Fitting trickle vents for condensation

3 Feb 2009
Reaction score
United Kingdom
I have a 1990 bungalow and live alone, do my clothes drying outside, weather permitting but in the utility room when too cold or raining.
I have fitted draught excluders around all the doors and keep all doors shut, but the windows often have a lot of condensation in the mornings in all rooms.

Would fitting trickle vents to the existing UPVC windows help the situation?
Sponsored Links
In all honesty You are better off opening a window to allow condensation to clear ( not ideal in winter I'll admit ) . Thing is drying washing indoors puts a lot of moisture in the air do baths/showers/ boiling water/even breathing ...if you eliminate it from the windows it normally just finds the next coldest point to condensate .... usually an outside wall ( behind a wardrobe or similiar ) leading to black mould eventually
The thing is I read that when the humidity level is higher outside than it is inside that is not a good idea to do.
The outside humidity now is 100% and inside 69%, so opening windows allows more humid air inside.

Today there was no condensation on the windows, that is usually the case when it has been raining overnight night.

I know drying clothes inside releases moisture into the air, so in the winter I dry laundry in the utility room and keep the door shut with draught proofing around the door and leave the utility room window open.
Sponsored Links
The outside humidity now is 100% and inside 69%, so opening windows allows more humid air inside.

That's not necessarily true, because the outside temperature is lower.
Those percentages are RELATIVE humidity.

Say it's 10 C outside and 20 C inside. Looking at:
air at 20C can hold almost twice as much water as air at 10C (2.338 kPa vs. 1.228 kPa). So the 100% saturated cold air, when it's warmed to 20C, will have a relative humidity of a bit more than 50%. So provided that you have enough heating to keep the temperature up when the windows are open, in that case you will reduce the humidity inside by opening the windows.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local