What temperature should I choose for my heating system?

Temperatures recommended by ADEME and experts

The Agence de l'Environnement et de la Maîtrise de l'Énergie (ADEME - French Environment and Energy Management Agency) has drawn up clear recommendations concerning the ideal temperatures for each type of space in a dwelling. These recommendations are based on scientific studies combining thermal comfort, health and energy efficiency.

The reference temperature for living areas is 19°C. This value may seem cool to some, but it represents the best compromise between well-being and energy consumption. It's important to understand that our perception of temperature is influenced by many factors: humidity, draughts, insulation and even our level of activity.

For bedrooms, the ideal temperature is 16-17°C. This nocturnal freshness promotes better quality sleep. Sleep studies have shown that our bodies naturally lower their body temperature during the night, and that an overheated bedroom disrupts this natural process. However, for the bedrooms of babies and toddlers, we recommend 18-20°C, as their thermoregulatory systems are still immature.

The bathroom is a notable exception. During use, particularly in the shower or bath, a temperature of 22°C is recommended to avoid thermal shock. When not in use, however, we recommend lowering the heating to 17°C.

The impact of a degree on your energy bill

Understanding the financial impact of each additional degree is essential to making informed choices. The often-quoted rule is simple but telling: each additional degree increases your energy consumption by 7%. This increase may seem modest, but it translates into significant sums over a full year.

Let's take a concrete example: for an average French household spending 1,500 euros a year on heating, going from 19°C to 21°C throughout the home represents an increase of 14%, or around 210 additional euros a year. Over ten years, this represents more than 2,000 euros, not counting energy price inflation.

This economic reality takes on particular importance in the current context of rising energy prices. Natural gas and electricity prices have risen sharply in recent years, making temperature control even more crucial to household budgets.

It's also important to consider the environmental aspect. Reducing your heating temperature by one or two degrees contributes directly to reducing your carbon footprint. In a 100 m² home, maintaining a temperature of 19°C rather than 21°C avoids the emission of around 300 kg of CO2 per year, the equivalent of 1,500 km driven by car.

Adapt the temperature to the different rooms in your home

Each room in your home has a different function and therefore deserves special attention when it comes to optimum temperature. This differentiated heating approach, also known as thermal zoning, optimizes both comfort and energy savings.

Living room and living spaces

The living room is where you spend most of your waking hours. The temperature of 19°C remains the benchmark, but it can be adjusted to suit your needs. If you have elderly people or people with reduced mobility in your household, 20°C may be more appropriate, as their metabolism generates less body heat.

The layout of your living room also influences the perception of temperature. A sofa next to a poorly insulated window will feel cold even if the thermostat reads 19°C. The use of thermal curtains, thick carpets and strategic furniture placement can significantly improve thermal comfort without increasing heating.

The kitchen: a room that warms up naturally

The kitchen naturally generates heat during use. Ovens, hobs and even household appliances such as refrigerators give off heat. So it's a good idea to set the heating in this room to 18°C, or even lower if you cook regularly.

This approach delivers substantial savings, especially in kitchens that open onto the living room, where cooking heat naturally spreads to adjacent spaces. Some households find they can turn off the kitchen heating completely during important cooking operations.

Bedrooms: freshness for a better night's sleep

As mentioned above, rooms should be kept between 16 and 17°C. This freshness may seem uncomfortable at first, but the benefits in terms of sleep quality are real and measurable. Sleep science shows that a slightly lower body temperature makes it easier to fall asleep and improves the quality of deep sleep.

To compensate for this lower temperature, invest in good bedding: a comforter adapted to the season (tog rating of 10-13 for winter), sheets in natural materials like cotton or linen, and possibly a hot water bottle to pre-warm the bed. These elements considerably increase comfort without the need for additional heating.

For children's and babies' rooms, the temperature should be slightly higher, around 18-20°C. Young children have more difficulty regulating their body temperature, and it's essential to prevent them from getting too cold at night. Use a room thermometer to monitor the temperature and adjust the sleeping bag or blanket accordingly.

The home office: comfort and productivity

With the development of telecommuting, many households have set up a home office. This room requires special attention, as you spend long hours in a seated position, with minimal physical activity. The recommended temperature is between 19 and 20°C.

If your office is underheated, your productivity and concentration can suffer. Studies have shown that too low a temperature in a workspace increases errors and reduces the speed of task execution. Conversely, an overheated office causes drowsiness and mental fatigue.

Entrance and corridors: circulation areas

Entrances, corridors and other circulation areas don't need to be heated to the same temperature as living rooms. A temperature of 17°C is more than sufficient, as you'll only be in it for a few minutes at a time. This buffer zone also reduces heat loss to the outside.

