Insulating or replacing windows? Plan ventilation at the same time
An insulated, airtight home needs controlled ventilation, usually system C or D, to keep out damp, mould and stale air.
Do it yourself
Sources checked on .
Older homes are often ventilated by accident, through gaps and leaks. Insulating and sealing closes those gaps, so moisture, smells and stale air stay inside unless you ventilate in a controlled way. A household produces about 10 to 20 litres of moisture a day.
The principle is simple: fresh air comes into the dry rooms (living room, bedrooms), flows under the doors, and is extracted from the wet rooms (kitchen, bathroom, toilet). It should run day and night; a cooker hood alone is not enough.
System C brings fresh air in naturally through grilles and extracts it with fans. System D supplies and extracts air with fans and can recover heat from the outgoing air. Demand control, which ventilates more when rooms are in use, also limits the heat lost.
Details
| Impact | Indirect · This saves no energy by itself: it is a rule, a service, a contract, or a health or safety item. How we rate impact |
|---|---|
| Estimated saving | Ventilation costs some heat; the benefit is healthy air and no damp. Demand control or heat recovery limits the heat lost. (confidence: medium) |
| Who acts | You (owner) |
| Needs landlord's agreement | No |
| Type | Action |
| Constant or subject to change | Constant · Good practice that barely changes with new laws, prices or services. |
Do this together with
Sources
- Ventilatie bij renovatie (in Dutch) · Vlaamse overheid (vlaanderen.be) (official source) · checked on
- Ventilatiesystemen (EPB-pedia) (in Dutch) · Vlaams Energie- en Klimaatagentschap (EPB-pedia) (official source) · checked on
- Geniet van gezonde lucht (in Dutch) · Vlaamse overheid, departement Leefmilieu, Natuur en Energie (official source) · checked on