Green heating: it's possible?

François Chevalier

An ecological heating, it exists? A priori, difficult to reconcile maximum comfort for low energy consumption ... Discover our tips for heating your living rooms by finding the right compromise:

The French spend an average of 7% of their budget on energy expenses, about half of them on heating. To lower the bill, two ways. The first is to equip a fossil energy system (oil, gas) by choosing a recent equipment with improved performance. The second is to move towards renewable energies. Investment is more important, but the prospects for savings are not insignificant. The responsibility of fossil fuels for greenhouse gas emissions, their programmed drying up in the longer term, and therefore the increase in their cost, encourage us to do so. Among the renewable energies: the wood, the solar and the calories naturally contained in air and in water, captured by a heat pump. And electricity? It belongs to one or the other category according to its origin

Renewable energies still too expensive

So, what to choose? Everything is a matter of location, but also of budget. According to the latest Ifop study for Qualit'EnR, while 88% of French people consider their energy expenditure high and are attracted by renewable energies, they are not ready to equip themselves at any price. 39% think that the price of equipment is the first brake. Often, they find the depreciation period too long. As proof, another survey conducted by INSEE in 2010 shows that wealthy households have benefited more than others from technical progress. Among the most popular renewable energies in the main residences, the wood insert takes the lead with 18%, followed by the wood stove (11%), then the heat pump (8%). Far behind, we find, equal, the solar water heater, the combined solar system (heating / hot water) and the wood boiler (3%). This is little…

Isolate to lower the bill

Whatever your choice, the first thing to understand is that the cheapest energy is the one you will not use. For this, only one way: isolate. Not doing it is throwing money out the window. First, by having to invest in more powerful hardware. Indeed, a dwelling of 100 m2 not insulated will require a boiler of 13.5 kW against 8.75 kW for a perfectly insulated house (these powers are out of domestic hot water). Then, consuming a lot more to compensate for the loss of calories due to thermal bridges and other faults in the house envelope.

After the insulation, comes the ventilation. Essential for renewing the air and eliminating moisture, a source of multiple inconveniences (peeling off wallpaper, mushrooming, etc., see page 92). Inevitable finally, the regulation of heating systems. It is done centrally by a room thermostat acting on the activity of the boiler or on each radiator. Centralization, appropriate in a single-storey home, can be moderately effective in a multilevel home, especially if the insulation is not perfect. In the latter case, thermostatic valves on each heat transmitter, if possible programmable, are preferable.


More economical and less polluting, the oil option: is it still a solution for the future? Yes and no. Yes, as the materials exploiting this resource have made (and still make) enormous progress in terms of performance and environmental preservation. No, because eventually oil will run out, we will have to abandon this option, just as most coal-fired boilers were eliminated in the 1960s. But the life of a well-maintained machine is twenty years, this choice is still playable for at least a generation.

Advantages: good performance of new boilers to heat large volumes, tax reduction on high performance models. Disadvantages: fossil energy, storage required, odor, high price indexed on that of oil, pollution. Our advice: be careful not to under - or oversize the equipment, your boiler would not work at the right rate, resulting in increased consumption. Remember to equip your radiators with thermostatic faucets to regulate the temperature in each room.

The choice of gas: city gas remains very popular, despite the constant increase in prices. To his credit, no storage, cleanliness and excellent yields of recent models of boilers, condensing or low temperature in particular. His future ? Less threatened than fuel oil because the reserves seem more important. As for alternative solutions (controversial shale gas or biogas produced from our waste), they are far from being operational. Advantages: no storage (except propane), fast heating, clean, tax reduction on efficient boilers. Disadvantages: fossil energy, constantly increasing price, pollution. Our advice: have a thermal balance of your home to choose the good power. A low temperature model associated with a heated floor offers good results and comfort.