Double flow ventilation: functioning pros cons installation costs

The Controlled mechanical ventilation (VMC) double flow is a ventilation system created to improve the quality of ambient air in the home and, in addition, to save energy. Its principle is simple since this device evacuates stale and humid air from the interior to the exterior, and breathes new, healthier air into the home from the exterior. Let’s see how the double flow VMC works more precisely, if it really keeps its promiseswhat are its strengths and weaknesses and what budget should be devoted to its installation.

Composition of a double flow VMC

A double flow VMC is composed of:

  • From an air inlet,
  • From an air outlet,
  • Of two duct networks :
    • One through which stale air is expelled from the dwelling,
    • The other through which fresh air enters the house.
  • of a electric fan for each duct network,
  • of a heat exchanger arranged under the roof of the dwelling and which allows:
    • To recover the heat contained in the stale air before its expulsion,
    • To breathe this heat into the new air coming from outside so that it arrives in the living rooms once warmed up.

It should be noted that the installation of a double flow VMC implies the connection of the heat exchanger to the waste water evacuation system, which allows the rejection of the water vapor that it generates.

Operation of a double flow VMC

The operation of a double flow CMV is not very complex unlike its installation.

Dual-flow Controlled Mechanical Ventilation is a ventilation device suitable for living. She has several roles: filter the air in order to guarantee a healthy atmosphere for the occupants of a house, improve thermal comfort while reducing the cost in terms of energy because it is supposed to participate in the reduction of heat losses. The double flow VMC has in fact been designed to heat the air coming from outside in order to limit the cold drafts which can corrupt the comfort of the habitat.

stale air is therefore extract from parts with water point (the kitchen, the bathroom, the shower room, the toilets, possibly the back kitchen) and looks new is breathed into the main parts (bedrooms, office, dining room, living room, etc.). The system is therefore designed so that stale air cannot mix with fresh air at any time.

It’s necessary choose a double flow VMC depending on his house. If his air flow is too important in relation to the volume of the dwelling, it will produce a air trop sec, which is not desirable for the comfort of the inhabitants nor especially for their health. Indeed, if the ambient air does not contain a minimum of humidity, it risks causing itchy eyes, dry skin, irritation of the throat and irritation of the sinuses. It is therefore strongly recommended to seek advice from a professional to choose the double flow CMV model perfectly suited to your home.

Double flow VMC: advantages

The double flow VMC presents significant advantagessuch as :

  • L’improvement of the ambient air inside the house,
  • Allows reduce excess humidity within the dwelling, which is important for the health of the occupants of the dwelling, because we know that too much humidity generates molds responsible for allergies and which, in addition, deteriorate materials, furniture, etc.
  • L’heating economy,
  • The good incoming air quality since once this new air is filtered, it is rid of bacteria, pollen, fine particles, mold and spores, which is a real plus in terms of health,
  • No more need to install aerators on the windows, which at the same time reduces the perception of noise from the outside,
  • Compatible with Provençal wells, Canadian wells, heat pumps, etc. for better thermal regulation. Even cools the indoor air in summer, which avoid to invest in a air conditioner quite expensive, energy-intensive and controversial for its health effects.

Double flow VMC: disadvantages

It has drawbacks that may discourage some homeowners.

  • Not easy to install in an old house since the duct networks were not provided for in the plans,
  • Can only be installed in a home that has a good insulation to be efficient: wanting to install a double flow VMC therefore implies renovating your house and redoing all the insulation, which requires an imposing budget,
  • Can be placed in the old when it is renovated, but its pipes may occupy a place enough consequent,
  • The system must be installed in a heated room,
  • There are condensation risks in the ducts, which generates mold in the home in the medium term, in the event of:
    • Non-compliant installation (this is why it must always be entrusted to a professional),
    • Extended system shutdown.
  • Involves having a sufficient space because his clutter is not negligible, which can be a problem for new home buyers who have a tight budget forcing them to opt for a small house without any adjoining rooms,
  • All air vents should be carefully dusted as often as possible,
  • Of the noises are perceived by the occupants of the living rooms at the level of the air outlets,
  • The condition of the ducts requires a very regular control,
  • The complete cleaning of the ducts must be done every 9 or 10 years,
  • The exchanger filters should be checked frequently and their replacement must be completed each semester. At the slightest oversight, the engines end up run at full speed :
    • generating encore more noise pollution than usual,
    • resulting in a increased energy bill.
  • The profitability is not obvious, quite the contrary since it appears that the double flow VMC is energy-intensive,
  • Hard to reach the requirements imposed by thermal regulations.

In view of all its drawbacks, Double Flow Controlled Mechanical Ventilation does not seem to keep all its promises.

VMC double flow: what budget for the installation?

It is necessary to count between €2,000 and €3,600 pour have a double flow VMC installed at home. No need to take care of it yourself because the installation of this device is extremely complex. It requires extensive experience in the field. This is why it is necessary contact a pro whose skills are real. Do not hesitate to request multiple quotes from a few local pros, making sure to select each RGE certified craftsmanwhich means Recognized Guarantor of the Environment.

A new generation of double flow VMC presents much less disadvantages than that which we have just presented. It’s here VMC double flux thermodynamics coupled with a heat pump, but it can only be installed in regions where the climatic conditions are particularly favorable, and exclusively in passive houses. This device can still be of interest to a good number of owners. It is usually a reversible system which can therefore, in addition to being a state-of-the-art VMC, serve as an air conditioner. This thermodynamic double flow CMV requires, depending on its power, a substantial budget ranging from 8,000 to 16,000 €, but for such an amount the price of the installation is included.

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