Room temperature, colloquially, denotes the range of air temperatures most people find comfortable indoors while dressed in typical clothing. Comfortable temperatures can be extended beyond this range depending on humidity, air circulation, and other factors.
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.
See main article: Thermal comfort. Comfort temperature is interchangeable with neutral temperature in the scientific literature, which can be calculated through regression analysis between thermal sensation votes and indoor temperature. The neutral temperature is the solution of the resulting regression model by setting the thermal sensation vote as zero. The American Heritage Dictionary of the English Language identifies room temperature as around,[1] while the Oxford English Dictionary states that it is "conventionally taken as about ".[2]
Ideal room temperature varies vastly depending on the surrounding climate. Studies from Indonesia have shown that the range of comfortable temperature is 24C29C for local residents.[3] Studies from Nigeria show a comfortable temperature range of 26C28C, comfortably cool 24C26C and comfortably warm 28C30C.[4] A field study conducted in Hyderabad, India returned a comfort band of 26C32.45C with a mean of .[5] A study conducted in Jaipur, India among healthy young men showed that the neutral thermal comfort temperature was analyzed to be, although a range of 25.9C33.8C was found.[6]
People are highly sensitive to even small differences in environmental temperature. At 24 °C, a difference of 0.38 °C can be detected between the temperature of two rooms.[7]
Owing to variations in humidity and (likely) clothing, recommendations for summer and winter may vary; a suggested typical range for summer is, with that for winter being .[8] Some studies have suggested that thermal comfort preferences of men and women may differ significantly, with women on average preferring higher ambient temperatures.[9] [10] [11]
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 while Japan in 1980 had median home temperatures of to .[12]
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.
See also: Sick building syndrome. The World Health Organization in 1987 found that comfortable indoor temperatures of 18C24C 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 of 20C was recommended. Temperatures lower than 16C with humidity above 65% were associated with respiratory hazards including allergies.[13] [14]
The WHO's 2018 guidelines give a strong recommendation that a minimum of 18C 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 21C30C depending on the region, with maximum acceptable temperatures between 25C32C.
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 20and, with excursions between 15and allowed, provided the mean kinetic temperature does not exceed .[15] The European Pharmacopoeia defines it as being simply 15to, and the Japanese Pharmacopeia defines "ordinary temperature" as 15to, with room temperature being 1to.[16] [17] Merriam-Webster gives as a medical definition a range of 15to as being suitable for human occupancy, and at which laboratory experiments are usually performed.[18]
2022-11-22. .