Why it works
How cross-ventilation works
Short answer
Pressure differences move air from one opening, through the building and out through another.
The simple explanation
- ✓Wind can drive flow across a home.
- ✓Warm rising air can support vertical flow.
- ✓Obstructions and small openings reduce exchange.
- ✓For cooling, incoming air should be cooler than indoor air.
Why it works
This advice follows UK Health Security Agency guidance and the underlying principles of cross-ventilation and pressure.
Important exceptions
Safety, health, weather and the design of your home can change what is appropriate. Stop if an action makes conditions worse.
Related guides
Sources & evidence
Reviewed 2026-08-21
- UK Health Security Agency: Beat the heat: keep cool at home checklist ↗
Supports: Shading, ventilation, reducing indoor heat and protecting people at higher risk.
official guidance · Accessed 2026-08-21