What should I be looking for or asking for in regards air tightness guarantee, 

so I fit my bloody expensive windows, then have an air test and they leak like a sieve, all sealed correctly around the outside, actually leaking from the opening part. 

What sort of guarantee did yours come with. 

There is some leakage through mine, primarily keyholes and openings. I noticed most when I was spraying the mist coats and had the windows masked off with drapey plastic that billowed. That said, our build retains so much heat that we're still leaving windows open during the day and have only just started closing our tilt and turn bedroom window overnight. A bit of window leakage isn't a big deal for us.

Looking for air permeability class 4 tested to EN12207 that should guarantee you the best results...

 

I'm still tempted by windows that are only class 3 but not sure to what extent this will affect my airtightness score.

Is 4 the highest class for air tightness? I recently enquired about some doors and was told it was 4(600Pa).

 

Russell, what windows did you get cos I'd be mighty unhappy too

Edited September 30, 20197 yr by Vijay

Haven’t bought any yet I’m just looking at asking the right questions 

i cannot get my head around fixing all air leakage issues everywhere and then fit a window that is a bit drafty. 

1 hour ago, Vijay said:

Is 4 the highest class for air tightness?

Yes, from 0 to 4

 

42 minutes ago, Russell griffiths said:

i cannot get my head around fixing all air leakage issues everywhere and then fit a window that is a bit drafty. 

Having windows (where it allows) that are non opening should totally fix the problem

Something else you may want to ask if you're fitting the windows/doors yourself, is about the warranty. I was told there is no warranty if they didn't install the door I mentioned above. That was ID systems