Ventilation and heatwaves: should you switch off your ventilation in summer?

When the heat sets in, one question comes up again and again: should you switch off your mechanical ventilation to stop hot air from coming in? The answer is more nuanced than it seems. Ventilation is not designed to cool, but to renew the air — an essential role, even in the middle of a heatwave.

What is mechanical ventilation really for?

Controlled mechanical ventilation ensures a permanent renewal of the indoor air. It removes moisture, pollutants, CO2 and odours, while limiting condensation and mould. Switching off your ventilation entirely means degrading the quality of the air you breathe.

Should you switch it off during a heatwave?

As a general rule, no. Ventilation does not heat up the home: the airflows are low and serve only to keep the air healthy. However, you can adopt a few good habits:

• Close shutters and windows during the hottest hours to keep the coolness stored overnight.
• Air the home early in the morning and late in the evening, when the outdoor air is cooler.
• Let the ventilation run: it keeps removing moisture, particularly in the bathroom and the kitchen.

Single-flow, dual-flow ventilation: what's the difference in summer?

A dual-flow ventilation system recovers heat from the extracted air to pre-heat the incoming air in winter. Some models feature a summer bypass which, in summer, bypasses the exchanger to bring in cooler night air without heating it up. It is a real asset for summer comfort, provided it is properly set up.

Ventilation and air conditioning: thinking about comfort as a whole

Cooling a poorly ventilated home means treating the symptom rather than the cause. A good strategy combines healthy ventilation, effective insulation and, if needed, correctly sized air conditioning. Discover how to choose the right air conditioner and how to set your air conditioning during hot spells.

Unsure about your installation?

Proclimo works on both ventilation and air conditioning. We check your airflows, the condition of your ducts and the overall consistency of your installation. Contact us for a diagnosis, or discover our expertise.