Just a quick note for anyone interested in a 3g Upvc window that will achieve 0.8 U Value. I've recently had them installed a new build:

It's Rehau's standard 'Total 70c' window profile which (unmodified) will accept triple glazing and the two elements combined achieve 0.8.

 

It took me a while to get the exact spec as it isn't publicised anywhere but the attached spec is from Rehau's technical department:

 

 

Edited December 2, 20169 yr by Ian

Oh, almost forgot...the supply & fit price was £5k which was for 6 windows + 2 fully glazed double french doors and an unglazed front door.

Looks good - who is the supplier ..?

Just check that you like the look of them as there is very little window beading as the glass is near the full width of the frame. I looked at the same type of product but just didn't like the fact it was near enough straight up from the frame into the glass with maybe a 5-6 mm bead.

Edited December 2, 20169 yr by Declan52

5 hours ago, PeterW said:

Looks good - who is the supplier ..?

Any Rehau supplier will be able to quote but the prices I got back varied by about 30% so it's well worth shopping around. The window profiles are all standard Rehau sections but the window suppliers all buy the glass in from specialists. The glass spec obviously makes a big difference to the overall U value so it's important to stick with the St Gobain references on the sheets I posted.

3 hours ago, Declan52 said:

Just check that you like the look of them as there is very little window beading as the glass is near the full width of the frame. I looked at the same type of product but just didn't like the fact it was near enough straight up from the frame into the glass with maybe a 5-6 mm bead.

I'm really pleased with them thanks. I'll try to remember to take a photo tomorrow and post it here so you can see if it's how you imagined it would be.

Be careful with the glazing specification. I note the g value above is 0.37 which may work in some designs but wouldn't have been in mine. 0.37 would be a good choice when trying to mitigate summer overheating with lots of glazing on a Southern aspect but will be very poor for solar gain in winter. Ug of 0.5 and g = 0.5 is more common which is what we went for on N, E and W aspects. We found Ug of 0.6 and g= 0.61 worked out better (in terms of PHPP) for the Southern aspect. (There was difference in window cost from Internorm)

 

The software shown in the Rehau posting is free on the Saint Gobain website and you can play around with different coatings, gasses and glass.