Overview
- Recent coverage on Friday reinforced the core rule: open windows only when outside air is cooler than inside to avoid bringing heat into the home.
- Short full-window airing (Stoßlüften) and cross-ventilation (Querlüften) move warm indoor air out faster than leaving windows tilted open.
- Outside solar protection such as rollläden, awnings or shutters is the most effective way to stop heat at the window before it enters living spaces.
- Architectural and passive designs can deliver large gains: the Résidence Théia in Montpellier reports about 8°C lower indoor temperatures through façade shading, airflow and night cooling.
- Simple occupant steps—open wardrobe doors when airing, use moist towels and correct fan placement, avoid daytime cooking—are low-cost first lines of defense while policy and retrofits address longer-term equity and energy issues.