Beware, however, of the corridors that lead to the bedrooms: if they're too cold, this can create discomfort when moving around at night, especially for children or the elderly.

Common mistakes to avoid

Many misconceptions and bad practices persist when it comes to home heating. Identifying and correcting these errors can generate significant savings while improving your comfort.

Turn up the thermostat for faster heating

This is probably the most common mistake. Many people think that setting the thermostat to 25°C will heat the house faster than setting it to 19°C. This is not true. Your heating system operates at maximum power, regardless of the temperature required, until the setpoint is reached. The only difference is that you risk forgetting to turn down the thermostat and unnecessarily overheating your home.

Turn off the heating completely when you leave

Contrary to popular belief, turning off the heating completely when you leave your home for several hours is not necessarily the most economical solution. Your system will have to consume a lot of energy to heat a completely cooled home. It's best to lower the temperature by 3-4 degrees, to maintain a base temperature and save money at the same time.

For prolonged absences (weekends, vacations), a steeper drop to around 12-14°C is recommended. This temperature prevents pipes from freezing in winter, while greatly reducing consumption.

Blocking radiators with furniture

Placing bulky furniture, heavy curtains or drying clothes in front of the radiators prevents warm air from circulating properly. This obstruction reduces heating efficiency and forces the system to run longer to reach the desired temperature. Make sure there's at least 20 cm of free space in front of each radiator.

Neglecting heating system maintenance

A poorly maintained heating system can consume up to 12% more energy. The mandatory annual service for gas and oil-fired boilers is more than just an administrative formality. It's a necessity to guarantee the efficiency and safety of your installation. Regular cleaning of radiators, draining of water radiators and dust removal from electrical systems also improves performance.

Optimize thermal comfort without raising the temperature

There are many strategies for improving your feeling of warmth without touching the thermostat. These complementary methods make it possible to maintain recommended temperatures while guaranteeing optimum comfort.

Insulation: the most profitable investment

Before you try to heat more, make sure your home retains heat efficiently. A poorly insulated house can lose up to 30% of its heat through the roof, 25% through the walls, 20% through air exchange and leaks, 15% through windows and 10% through the floor. Insulation is therefore the most powerful lever for reducing your heating needs.

Attics and roofs should be the priority, as heat rises naturally. Wall insulation, whether internal or external, comes next. Replacing single-glazed windows with double- or triple-glazed units can reduce heat loss in this part of the home by 40%.

A wide range of financial assistance is available for this work: MaPrimeRénov', energy saving certificates (CEE), zero-rate eco-loans and local government grants. These schemes can cover up to 90% of the cost of work for low-income households.

Textiles and accessories to enhance comfort

Textiles play a major role in heat perception. A simple wool or fleece blanket can help you feel 2-3 degrees warmer. Thick carpets, especially on tiled or parquet floors, insulate against the cold coming from the ground and create a warmer atmosphere.

Invest in suitable indoor clothing: warm socks, lined slippers, wool or fleece sweaters. It may seem obvious, but many people stay lightly clothed at home and compensate by turning up the heat, which is counterproductive both economically and ecologically.

Thermal curtains are also an excellent investment. Closed at night, they create a layer of insulating air that reduces heat loss through windows by 25 to 30%. Open during the day, they let in free solar gain, which naturally warms your home.

Air humidity: an often overlooked factor

Relative humidity has a considerable influence on temperature perception. Air that's too dry, which is common in winter with heating, feels cold even when the temperature is right. Conversely, slightly humid air (between 40% and 60%) provides a more pleasant sensation of warmth.

A humidifier can significantly improve your comfort, especially with electric heating, which dries out the air. Simple methods also exist: drying laundry indoors, placing containers of water near radiators, or growing houseplants that release moisture through perspiration.

Technologies for intelligent temperature management

Connected thermostats and intelligent heating management systems have revolutionized our ability to optimize the temperature of our homes. These technologies offer precise, automated control that can generate substantial savings.

Programmable and connected thermostats

A programmable thermostat automatically adjusts the temperature to suit your lifestyle. You can program time slots: reduced temperature at night and when you're away from work, temperature raised before you wake up and return from work. This automation ensures that you never overheat your home unnecessarily.

Connected thermostats go further, learning your habits and adapting automatically. Some models use your smartphone's geolocation to detect when you are leaving or approaching your home, and adjust the heating accordingly. Others analyze weather forecasts to anticipate outdoor temperature variations.

The savings generated by these devices are real: between 15% and 25% reduction in consumption, according to ADEME. The initial investment, usually between 100 and 250 euros for a quality thermostat, pays for itself in 2-3 years for most households.

