed the direct effects of indoor temperature on health..
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  17. "What are the regulatory Definitions for "Ambient", "Room Temperature" and "Cold Chain"?". ECA Academy. 2 March 2017. Retrieved 2018-04-04.
  18. Shein-Chung Chow (2007). Statistical Design and Analysis of Stability Studies. Chapman & Hall/CRC Biostatistics Series. CRC Press. p. 7. ISBN   9781584889069 . Retrieved 4 April 2018. 1.2.3.3 Definition of Room Temperature: According to the United States Pharmacopeia National Forumlary[ sic ] (USP-NF), the definition of room temperature is between 15 and 30 °C in the United States. However, in the EU, the room temperature is defined as being 15 to 25 °C, while in Japan, it is defined being 1 to 30 °C.
  19. Merriam Webster's Medical Dictionary. 2016. Archived from the original on 2010-04-10.

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