CMV, controlled mechanical ventilation, has become mandatory in all new homes, allowing air quality to be optimized as much as possible. But different CMV models and technologies exist. So, how do you choose the right CMV according to the construction guidelines of your individual house? And how, once your house is built, to sustainably maintain your CMV. Maisons SIC, a specialist in house construction in the South West for over 50 years, gives you all the information you need to make your choice of VMC.
The different types of VMC
When building a new home, ventilation is a crucial element that should not be overlooked to ensure good indoor air quality.
Controlled Mechanical Ventilation (CMV) is an effective solution for renewing air and ensuring optimal circulation.
It exists three main types of VMC on the market : the self-regulating single-flow CMV, the hygroregulated CMV, and the double-flow CMV. Each of these technologies works differently and offers varying levels of comfort.
- Also read: Building a healthy house in the South West
The Self-Regulating Single Flow CMV
The self-regulating single-flow CMV is the most basic and most common ventilation system in new constructions. Its operating principle is based on a device that extracts stale air from damp rooms (such as kitchen, bathroom and toilet) and throws him out of the house.
Fresh air enters the house through air inlets generally located on the windows of the living rooms (bedrooms, living room). The air flow extracted by this type of VMC is constant and does not vary depending on the interior conditions of the house, such as humidity or temperature.
This automatic regulation allows maintain stable air quality, without requiring any intervention from the occupants. The VMC motor therefore operates at a constant speed, regardless of the occupancy of the premises or the weather.
The Single Flow Hygroregulated CMV
The hygroregulated CMV, also called hygroregulated single flow CMV, is a more advanced version of the self-regulated single flow CMV.
It works on the same principle of extracting stale air from damp rooms, but it has a special feature: it adapts the flow of extracted air according to the humidity present in the indoor air.
The system is equipped with hygroregulated extraction vents which automatically adjust their opening according to the humidity level detected. In practice, this means that when the humidity in the house increases, for example during a shower or cooking food, the hygroregulated CMV increases its air flow to extract more humid air. Conversely, when the humidity is low, the extraction flow rate decreases, which optimizes air renewal while reducing heat loss.
This type of VMC can be classified into two categories: VMC hygro A, which only adjusts the extraction vents, and VMC hygro B, which adjusts both the air inlets and the extraction vents for finer regulation.
The Double Flow CMV
The double flow CMV is a more sophisticated ventilation system which ensures both the extraction of stale air and the supply of fresh air.
Unlike single-flow CMV, double-flow CMV does not bring in air directly from outside through grilles located on the windows. Instead, fresh air is drawn in from outside via a network of ducts, then passes through a heat exchanger before being blown into the living areas.
The heat exchanger, which is the heart of this system, recovers the heat contained in the extracted air and transfers it to the incoming fresh air. This technology makes it possible to retain part of the heat in the indoor air while renewing the air efficiently. Thus, in winter, the incoming air is preheated by the extracted air, while in summer, the system can limit overheating by operating in reverse.
The double flow CMV is often equipped with filters which purify incoming air, reducing outdoor pollutants and allergens, while maintaining constant ventilation.
Each of these VMC solutions has operating specificities that meet different needs in terms of indoor air renewal. Understanding how each type of VMC works will allow you to make an informed choice when building your new home.
How to choose the right VMC for your needs?
Choosing a VMC (Controlled Mechanical Ventilation) system suited to your home is an essential step in ensuring optimal comfort and good indoor air quality.
Each type of VMC has its own specific characteristics and meets different needs depending on the type of housing, its insulation and your budget. Here are some tips for Maisons SIC to help you choose the VMC best suited to your needs.
Choose a VMC according to your budget and the configuration of your home
The choice of your VMC depends first and foremost on your budget.
La Self-adjusting single flow CMV is the most economical solution. Its purchase cost, generally between €300 and €750, and its ease of installation make it an ideal option for small budgets or for those looking for a basic solution. This system is particularly suitable for homes that do not require a high level of air quality control, such as single-family homes with limited air volumes or small businesses.
On the other hand, if you have a larger budget and your priority is to limit energy losses while improving indoor air quality, the VMC dual streams is an interesting option. With a price between €2 and €500, this system offers efficient heat recovery, ideal for well-insulated homes or homes renovated to modern energy standards. However, its installation is more complex and requires a dedicated space for the box and the air suction and insufflation ducts.
For an intermediate budget, the Humidity-controlled single flow CMV can be an excellent alternative. It costs between €500 and €1 and automatically adjusts its air flow according to the humidity level. This type of VMC is recommended for homes where it is important to maintain a good level of comfort while saving energy.
Adapt your VMC to the thermal characteristics and ventilation needs of your home
The characteristics of your home, particularly its level of thermal insulation, are also decisive for the choice of VMC.
La VMC dual streams is particularly suitable for new or renovated houses with excellent insulation and high-performance airtightness. By recovering the heat from the extracted air to heat the incoming air, it significantly reduces heating requirements. This system is ideal if you live in a cold region or if you are looking for optimize your energy consumption.
On the other hand, if your house does not have optimal insulation or if you do not want to carry out major work to install a double flow CMV, a Humidity-controlled single flow CMV may be a more practical solution. Thanks to its mechanism for adjusting the air flow according to humidity, it offers an interesting compromise between energy savings and comfort. It is also easier to integrate into existing buildings where the installation of additional ducts would be complex.
For homes that require simpler, more economical ventilation, the Self-adjusting single flow CMV remains a viable option. It is easy to install and maintain, although it does not allow for regulating airflows based on humidity or temperature. This system may be sufficient for sparsely occupied houses or limited-use spaces, such as outbuildings or small dwellings.
- Also read: Build a house without heating, or almost
Consider your comfort and air quality priorities
Your daily comfort and indoor air quality are also important criteria in choosing your VMC.
La VMC dual streams offers the best level of comfort thanks to its ability to filter pollens and outdoor pollutants, and to limit the sensations of cold drafts. It is particularly recommended if you have allergy problems or if you want to maintain optimal air quality throughout the year.
For a compromise between comfort and cost, the Humidity-controlled single flow CMV is an interesting alternative. It automatically adapts to humidity variations, thus ensuring optimal air renewal while avoiding significant energy losses. This system is suitable for homes where air quality is a concern without requiring the level of control offered by a dual-flow CMV.
Finally, for homes where the need for ventilation is less demanding, the Self-adjusting single flow CMV may be sufficient. It provides constant air renewal at a low cost, while requiring little maintenance. However, it can cause drafts and heat loss, making it less suitable for harsh climates or highly insulated homes.
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To best choose your VMC in your new house, contact Maisons SIC !