Overview
- For bathrooms with windows, keep the door closed after showering, squeegee walls and floor, then open the window wide for a short shock ventilation period typically 3–10 minutes to expel moist air.
- Windowless or interior bathrooms need a properly sized mechanical exhaust system following DIN 18017-3 with typical design flows around 40 or 60 m³/h and features such as humidity sensors and adjustable run-on time.
- Authorities set a practical indoor target of about 40–60 percent relative humidity and warn that surface humidity can reach roughly 70–80 percent during or after showers, which is where mold can begin to grow.
- Use simple tools to check conditions: a digital thermo-hygrometer for room humidity, an infrared thermometer to spot cold surface spots and measure walls, and keep large furniture about 8–10 cm off exterior walls to improve air circulation.
- Recent weekend guidance reinforced routines such as morning ventilation for bedrooms (about 5–10 minutes), heating rooms to roughly 16–18 °C, and treating visible surface mold with cleaners while replacing deeply rooted or recurrent silicone joints when cleaning fails.