Ventilation: healthy air in a well-insulated home
The better a home is insulated and airtight, the more important good ventilation becomes. It removes moisture, odours and CO2 and brings in fresh air. There are four systems, labelled A, B, C and D.
- System C and demand control
- System D with heat recovery
- Installation and maintenance
The four systems side by side
Every system does the same job: bring fresh air into the dry rooms (living room, bedrooms, study) and extract stale air from the wet rooms (kitchen, bathroom, toilet, utility room). The difference is how: naturally, or with a fan.
System A. Natural supply through vents in windows or walls, natural extraction through vertical ducts. No fans, but it depends on wind and temperature.
System B. Mechanical supply with a fan, natural extraction. Rare in homes.
System C. Natural supply through window vents in the dry rooms, mechanical extraction from kitchen, bathroom, toilet and utility room. Demand-controlled with sensors is more economical.
System D. Mechanical supply and extraction, usually with heat recovery: outgoing air warms the incoming fresh air. Needs an airtight home, ducts and filter maintenance.
Which system should you choose?
| System | Supply | Extraction | Good to know |
|---|---|---|---|
| A | Natural | Natural | No power use, but hard to control and weather-dependent. |
| B | Mechanical | Natural | Rarely used in homes. |
| C | Natural | Mechanical | Easy to install, also in renovations. Demand control with sensors limits heat loss. |
| D | Mechanical | Mechanical | With heat recovery the most efficient and comfortable. Needs an airtight home, ducts and space for the unit. |
New builds and renovations
In Flanders, new builds and major renovations must meet ventilation requirements under the EPB (energy performance) rules. For an ordinary renovation ventilation is not always mandatory, but it is strongly advised once you replace windows or insulate: otherwise moisture stays in the home.
System C is often the easiest to install in a renovation. System D needs more ducts and space, but delivers the most comfort. We will look together at what is possible in your home.
Maintaining your ventilation
- Clean or replace the filters of a system D regularly, as the manufacturer advises.
- Keep vents and valves free of dust and never block them.
- Have fans and ducts checked from time to time.
Frequently asked questions
Do I need ventilation if I open the windows now and then?
Opening windows airs a room briefly but does not ventilate continuously. A ventilation system removes moisture and stale air day and night, also when you are away or asleep.
What is demand-controlled ventilation?
Sensors measure humidity or CO2 and adjust the fan. So ventilation happens only where and when it is needed, saving power and heat.
Is a ventilation system noisy?
A well-designed and properly balanced system is barely audible. The choice of unit, ducts and location make a big difference.
Request a free quote
Dirk and Pieter-Jan will gladly send you a detailed quote. Free and without obligation.
