Wet windows on the inside are one of the most visible signs that the humidity in your home is too high. Many people turn to a dehumidifier, but does that device really help against condensation on glass? The short answer: in most cases, yes, although the condition of your windows also plays a role.
Why does condensation form on windows?
Condensation forms when warm, moist air comes into contact with a cold surface. Glass is usually the coldest surface in a room, especially with single glazing or older double glazing. As soon as the temperature of the glass drops below the so-called dew point, the moisture from the air settles as water droplets. The higher the indoor humidity, the sooner that dew point is reached and the greater the chance of fogged windows, especially early in the morning or after a cold night.
Does a dehumidifier help against condensation?
A dehumidifier removes moisture from the air, thereby lowering the relative humidity in the room. Because the dew point drops as the air becomes drier, the chance of the glass falling below that point is smaller. Many people notice that fogged windows occur less frequently as soon as the humidity is structurally maintained at around 45 to 55 percent.
It is important to note, however, that a dehumidifier tackles the problem at the source (too much moisture in the air) but does not change the surface temperature of the glass. With poorly insulated windows or single glazing, the glass surface may be so cold that light condensation still forms even at normal humidity levels. In that case, dehumidifying helps to limit the amount of moisture and the severity of the condensation, but it is not a miracle cure for poorly insulated glass.
How do you know if your humidity is too high?
A hygrometer provides clarity on this. Many dehumidifiers, including models with a humidistat, show the current humidity directly on the device itself. A value above 60 percent combined with regularly fogged windows is usually a good reason to start structural dehumidification instead of just ventilating occasionally.
How quickly will you see results?
That varies by situation. In a small, well-sealed bedroom, the humidity can drop visibly within a few hours. In a larger room, or when there are many sources of moisture such as cooking, showering, or drying laundry, it takes longer before the effect is noticeable. Continuous use, rather than running it for a few hours occasionally, generally yields the best and fastest results.
What can you combine with a dehumidifier?
- Ventilate after showering, cooking, or drying laundry, even if the dehumidifier is on.
- Keep doors between a damp room, such as the bathroom or kitchen, and colder rooms closed as much as possible.
- Do not pull curtains or shutters tight against the window at night, so that air can continue to circulate around the glass.
- Wipe away visible condensation quickly in the morning, before the water soaks into the wood, sealant, or frame.
Our advice is to place the dehumidifier in the room where you see the most condensation, often the bedroom, and let it run until the humidity structurally remains below 55 percent. The AirPure DH251 dehumidifier from Dynter is suitable for this: you set the desired humidity yourself and the device continues to run until that level is reached, without you having to keep an eye on it constantly.
If the condensation still returns regularly despite lower humidity, this usually points to poorly insulated glass or a thermal bridge around the window frame. In that case, dehumidifying remains useful to limit mold and moisture damage, but the ultimate solution lies in improving the insulation or the glass itself.