Heat on average to 19°C, recommended and approved

Minimum 18°C

In a 2018 report, the World Health Organization (WHO) said indoor housing temperatures should be "high enough to protect residents from the adverse health effects of cold weather".

For countries with temperate or colder climates, 18°C ​​has been proposed as the correct temperature during cold seasons, except for vulnerable people.

In France, a limit of 19°C on average for housing and premises, in particular businesses, is included in the energy code of 1978.

“Enduring 19°C depends on age, activity, it also depends on how you dress. It is also a spirit of solidarity, so that everyone can benefit from electricity” in a constrained context, adds Céline Laruelle, engineer at Ademe specializing in climatic equipment.

In a recent interview, the historian Renan Viguié underlined that "thermal comfort is a social construction" which began in the XNUMXth century.

"The rise in the comfort temperature, from 15 to 19 or even 20°C, accompanies the Glorious Thirties (...) Comfort is to be in a t-shirt inside when it was common in previous centuries to cover up when returning home", adds the historian.

19°C on average

The 19°C limit dates back to the first oil shocks, underlines Céline Laruelle of the French Environment and Energy Management Agency.

According to the energy code, it is an average: "when we are not there, we drop to 16-17°C and this gain can allow during the evening to be more comfortable and to heat to 20- 21°C – but not beyond”, she specifies. Derogations are provided for if elderly or young people are accommodated in the accommodation.

Ditto for offices: 19°C for occupied rooms, 16°C outside the occupation period and 8°C if the premises are unoccupied for more than two days.

The modulation can also be done by room: 17°C for a bedroom, 22 for the bathroom when it is used and the living rooms between 19 and 21 in the evening.

Violators of the rule (housing, businesses or establishments) can - in theory - be sanctioned with a fine of 1.500 euros (3.000 in the event of a repeat offence).

But today, it is "difficult to know" at what average temperature the French warm themselves. What we know is that "millions of homes are in fuel poverty, at 15°C all winter long", notes Céline Laruelle.

Minus 1°C = 7% savings

One degree less heating corresponds to 7% energy savings, according to Ademe. The impact is not negligible, heating representing more than half of the energy consumption of a dwelling (up to 66% for electric heating, a little less for oil and gas).

Electric heating (a third of French people) involves an average annual consumption of 4.312 kilowatt hours (kWh) for a house, ie a bill of around 750 euros (regulated tariff). For an apartment, it is 1.719 kWh, or 300 euros per year. Each degree less also corresponds to 7% savings on bills.

How to keep the heat?

First reflexes: close the shutters and curtains at night, avoid placing furniture or curtains in front of radiators or drying clothes there and limit air infiltration, by checking the tightness of doors and windows.

A programmable thermostat can generate 15% savings on heating, estimates Ademe.

For electric heating, it is advisable to replace old convectors with modern radiant radiators.

Installing thermometers can be useful: if you are cold when the temperature is sufficient, it is surely that the house is damp or insufficiently insulated, notes Ademe. Insulation is also the number 1 solution to reduce heating - and the bill.

On its site, the Public Health France agency also explains that in cold weather, simple actions can avoid risks. For example, you should "not overheat your home" and "make sure you have good ventilation to renew the air".