What is the ideal room temperature? To determine it, several factors, such as age or the part concerned, must be taken into account. We take stock.
Our brain works hard to ensure that our body maintains an average body temperature of around 37°C. If the environment is too cold, it will force our body to burn glucose to warm us up. Conversely, our body will sweat if the outside temperature is too hot.
The ideal room temperature could therefore be defined as the one that minimizes as much as possible the efforts of our brain to maintain our body temperature. Roughly speaking, at this temperature, a person ultimately feels neither hot nor cold when wearing ordinary indoor clothes.
Actually, there is no fixed value. According to the American Heritage Dictionary, the room temperature is somewhere between 20 to 22°C, while the Oxford English Dictionary sets a temperature of around 20°C. For its part, the World Health Organization (WHO) proposes a minimum of 18°C for people in good health and warmly dressed, and a temperature of 20°C for the very old, very young or suffering from a disease.
We must also take into account the environment in which we operate. The Ecological Transition Agency lists some guidelines to follow depending on the room in which we find ourselves. For living spaces such as the living room or dining room, an ideal temperature of 19°C is proposed. . Obviously, this varies according to our age and state of health. Elderly people, for example, will be more comfortable with a temperature between 20 and 22°C.
In the bedroom, we know that excessive temperature can affect our sleep. Also ADEME recommends a temperature not exceeding 17°C . Generally speaking, a bedroom can be 1-2 degrees colder than the rest of the house. The bathroom, on the other hand, should be 1 to 2 degrees warmer, so that you are comfortable enough when you get out of a shower or a bath. ADEME recommends a temperature of 22°C .
Unsurprisingly, most people aren't happy with their thermal comfort at work. A 2015 survey of office workers in the United States found that 42% found their offices too hot in the summer, and 56% found them too cold in the winter.
And this can have many consequences. In the UK, for example, a study has shown that up to 2% of office hours are wasted by people fighting over temperature levels, costing the economy almost 15 billion dollars per year .
The effects on productivity are also important. A study published in 2005 tracked the activity of several office workers of an insurance company to measure the impact of temperature on their efficiency. With a temperature of 25°C, the error rate was 10%. When the temperature dropped five degrees, they were half as productive. Another study also showed that warmer conditions induced greater social closeness and the use of more concrete language.
There is even a gender bias when it comes to thermal comfort. Most office buildings set values based on a decades-old formula that uses human metabolic rates to calculate the ideal room temperature. However, women have a different metabolism that favors warmer ambient temperatures than those of men.
In one study, researchers placed over 500 German students in a room to take tests at different temperatures, ranging from 16°C to 32°C . The authors then highlighted a difference in performance between men and women based on experience.
"As the temperature rose, women performed better in math and verbal tasks, while men performed worse." The increase in women's performance in these same tasks was also much more pronounced than the decrease in men's performance" , said Tom Chang, co-author of this work.
Basically, the warmer the room, the more efficient women will be (and vice versa for men).
