When is the best time to open my windows?

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.

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

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.

What humidity level is too high for ventilation?

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.

Is it safe to leave windows open at night?

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.

How does OpenWindow.live decide?

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.

🪟 OpenWindow.live

Devo abrir as janelas em Porto agora?

Decisão ao vivo para Porto. Atualizada a cada 30 minutos.

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Quando é melhor abrir as janelas em Porto?

Em Porto, os melhores momentos para ventilar são geralmente de manhã cedo (5–8h) e ao final da noite, quando a temperatura exterior desce abaixo da interior.

É seguro deixar as janelas abertas à noite em Porto?

Sim, na maioria dos casos. Abrir as janelas pode baixar a temperatura interior em 2–5°C em 30 minutos se o ar exterior estiver mais fresco.

Que humidade exterior é demasiada para ventilar?

Acima de 80%, abrir as janelas torna o ar pegajoso. Melhor esperar por horas mais secas.

Devo abrir as janelas em Porto agora?

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