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What is double-flow CMV?

What is double-flow CMV?

We are talking more and more about double-flow VMC. But what exactly is this type of ventilation? Pascale Laire, head of Ventilation Group at Atlantic, tells us everything you need to know.

Why should we ventilate our accommodation?

In a home, the air is polluted by human activity but also by the fumes of cleaning products, glues contained in furniture etc. It is therefore important to ventilate to get the stale air out. The house is generally ventilated with controlled mechanical ventilation or VMC. Concretely, the air in humid rooms (bathroom, kitchen, WC) is sucked in through vents and then discharged outside while fresh air enters dry rooms (living room, bedrooms) via small air inlets. located above the windows. This creates a natural sweep of the air in the house or apartment.

What more does the double-flow CMV bring?

The double-flow CMV is an improved system of single CMV. In summary, it preheats the incoming air and filters it. But for the double-flow CMV to be effective, the house must be well insulated.

How does a double-flow CMV work?

The exhaust air extracted from humid rooms is generally at 20 ° when it is discharged outside. The double-flow VMC collects these lost calories and uses them to preheat the ambient air. Indeed, the outside air arrives in the housing by a pipe and crosses the hot stale air in an exchanger. The hot air transfers its calories to the fresh air which is then blown into the living rooms. Depending on the performance of the double-flow CMV, between 60 and 92% of calories are recovered. In addition, a filter blows fresh, unpolluted air, which is ideal for people who are fragile or allergic, in particular.

Can you give us an example to illustrate the recovery of calories by a double-flow CMV?

Imagine it is 0 ° outside and you want a temperature of 20 ° in the house. If your double-flow VMC offers a maximum efficiency of 92%, the incoming fresh air will be preheated to 18 °. You will just have to heat your accommodation a little bit to reach 20 °. Overall, the double-flow CMV saves 20% in heating.

What are the installation requirements for a double-flow CMV?

To be effective, the installation must be well done, by a professional. The CMV must be accessible in order to be able to ensure regular maintenance and servicing. It must also be avoided to install it in an unheated space and the pipes must be well insulated. There are already insulated conduits. Otherwise, rectangular pipes can be used in the false ceiling.

Concretely, what are the benefits of a double-flow CMV?

First of all, it saves on heating costs. It filters the air. It also removes the air inlets above the windows which allow outside noise to enter. In addition, some double-flow VMCs are equipped with a "bypass", which cools the incoming air in summer. The system starts automatically with temperature sensors.

Who installs double-flow CMVs?

It can be an electrician or a plumber, or an installer specializing in new energies. The manufacturers of VMC Double-flux can also indicate approved installers for their brand.

How do you maintain your double-flow CMV?

Every 4 or 6 months, the filters should be cleaned. And they must be changed at least once a year. The air vents in dry rooms should also be cleaned about once a year to prevent them from blackening.

What is the price of a double-flow CMV?

For a system supplied, it takes between 3,000 and 5,000 €. It all depends on the complexity of the accommodation. Installation in a two-story house under renovation costs more than a new one-storey house.

Are there tax incentives?

The double-flow CMV enters the framework of the zero rate eco-loan (Eco PTZ) only if it is coupled with heating improvement works. For the moment, she is not eligible for the tax credit. But a new generation of double-flow CMVs with "NF double-flow" certified performance should arrive by summer 2010. It is possible that then, the public authorities will agree to allow these new devices to benefit from the tax credit .

What are the future developments in terms of dual-flow CMV?

At Atlantic, for example, we will be releasing a new device in June 2010 that will display its performance: outside air temperature, temperature of the preheated air blown into the rooms, calories saved in heating. There will also be an "absence" function which will allow ventilation to be reduced when the inhabitants are away for several days.