When it rains outside and the humidity is high, ventilating sometimes seems pointless: the air coming in feels damp and clammy. However, ventilating during rain is usually still beneficial, as long as you know what to look out for.
Why ventilating during rain feels different
Outdoor air often contains a lot of water vapor when it rains, but that doesn't tell the whole story. What matters is the amount of moisture in grams per cubic meter, not just the percentage you see on a weather app. Cold, rainy outdoor air often contains less moisture than the warm air inside, even if the relative humidity outside seems higher. As soon as that outdoor air enters and warms up, the relative humidity often drops again.
When opening windows really does make sense
During a normal rain shower with a moderate outdoor temperature, you can continue to ventilate without any problems. Crack the window open instead of opening it fully, so that no water blows in, and ventilate briefly and more often rather than all at once for a long time. This keeps the air circulation going without cooling your home down too much.
When it's better to wait
During a warm, muggy rainy period, such as a summer thunderstorm, the outdoor air can indeed contain a lot of moisture. In that case, ventilating actually adds extra moisture to your home. Look out for these signs that ventilating alone is no longer enough:
- Windows that continue to fog up on the inside, even some time after ventilating.
- A musty smell that won't go away, even with the window open.
- Walls or skirting boards that feel damp.
- Laundry that just won't dry indoors.
Combining ventilation with dehumidification
On days when it is consistently damp outside, such as during a long rainy period in autumn, it helps to supplement ventilation with a dehumidifier. It removes moisture directly from the indoor air, regardless of what is happening outside. We recommend using the Dynter AirPure DH251 dehumidifier for these types of situations: this way, you keep the humidity in your home under control, even when ventilating alone is not enough for a while.
In short: ventilating during rain is usually still a good idea, as long as you do it smartly. Adapt your approach to the situation and use additional dehumidification during prolonged damp periods. View the full range at dynter.eu for more solutions for a healthy indoor climate.