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I am in the midst of retrofitting an MVHR system and am wondering what, if anything, I should do about my window trickle vents once complete. I could just leave the cover flaps closed but a) I'm not sure how well they seal (probably well enough I'm sure), and b) whilst the flaps cover the inside hole the outside hole remains open (with just an insect screen) and so cold air can still enter the window frame cavity (they're multi-chamber UPVC).

 

Whilst I am confident this MVHR system will be 'for life' I don't want to remove the potential for reversal and so thought expanding foam in the vents might fit the bill. It'll work (seal/insulate) well and I think should be removable if need be by hacking at it with a suitable tool and having a vacuum cleaner suck all the bits out.

 

Any thoughts? Even just the advice to close the vents and get on with my life?!

 

 

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take the vent covers off, stick some clear gorilla tape over the holes. would suggest masking off the outside area of the covers prior to taping as that stuff sticks! trim back after refitting covers.

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Hmm, yes, that would work and sounds less radical / more reversible. Even less-sticky-than-Gorilla-tape tape should work as the covers will both protect and keep it in place. 

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How about fill them with expanding foam as well?

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😁 To be honest I'm not exactly sure what my hesitation actually is! 

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I may have filled my bathroom window trickle with expanding fire foam. The howling gale blowing through the closed vent in the winter months from this exposed side seems to have been cured👍

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If you're using expanding foam, get some isopropyl alcohol (ebay) and use it to clean as you go before it goes off. 

 

if doing more than one or two cans, get gun grade and a gun.

 

Wear gloves or you'll end up using sandpaper to get it off your skin.

 

Ask me how I know this :)

 

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Posted (edited)

It sounds like we've been on the same training course! 

Edited by MJNewton

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Posted (edited)

As an intermediate, why not close them but use a bead of silicone around the edge of the shutter first, then wipe off the excess.

 

Then if you find it works OK with the MCHR and decide to foam it up in 1 or 2 years, you can reopen it with a modelling or Stanley knife and do the thing more thoroughly.

 

F

Edited by Ferdinand

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Yes, I could try that. Thanks everyone for the comments - all food for thought and will help decide what to do. 

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