Room temperature

Mercury-in-glass thermometer for measurement of room temperature

Room temperature is a colloquial expression for the typical or preferred indoor (climate-controlled) temperature to which people are generally accustomed. It represents the small range of temperatures at which the air feels neither hot nor cold, approximately 24 °C (75 °F).

Comfort levels

The American Heritage Dictionary of the English Language identifies room temperature as around 20 to 22 °C (68 to 72 °F).

Owing to variations in humidity and likely clothing, recommendations for summer and winter may vary; a suggested typical range for summer is 23 °C (73 °F) to 25.5 °C (78 °F), with that for winter being 20 °C (68 °F) to 23.5 °C (74 °F). Although by other considerations the maximum should be below 24 °C (75 °F) – and for sick building syndrome avoidance, below 22 °C (72 °F).

According to the West Midlands Public Health Observatory (UK), an adequate level of wintertime warmth is 21 °C (70 °F) for a living room, and a minimum of 18 °C (64 °F) for other occupied rooms, giving 24 °C (75 °F) as a maximum comfortable room temperature for sedentary adults. At temperatures below 20 °C (68 °F), increased risk of death has been observed, and winter deaths reportedly rise at a rate of about 1.4% per degree below 18 °C (64 °F).

Ambient versus room temperature

Room temperature implies a temperature inside a temperature-controlled building. Ambient temperature simply means "the temperature of the surroundings" and will be the same as room temperature indoors. In many languages, such as Spanish, Portuguese and Italian, there is an expression for ambient temperature, but no distinct translation for room temperature.