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Condensation on double glazed windows - can trickle vents be added after fitting?

We have just had new double glazing. We have significant condensation on the inside and some on the outside. I have read the previous posts regarding ventilation. The fitters of the windows advised us against us having the trickle vents (basically that some people have them, some don't and there isn't a massive difference). Given that the suggested solution is to have trickle vents fitted, can they be added after the windows are fitted?

2 Answers from MyBuilder Window & Door Fitters

Best Answer

buildings have to be ventilated in order to maintain the health and well-being. Two kinds of ventilation: Rapid and background the latter ventilation can be provided by trickle vents. Rapid ventilation open the window. The need for background ventilation depends
upon the building and how it is currently being ventilated or used. good replacement window certified fitters would advise on this requirement. If a window is not well ventilated then it can lead to condensation build up which, if left, can lead to mold spore growth. Current building regulations state that it is only mandatory to install trickle ventilators within
a replacement window if there was a trickle ventilator within the existing window. (equivalent or better). it may be your window do not have sufficient insulation around them which causes cold bridging and in turn attract condensates. Check for a good seal of caulk around the new window. If there are no vents then you need to ensure air changes in the property by either rapid venting (open window) or introduce dehumidifiers / good quality vents that open when relative humidity of the property zone area is above 70 (not temperature; humidity) you can fit a passive vent system or humidistat to new or existing extractor fan vents. Passive background air bricks etc. do not cut the mustard when you dry clothes in the property or if you have lots of people living there (2 litres of water per person per night can be released in the atmosphere just from breath and sweat.. Yeuk!
Good luck


Answered 4th Feb 2016

T vents are compulsory if a room exceeds 8m2 in replacement windows.
But to your question yes they can be fitted, easiest way is to drill 8-10mm holes through the sash or frame then cover with the t vent.

but even with t vents condensation can still occur.
Look to eliminate it at source kitchen and bathroom mechanical ventilation, damp washing being dried in the house ect.



Answered 12th Nov 2014

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