We have entered the cold season with both feet… Despite soaring prices and calls for sobriety, woolen sweaters and down jackets have their limits. Obviously, the radiators are involved. And in 40% of French homes, this means turning up the gas boiler, we remind you. France gas. “12.5 million main residences have this method of heating, not nothing out of 65 million inhabitants”, supports Madeleine Lafon, general delegate of the professional union in the sector.
Can we imagine a France without a gas boiler? This is the direction the government is pushing. Since last year, they have been banned in new homes. At the beginning of the summer, the government considered completely banning all new installations, including old ones, from 2026. Before backing down a few months later, “so as not to leave our compatriots, particularly in the most rural areas, without solution”, justified Emmanuel Macron, at the end of September, in his speech on ecological planning.
The war in Ukraine as a boost?
Instead, the executive gradually excludes gas boilers, energy renovation aid systems. A drastic shift when the purchase of a gas boiler was strongly supported some time ago. The war in Ukraine and the fear of running out of gas last winter “necessarily had an accelerating effect, pushing France, and more broadly the European Union, to reduce their consumption of natural gas as quickly as possible”, begins Isabelle Gasquet, “energy efficiency” project manager at Cler – network for the energy transition.
“But the need to reduce greenhouse gas emissions in buildings was already pushing us in this direction. Whatever happens, we will eventually have to do without natural gas and other fossil fuels. [le fioul notamment] in our heating methods. »
Heat pumps, solution n°1?
The question is therefore more that of how. In other words: What are we replacing gas boilers with? By heat pumps (PAC)? It is the main alternative in building decarbonization scenarios. “HPs do not create heat or generate combustion, unlike gas. They only transfer calories into the external environment, into the ground or into the air, towards the interior of your house, explains Arnaud Kautzmann, secretary of the French Association for Heat Pumps (Afpac). This is their whole advantage: high energy efficiency with a low carbon footprint.” But are they really effective in extreme cold? ? It’s a recurring fear. “The country with the most heat pumps in Europe is Sweden, whose winters are much harsher than ours,” Arnaud Kautzmann reassures.
All the same, heat pumps need electricity. And the colder it is, the more they consume. Not negligible in the budget? “It depends on what we are comparing,” replies Arnaud Kautzmann. A household that swaps its electric heating for a heat pump will divide its energy consumption by three, and therefore its heating bill. On the other hand, between a high-performance gas boiler and a heat pump, we are on approximately the same order of energy consumed. It all depends on how gas and electricity prices evolve. »
The boom in heat pumps to the detriment of the balance of our electricity system?
But bills aren’t the only issue. Madeleine Lafon invites us to have a more macro vision of the situation: “The energy transition requires electrification of our uses, and therefore an increase in our electricity production,” she recalls. The advent of the electric car is already a major challenge. Do we add the electrification of our heating methods? » In his prospective study on the evolution of the electricity system published in September, RTE wanted to be reassuring. The electricity network manager estimates the massive deployment of heat pumps to be absorbable by the electricity system and is counting on 11.5 million heat pumps installed by 2035. Ten times more than today.
At France Gaz, we still invite you not to give up on the hybrid boilers, which combine gas boiler and heat pump, with the promise of getting the most out of these two energies. “Typically during peaks in electricity consumption in winter, these boilers can switch to gas to relieve the network,” illustrates Madeleine Lafon, who does not despair that the government will reinstate aid for this technology. Especially since “the gas that we will inject into the network will increasingly be renewable gas, and even 100% by 2050”, aims France gaz.
Isolate first and foremost?
Should we use this green gas to heat our homes?, asks Arnaud Kautzmann, who sees other priorities. “Particularly in mobility and industry, where certain uses will be very complex to electrify,” he believes. But you should not believe that the heat pump has the answer to everything. “Existing PAC technologies lend themselves quite poorly, in certain cases, to the renovation of collective housing,” concedes the Afpac secretary. Particularly due to lack of space. » Added to this is the barrier of their price, much higher than gas boilers (read box). Arnaud Kautzmann does not see them falling in the short term. These PACs are already highly subsidized in addition.
“PACs are a major solution, but not the only one,” recalls Isabelle Gasquet. You have to do it on a case by case basis, each accommodation, each building is different. » “Typically, in a region where wood resources are abundant, a household may have every interest in turning to a biomass boiler », she illustrates. But before changing the heating system, Cler calls “to start by insulating your home”. “This is the best way to avoid investing in an oversized device and therefore too expensive compared to your real needs,” explains Isabelle Gasquet. But also, on a national scale, to reduce our energy consumption as much as possible, the best way to facilitate the energy transition. » In September, RTE also made increasing the volume and efficiency of thermal renovations in buildings an imperative. And set the target of 380,000 homes renovated per year in 2035. We were at 90,000 in 2022.
Geothermal, air/air or air/water… How do heat pumps work?
“There are three main types of heat pump technologies on the market,” summarizes Arnaud Kautzmann. There is the geothermal heat pump, which collects energy from the ground, and these calories heat a water circuit which passes throughout the house. This solution lends itself better to new homes since it is necessary from the outset to provide a place outside the house to install the sensors which will recover the heat in the ground. »
Added to this are air/water and air/air heat pumps. They have one thing in common: seeking external energy. “For the first technology, the most widespread and the one that best lends itself to replacing a gas boiler, this hot air once again heats a water circuit which then passes throughout the house,” continues Arnaud Kautzmann. For air/air heat pumps, hot air taken from outside is blown directly into the house. »
That’s it for the three technologies. And the price ? If we take air/water heat pumps, the most widespread technology to date, we have an average price of 13,000 euros (with domestic hot water), indicates Hellowatt. A gas condensing boiler costs from 1,500 to 5,000 euros, estimates the same comparator.