We’ve all done it – woken up in the morning, pulled back the curtains to look at the (hopefully gorgeous) view outside, only to be confronted with… a misted-up window.  So begins the task of wiping it off to stop those pesky water droplets becoming a breeding ground for bacteria and turning your window frames black.  But what causes condensation?  And what can we do about it? 

First of all, we need to understand just what’s going on – what’s causing our windows to mist up? 

We’re getting better and better at insulating our homes and preventing heat from escaping into the outside world.  In general, that’s a good thing, keeping our heating bills down and keeping us warm.  Unfortunately, it also means that our homes are becoming more like sealed boxes – heated air can’t get out, but fresh air can’t get in either.  That’s a problem, because as we breathe we exhale moisture into the air. 

Overnight, we each breathe out about half a pint of water.  And that water has to go somewhere.  As it travels about the room, if it hits a surface that’s cold enough (like the glass in your window), it will turn from a vapour to a liquid – creating condensation. 
 So what can we do about it?  Of course, having high performing windows (like we sell here at Red!) will help to a certain extent – better insulated glass will mean it isn’t such a cold surface for the water vapour to land on and condensate.  But that isn’t really a full solution – even the best windows will still condensate in the right circumstances.  

The simplest and best solution is a very natural one – open your windows!  

That doesn’t mean they have to be wide open – just open enough to allow the moisture-saturated air to be exchanged with enough fresh air to reduce the moisture content.  If you have trickle vents in your windows, make sure they’re open, and if your windows have a night-vent position (especially one that is lockable, if you’re particularly security-conscious), just use that. 

Easy peasy! 


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