Faced with climate change, making your home more ecological is possible

Housing is, for households, one of the areas that emits the most CO2. However, it is possible to make your house or apartment greener. The slopes of Alec de Montpellier.

At a time when climate change is cruelly obvious, many people are seeking to reduce their ecological footprint. However, for households, it is housing that weighs the most CO2, behind transport: 46 million tonnes per year in France according to a government report.

Should we then make our home more virtuous ? "There are many avenues to develop on questions of mastery of energy", responds Nicolas Cattin, head of the Private Housing division, within the Local Energy and Climate Agency (Alec) of Montpellier, free advice service on saving water, water and energy. rsquo;energy and energy renovation. He adds that this work, an often decisive argument, can represent "a reduction in energy consumption of up to 30 to 50 %". And that in collective housing, even if they are more difficult to launch, studies by notaries have demonstrated that improving the green value of an apartment in the old one, confirmed by a better energy label, "allows you to obtain a price 10 to 15 % higher in the event of a sale", he relays.

First, insulation

This can be another source of motivation. But where to start ? "The priority is to first reduce housing needs", continues our expert. In other words, the key to the energy performance of your home remains insulation. "Because if we operate in reverse, we will design a new heating system as needed before insulation. We will pay more and we will consume more. It’is a loser on every point".

Nicolas Cattin, head of the private housing division within Alec de Montpellier Métropole. Midi Libre – MICHAEL ESDOURRUBAILH

Any renovation project therefore begins with the building envelope. For walls, assures Nicolas Cattin, the most efficient method remains "exterior thermal insulation (ITE) of facades, because it limits thermal bridges& quot;. Preferred. "There is less loss in winter and, in summer, even when the sun is beating down, heat is returned to the environment. The amplitude is 5° at 10 °C maximum. We therefore rely less on heating or air conditioning", he assures. Constraint on the other hand, the method is more expensive: between 130 euros; at 150 € by m² isolated, compared to 50 to 80 € from the inside. And if a facade renovation has been carried out recently, this would involve redoing everything. "In this case, we insulate from the inside, which allows the passage to review the electrical network since’we add a thickness of wall… but we lose a little surface area".

With this option, you must also choose the type of insulation. There are several, the most ecological being "cork and wood fiber" among the biosourced materials. Mineral wools are the most used due to their good quality-price ratio. "Each type of insulation has its advantages and disadvantages. It also depends a lot on the walls to be treated", intervenes Lukas Maurin, another specialist at Alec.

Roofing, carpentry and VMC

It is therefore necessary to be well advised… as for insulating your roof, since the technique (blowing, spreading, sarking, by panels or rolls), like the choice of insulation, can differ depending on the configuration of the roof and its condition. In all cases, the roof may be responsible for "approximately 30% of heat losses", the operation cannot than be beneficial.

Lukas Maurin, specialist in individual housing at Alec. Midi Libre – MICHAEL ESDOURRUBAILH

Obviously, we must not forget the joinery which can also cause a lot of energy loss, between 15 and 40%. "Classic double glazing is enough", assures Nicolas Cattin. Knowing that the bill can amount to 400 euros; to 1 200 € by window, you might as well be content with it. And since we're talking about windows, we can do without the habit of opening them for fifteen minutes a day, "which will bring in the cold in winter and heat in summer", by installing single-flow controlled mechanical ventilation (VMC). "It’s an interesting investment, between 1000 and 1500 € and advised in a global renovation project; this is not what will not seal the final envelope. Which, if we have to carry out all this work, can reach "more than 20 000 €", account Lukas Maurin.

Biomass, heat pump, solar…

It is once these operations have been carried out that the Alec experts propose to focus on the heating system. Fuel oil, "we separate it". Gas, if it’s recent and efficient, "we can keep". Among all sustainable heating sources, biomass, that is to say from wood, is the one that releases the least energy over its entire life cycle. Air-air heat pumps are very often recommended for their performance, flexibility and… the possibility of making it air conditioning in the summer. "Even if it’s considered overconsumption". Solar power is more recommended for heating water.

Small gestures too

Renovating is not enough to buy an ecological daily life. You also need to change your habits and favor eco-friendly actions to consume less water and electricity. Tools, "like aerators to place on faucets or energy-saving shower heads", for example, make this work easier. It is easy to change the bulbs to LEDs and opt for more economical household appliances. In the garden, "we favor Mediterranean plants that use less water" and, if we can, we cultivate our vegetable garden, the shortest circuit that exists. So many small gestures that already make it possible to be more ecologically virtuous, even without carrying out major work.

Alec de Montpellier regularly makes tools available to residents of the Metropolis to measure and manage their water and electricity consumption. Midi Libre – SYLVIE CAMBON

MaPrimeRenov' and other devices

Faced with the obstacle that the cost of energy renovation work can represent, numerous financial aids are available, some cumulative, others not, often subject to the reference tax income. "To be eligible, you must also have quotes and work carried out by certified companies Recognized Guarantor of the ;Environment (RGE)", adds Nicolas Catin, from Alec.

The best-known aid is MaPrimeRenov, a system which made it possible to subsidize, & On a national scale, the renovation of more than 620,000 homes in 2023, representing a cost of 3 billion euros. Since its creation in 2020, 2 million households have been affected. renovated, "éthus avoiding the emission of 5.3 tonnes of CO2", according to the National Housing Agency (Anah). Pretty figures which however hide help that is difficult to read or too restrictive à get. So, while the rules have been changed, reviewed on January 1, 2024 for an envelope of 5 billion euros, the government reviews its copy on May 15 (by simplifying it) face à a significant drop in construction sites (-43%) in the 1st quarter. While aid for insulation work was now conditional on the installation of new heating equipment, the ex’ecutive reverts to a grant for a single gesture of energy renovation. Among other changes. Complex. And face &agrav; explore the jungle of all available aid (zero-rate eco-loan, heating boost, local aid) and find those suited to your needs. its needs, it is advised… to get advice. The Occitanie Region, on its website Renovoccitanie.laregion.fr, allows for example to find the counter closest to your home to receive help. in the procedures and benefit from help which can prove to be substantial.

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