When should the heating be turned on?

With the gradual arrival of cooler temperatures, the question of the ideal time to turn on the heating comes to the forefront. Finding the balance between thermal comfort and managing energy expenses is an important issue. Often, households hesitate to turn on the heating for fear of seeing their bills explode, while others prefer to anticipate in order not to suffer from the cold. This question depends on several factors: the outside temperature, the insulation of the home, the type of heating, and of course, the consumption habits and sensitivity to cold of the occupants. Combining technical know-how and pragmatic advice, this article breaks down the key criteria and tips for determining when to turn on the heating, in relation to current realities and updated data from 2025.

When to start heating? Defining the appropriate heating threshold temperature

The main criterion for knowing when to start heating is based on the indoor temperature felt and consistently observed. Experts generally recommend taking action from the moment the ambient temperature is continually below 19°C. This value represents a compromise between comfort and energy savings. Indeed, according to the Agency for Ecological Transition (Ademe), maintaining a living room around 19°C ensures a warm atmosphere without overconsumption.

The outside temperature also plays a determining role. For example, when outdoor temperatures durably drop below 14°C for several days, it is often wise to turn on your heating system. The threshold may vary by region: in some colder areas, activation can occur earlier, while in temperate or well-insulated regions, it can be delayed.

These recommendations are also supported by field observations. Simon King, a weather specialist, points to the figure of 15°C as the outdoor temperature at which residents often start to gradually turn on the heating. This parameter is useful for anticipating the start of the heating season and thus optimizing the heating adjustment to avoid running it unnecessarily.

To refine this advice, here is a list of the main threshold temperatures often retained:

• 19°C: minimum indoor temperature to maintain for general thermal comfort (Ademe).

• 18°C: temperature recommended by the World Health Organization for healthy individuals.

• 20°C: recommended for children, elderly or fragile individuals.

• 14-15°C: outdoor temperature to monitor to consider starting the heating.

Ultimately, the timing for turning on the heating should also take into account individual thermal sensitivity and the health status of the occupants. To avoid unnecessary expenses, it is advisable to favor gradual and regular adjustments rather than abrupt and total activations at the first chills.

Impact of regional habits on the time to turn on heating

Climatic and cultural differences strongly influence the choice of when to turn on the heating. Topography, latitude, and local humidity modify thermal perceptions. For example, the northwestern regions of France are generally cooler and more humid, which may justify an earlier start of heating compared to the south or east.

Other factors come into play, such as the insulation of homes. In well-insulated buildings, maintaining a pleasant temperature is possible for longer without intense heating, while older houses with insufficient insulation often require earlier activation and stronger regulation. Lifestyle also plays a role: remote work, permanent presence at home or prolonged absence impact heating settings.

To frame these variations, several regional data sources can be consulted and adjusted to optimize heating. Aquatherm37, for instance, offers detailed advice on when to turn on heating according to your region. Selectra includes in its study the average recommended date to start the heating season by geographical zone, to discover here.

The meteorological history of previous years serves as a valuable barometer to anticipate winter and not turn on the heating too early. However, heating for longer or at too high a temperature ruins the energy savings that are intuitively sought.

Below, a table summarizes the indicative periods to start heating by major climatic zones in metropolitan France:

• Regularly consult local weather forecasts.

• Take into account the relative humidity which reinforces the sensation of cold.

• Adjust heating settings based on the occupancy and usage of rooms.

• Remember to maintain the system before the cold season to optimize efficiency.

Additional sources and expertise on the subject:

• Primagaz - When to turn on the heating

• DV Maintenance Heating - Practical advice

• Expertise Energy - Guide and practical advice

Turn on heating in winter: tips to optimize heating and energy savings

Turning on the heating marks the entry into the cold season but can result in a significant increase in energy consumption. Optimizing this moment is crucial to limit costs while maintaining optimal thermal comfort. Several tips should be considered.

First, adopting a precise setting for the indoor temperature prevents waste. A temperature set between 18°C and 21°C meets most expectations. Higher, and the bill climbs rapidly. Using a programmable thermostat allows heating rooms when necessary, for example, only during occupancy periods.

Second, it is advisable to anticipate the start of heating by monitoring outdoor temperatures over several days and correlating with humidity levels. This prevents continually restarting appliances, which is energy-intensive.

• Install smart thermostats to automate heating based on the household’s habits.

• Favor a gradual temperature increase rather than a sudden heating, to preserve both the environment and the equipment.

• Regularly maintain equipment (boilers, radiators, valves) to ensure their performance.

• Insulate doors and windows to limit heat loss.

• Use complementary solutions like blankets, warm clothing, and space heaters to delay activation.

The law and certain financial aids in 2025 encourage these best practices. Eco-renovation, for example, allows for obtaining subsidies through the Coup de Pouce Heating program to upgrade installations to more efficient and less energy-consuming systems.

Beginning heating season: preparing and maintaining your installation for optimal ignition

Beyond the question of the timing for turning on heating, activation must be preceded by a maintenance and preparation phase essential to ensure safety and performance. Paul Leclerc emphasizes the importance of checking the condition of installations before the first annual startup.

The main recommended steps are:

1. Annual boiler inspection by a professional. This includes checking the burner, adjustments, and circuit tightness.

2. Cleaning and bleeding radiators to eliminate air contained in the circuit and ensure uniform heat.

3. Checking thermostatic valves for precise temperature settings.

4. Evaluating the insulation of pipes, often overlooked, to avoid heat loss.

An energy audit can also be considered to improve the system, particularly by integrating options such as home automation and geothermal heating, which innovative developments are greatly advancing in 2025. Initiatives such as those proposed by Dig Energy Geothermal Heating testify to this evolution towards sustainable and economical sources.

Regular maintenance prolongs the lifespan of equipment, avoids breakdowns during the cold season, and contributes to substantial savings by reducing unnecessary consumption due to malfunctions or performance degradation.

Thermal comfort and savings: tips for effective heating adjustment in 2025

Controlling heating in winter is a balance between ensuring sufficient thermal comfort and limiting energy bills. The heating adjustment should be gradual, adapted to the layout of the home, and consistent with new standards and technological innovations.

Modern solutions now incorporate connected thermostats capable of automatically adjusting according to occupancy, outside temperature, or even electricity pricing peaks. This type of regulation ensures optimized heat distribution and prevents unnecessary expenses, particularly in households where habits change frequently.

In parallel, it is recommended to:

• Properly insulate your house, for example by reinforcing double-glazed windows and doors.

• Turn off heating in unused rooms to reserve energy for living spaces.

• Practice quick and effective ventilation rather than lengthy, to limit heat losses.

• Use complementary accessories such as thermal curtains or thick rugs to retain heat.

Financial aids are still available to encourage energy renovation and the installation of efficient equipment. An overview of the programs and projects underway is accessible on the Coup de Pouce Heating platform.