Everyday action · tip no. 4
Heat your home to 19 °C: save energy without feeling cold
Heating accounts for the largest share of the energy used in a home. According to ADEME, lowering the temperature by one degree cuts heating consumption by about 7%. A practical guide to a comfortable, low-energy winter.
According to ADEME, the French agency for ecological transition, heating accounts for about two-thirds of the energy used in a home in France. It is therefore the first thing to tackle at home. The basic rule is simple: heat living areas to 19 °C (about 66 °F) and bedrooms a little less. According to ADEME, every degree lower cuts heating consumption by about 7%. But temperature is only part of the answer: programming, ventilation, insulation and the choice of heating system matter just as much.
Why heating weighs so heavily
Winter lasts a long time
In mainland France, the heating season usually lasts several months, often from October to April. Throughout this period, you constantly have to make up for the heat escaping from the home through the walls, roof, windows, floor and the air being renewed.
Fossil fuels
Many French homes are still heated with gas or heating oil. Burning these fossil fuels releases CO₂. A poorly insulated home heated with oil can emit several tonnes of CO₂ a year. Electric heating emits far less in France, because electricity there is largely produced by nuclear power and renewables, but it remains expensive and puts pressure on the grid during cold spells.
Heat leaks
In an old, unrenovated home, a large share of the heat escapes through the roof, walls and windows. Turning the heating up only feeds these leaks.
What the data say
- 19 °C in living areas: this is the daytime temperature recommended by ADEME when you are at home. French energy law also sets an average limit of 19 °C for heating homes and premises.
- 16 to 17 °C at night and in bedrooms: people sleep better in a cool room, and under a duvet a lower temperature is perfectly comfortable.
- About 7% saving per degree: according to ADEME, lowering the thermostat by 1 °C cuts heating consumption by about 7%. Going from 21 °C to 19 °C therefore saves around 14%, on the bill and on emissions.
- Up to 10% more with programming: according to ADEME, a programmable thermostat that automatically lowers the temperature at night and when you are out can save up to about 10% more.
How to do it in practice
1. Set the right temperature, room by room
- Living areas (living room, office): 19 °C when you are there.
- Bedrooms: 16 to 17 °C.
- Bathroom: a little warmer, only when you are using it.
- Unused rooms: heating at minimum, on frost-protection mode if they are not used.
What counts is the average across the home: one room can be slightly warmer if others are cooler.
2. Program your heating
A programmable or smart thermostat automatically lowers the temperature at night and while you are out, then raises it before you return. For an absence of several days, switch to frost-protection mode (about 8 °C). There is no need to switch the heating off completely for a short absence in a very poorly insulated home, at the risk of damp: a low setting is enough.
3. Ventilate wisely
Ventilation is essential for health and to prevent damp, which makes the air feel colder and encourages mould. The right method: open the windows wide for 5 to 10 minutes a day, with the heating off in that room, rather than leaving a window ajar for hours. Never block air vents or ventilation outlets.
4. Keep the heat inside
- Close shutters and curtains at nightfall.
- Do not put furniture or curtains in front of radiators.
- Fit draught excluders on doors and seals on leaky windows.
- Dust your radiators and have your boiler serviced every year, as French law requires for boilers.
5. Dress for winter
A jumper, warm socks or a throw on the sofa will make you feel comfortable at 19 °C. It is the simplest and cheapest action of all.
6. Think about insulation and a heat pump
If your home is poorly insulated, that is where the biggest gains lie. Insulating the loft, often the cheapest and most cost-effective step, then the walls, and replacing the oldest windows can sharply reduce consumption. Replacing an oil or gas boiler with a heat pump or a district heating connection further reduces emissions per kilowatt-hour.
In France, public grants help finance this work, and the public service France Rénov' offers free, independent advice to plan your project. Many other countries have similar schemes. If you rent, talk to your landlord: in France, the most energy-inefficient homes are subject to gradual renovation requirements.
Misconceptions to avoid
- "Turning the heating off and then back on full uses more than leaving it on." In most cases, this is false: lowering the temperature while you are out always saves energy. You just need to avoid going too low in a damp home.
- "Electric heating doesn't pollute." In France, it emits little CO₂, but it weighs on your bill and on the electricity grid in winter. Saving electricity is still worthwhile.
- "At 19 °C, you're bound to feel cold." How warm you feel also depends on humidity, draughts and the temperature of the walls. A well-ventilated home without draughts is comfortable at 19 °C.
In short
- Heating accounts for about two-thirds of the energy used in a home.
- 19 °C in living areas, 16 to 17 °C in bedrooms: this is ADEME's recommendation.
- Every degree lower cuts heating consumption by about 7%.
- Programming, short airing, shutters closed at night and, where possible, insulation: these are the actions that count most.