Question 1

When is the best time to open my windows?

Accepted Answer

Best ventilation happens when the outdoor temperature is at least 2°C cooler than indoor and humidity is below 70%. In summer that's typically early morning (5–8 AM) or after sunset. In winter, short bursts (5–10 min) of cross-ventilation a few times per day.

Question 2

Should I open the windows when it's hot outside?

Accepted Answer

No. If the outdoor temperature is higher than indoor, opening windows brings warmer air in and worsens comfort. Keep them closed and shaded during the hottest hours, then open at night when temperatures drop.

Question 3

What humidity level is too high for ventilation?

Accepted Answer

Above 80% relative humidity outside (especially when warm), opening windows makes indoor air feel sticky and can promote mould. Wait for drier hours or use a dehumidifier.

Question 4

Is it safe to leave windows open at night?

Accepted Answer

In most weather, yes. Cool night air can drop indoor temperature by 2–5°C in 30 minutes. Check the live recommendation above before going to bed; OpenWindow.live combines temperature, humidity and air quality.

Question 5

How does OpenWindow.live decide?

Accepted Answer

We compare your outdoor real-time data (OpenWeather + AQICN) against your indoor reference temperature (configurable). Hard NOs: AQI very poor, outdoor warmer than indoor, humidity > 80% in warm weather. GREEN: outdoor cooler by 2°C+ with clean air. Otherwise yellow with a partial-ventilation tip.

Should I open the windows now?

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