Hi @Cameo that's great feedback and will be very useful to me as I weigh up the different options and companies.Just got our windows and two doors replaced(went upvc in the end). Found the whole Experience quite stressful As it’s a huge amount of money and the quality of fitting seems a bit pot luck.
Whilst low u values will help with energy efficiency the quality of fitting and attention to detail is way more important IMO, especially sealing around the windows.
we went with a small local company in the end and the fitters did a decent job I think, certainly spent a fair bit of time on the fitting and very tidy finishing on the inside with no repainting or decorating required except for one minor piece on a reveal. The crew had all been with the company about a year and seemed competent, although my heart was in my mouth when they installed a large feature window (1st floor level) with a crane, as it was swinging around And the crane driver commented that it looked like the guys hadn’t done much crane work
As above i think there is a huge element of getting lucky with the fitters.I got One highly recommended company(from a builder I know) but the price was almost double I paid (for only a slightly better UPVC profile) but their fitting is supposed to be second to none, but couldn’t justify the cost(we have about 27 windoes so it was expensive)
The company I went with is owner managed, and all fitters are employed directly by company and the owner whilst only on site one day seemed to be very carefully monitoring progress throughout. (No pushy sales talk and very organised, offered good advice on where to put handle etc, very accommodating with my requests for detailed specs etc.. I’d say he thought I was mad as I can go into overdrive with research)
I’d recommend getting insulation on the window reveals at the same time to get a better seal and avoid thermal bridging, we didn’t in the end because timings didn’t work out, we got insulated plasterboard in the upstairs of the house around the same time. (look up aerogel and airtight tape for more detail)
in terms of u value it’s u of the window rather than the glass you want to focus on as others have pointed out. However unless you are going passive (or the house is extremely air tight) I’d say very little difference between a u value of 0.9 or 1 and 0.7,0.8 In term of comfort and energy usage.
you Should get specs of profiles (frames ) and glass, we got deceunick profiles and pilkington optitherm glass. Other common profiles are kommerling and veka( seems to be a bit better with more chambers in frame). Seems hard to get definitive info. on what’s better though
lastly I wouldn’t be too focussed on BER, air tightness and attention to detail of any improvements or upgrades more important
In particular, thanks for the heads up on the specification details to look out for, will help a lot!
In terms of companies, I have ruled out the bigger fitters as I feel they all have way too high a ratio of negative reviews.
Would you be open to sharing the name of the company you selected? Thanks
Too much research is always a good thing. I replaced the patio doors at the back a few years ago and just went with the recommendation from the window fitter. I now have no idea what the U value is and it occurred to me afterwards how crazy that was given that I wouldn't buy a laptop without looking into the technical specification in great detail.