Electric auxiliary heater: thermal performance at the heart of every room

The electric auxiliary heater allows you to quickly warm up a room when the main heating is insufficient or when you want to avoid heating the entire home. In mid-season, during cool evenings or temporary temperature drops, it provides a welcome heat boost in an office, bedroom, or living room. 

Our range of radiators, as well as Thomson heating solutions, offer models designed to combine ease of use, thermal efficiency, and energy consumption control.

Which auxiliary heater to choose for optimal comfort?

Each technology meets a different need depending on the room to be heated and the desired duration of use. The choice therefore mainly depends on your usage: the need for immediate heating for a few minutes or the desire for a comfortable temperature over several hours.

Dry inertia auxiliary heating: the economical choice

The dry inertia auxiliary heater is one of the most interesting solutions for regular use. Its heating core, made from materials such as ceramic or cast iron depending on the model, stores the heat produced by the resistance before gradually releasing it into the room. A ceramic heater offers a responsive temperature rise, while a cast iron heater favors long-lasting heat release. The gradual diffusion thus limits temperature fluctuations and reduces frequent reheating.

Conversely, the fan heater prioritizes a very rapid temperature rise thanks to the immediate diffusion of warm air. It remains particularly suitable for occasional needs, for example to heat a bathroom before a shower or quickly warm up a workspace. However, once turned off, it does not retain heat and must operate continuously to maintain the desired temperature.

Dry inertia radiators are therefore particularly suited for users looking for economical heating for regular use. To benefit from both quick heating and even heat distribution, the double-core heating radiator combines a responsive heating film with an inertia core capable of prolonging heat release.

Fluid inertia supplementary radiator (oil-filled)

The fluid inertia supplementary radiator, also called an oil-filled radiator, is based on a simple principle: an electric resistance heats a heat transfer fluid contained inside the device. This liquid stores the heat and then gradually releases it through the radiator’s walls, allowing a steady heat output in the room.

Thanks to this high thermal inertia, the oil-filled radiator continues to emit heat even after the resistance is turned off. The temperature thus remains more stable than with a fan heater, while limiting heat fluctuations. It is especially suitable for rooms occupied for several hours in a row, such as a living room, bedroom, or office.

On the downside, its heating up is slower than that of a fan heater or a double-core heating device. Its size is also bulkier and its weight heavier due to the presence of the heat transfer fluid.

How to calculate the power of your supplementary electric radiator?

A radiator suited to the room size heats more efficiently and prevents overconsumption.

As a general rule, you should plan for about 100 Watts per m² in a properly insulated home. These estimates are given as a guideline and may vary depending on the insulation of the dwelling.

Low energy heating solutions and economical electric radiators then allow you to optimize this power through better heat management.

Maximize your savings with presence and open window detectors

Supplementary heaters, whether portable or fixed, now include smart features to better adapt their operation to household needs. When paired with a connected electric heater or smart electric heaters, they offer precise temperature control to the degree, automatic shutdown in case of absence or open window, and remote control via a mobile app.

A heater with an open window detector detects a sudden temperature drop caused by ventilation and automatically reduces its Wattage to avoid unnecessary consumption. Models equipped with a presence detector adjust heating according to the actual occupancy of the room. These features allow for more autonomous, comfortable, and better-controlled heating on a daily basis.

Use, safety, and ambient air management

For safe use, the heater must be placed on a stable and clear surface, leaving enough space around the device to ensure good air circulation.

Modern models generally feature multiple protections:

• overheat safety;
• tip-over safety for portable devices;
• precision electronic thermostat;
• automatic shutdown in case of anomaly.

For damp rooms, electric towel warmers are a perfectly suitable solution.

The feeling of warmth also depends on the quality of the ambient air. An appropriate humidity level improves comfort and limits problems related to overly humid air. In addition to heating, an air dehumidifier helps maintain an optimal humidity level throughout the year.

FAQ

What is the most economical type of supplementary heater?

For regular use, dry inertia and oil-filled heaters are more economical than fan heaters. They retain heat and limit electricity consumption.

Fan heaters heat up very quickly but must run continuously to maintain temperature, making them more energy-consuming. For frequent use, dry inertia is usually preferred. Oil-filled heaters remain an interesting alternative when looking for gentle heat over several hours.

What power should you choose for an electric supplementary heater?

You generally need about 100 Watts per m² in a properly insulated room.

Sizing also depends on insulation, ceiling height, and room usage. Choosing the right power ensures quick heating without excessive consumption.

Can a supplementary heater be used continuously throughout the winter?

Yes, a high-end supplementary heater can be used regularly, but it is primarily designed to temporarily improve the thermal comfort of a room. 

To heat an entire home daily, a fixed heating system is generally more suitable than a supplementary device. However, recent models equipped with an intelligent electronic thermostat, personalized programming, and presence sensors allow frequent use while controlling consumption.

To optimize air circulation and better distribute heat in your home, also discover our guide to installing a ceiling fan.