Thermostatic valves for precise zoning

Thermostatic valves installed on each radiator enable individual temperature control for each room. This solution is particularly well suited to homes with different thermal requirements. As a result, you can automatically maintain 19°C in the living room, 17°C in the bedrooms and 22°C in the bathroom.

Connected models go a step further, allowing you to control the system from your smartphone and program each room on a weekly basis. Some even incorporate presence sensors that switch off the heating in unoccupied rooms.

Advanced control systems

For central heating systems, modern control systems optimize boiler operation according to multiple parameters: outdoor temperature, indoor temperature, building thermal inertia, occupancy schedules. These controls can reduce consumption by a further 10-15% compared with a basic system.

Health and housing temperature: finding the right balance

The temperature of your home has a direct impact on your health and well-being. It's essential to find the right balance between saving energy and maintaining a healthy environment.

The risks of overheated housing

An overheated home has a number of health drawbacks. The air becomes too dry, irritating the airways and mucous membranes, promoting nosebleeds and aggravating asthma symptoms. Skin also becomes drier and may itch.

Excessive temperature, especially in bedrooms, disrupts sleep and can lead to headaches, chronic fatigue and reduced concentration. Studies show that a bedroom maintained above 20°C significantly increases the time it takes to fall asleep and reduces the duration of deep sleep.

A too-warm environment also encourages the proliferation of dust mites and molds under certain conditions, which can aggravate allergies and asthma.

The risks of a too-cold home

Conversely, an insufficiently heated home also poses problems. Below 16°C, health risks increase, particularly for vulnerable people: young children, the elderly, people with chronic illnesses.

Cold promotes respiratory illness, weakens the immune system and can trigger asthma attacks. It also increases blood pressure and cardiovascular risk in frail people.

Dwellings that are too cold and damp encourage the growth of mold, which is particularly problematic for respiratory health. Excessive humidity combined with cold creates an environment conducive to fungi and dust mites.

People with special needs

Some people require special attention when it comes to temperature:

The elderly have increased sensitivity to cold as their metabolism generates less body heat. A temperature of 20-21°C in living areas may be necessary for their comfort and health.

Babies and young children have immature thermoregulatory systems. Their room must be kept between 18 and 20°C, and it's crucial to monitor the temperature regularly with a room thermometer.

People with chronic illnesses (arthritis, asthma, cardiovascular disease) may require slightly higher temperatures to avoid aggravation of their symptoms.

Adapt the temperature to the season

Managing your home's temperature isn't limited to winter. Each season has its own specificities and requires adjustments.

Winter: the critical period

This is obviously the period when the question of heating is most crucial. Maintain recommended temperatures (19°C in living areas, 16-17°C in bedrooms) and make the most of free solar gain: open curtains and shutters during the day on sunny facades, and close them after dark to limit heat loss.

Air your home for 5-10 minutes a day, with windows wide open, even in winter. This rapid ventilation renews the air without cooling the walls, and prevents the accumulation of humidity and indoor pollutants. Remember to turn off the heating during ventilation.

Half-season: the art of timing

In spring and autumn, outside temperatures can vary greatly between day and night. Use your thermostat's programming to fine-tune your heating: turn it down or even off during the day when temperatures are mild, and turn it back up in the evening if necessary.

It's also the ideal time to perform pre-winter maintenance on your heating system, and to carry out minor insulation work to improve your thermal comfort.

Summer: limiting incoming heat

Although this guide focuses on heating, summer temperature management is a complementary topic. Close shutters and curtains during the day to block out the sun's heat, and ventilate generously at night and early in the morning when the outside air is cooler. Good thermal insulation works both ways: it keeps you warm in winter and cool in summer.

If your region experiences very hot summers, investing in external solar protection (shutters, blinds, pergolas) is more effective than air conditioning and much more economical in the long term.

Conclusion

Choosing the right temperature for your heating system is a decision that simultaneously influences your comfort, your health, your budget and your environmental impact. The ADEME recommendations - 19°C in living rooms, 16-17°C in bedrooms, 22°C in bathrooms when in use - represent an optimal balance validated by scientific studies.

Every degree counts: reducing the temperature by just one degree cuts your consumption by 7% and can save you several hundred euros a year. These savings become even more significant when combined with good insulation, efficient control equipment and adapted daily habits.

Modern technology, with connected thermostats and thermostatic valves, makes it much easier to optimize your heating management. These relatively modest investments pay for themselves quickly, while improving your comfort.

Don't forget that the temperature displayed on a thermostat is just a number: your actual comfort also depends on insulation, air humidity, the textiles you use and your clothing. Before you turn up the heat, explore these additional levers that improve your feeling of warmth without consuming more.

Finally, adapt these recommendations to your personal situation. Needs vary according to age, health, activity level and individual preferences. The important thing is to find your own balance between comfort, savings and respect for the environment.