Woody Alan":18cabmr7 said:
Alan siad previously
Please don't take this as an attack ...
Alan
Not at all. Fair comment.
My point is that I (as do many others on the forum) take the time and trouble to carry out our own research..including seeking advice from other members on the forum. Where we get conflicting views then we search a little deeper. Many people either expect to be spoon-fed or will accept the answer that they most want to hear and then bitch like hell when it all goes pear-shaped and they do not get my sympathy.
To be fair to BC, it's not always black-and-white and without knowing the whole picture then they can't necessarily answer a question such as yours re replacement window over the telephone.
Also one has to factor in the implications of new technological advances such as multi-foil insulation (and which has been successfully used by others on the forum). This stuff has been around for a while and claims to offer significant U values albeit at a cost. It's particularly useful when you don't want to lose 6 inches of ceiling height in a pitched roof. Posit that these claims are legitimate and that the stuff works. Now, quite a few BC officers around the country have been accepting this as a valid alternative to Kingspan.
However, and this is my take on what's happening out there, the guiding body for BC have recently issued recommendations that the U values are halved (IIRC). And so now you need 65mm of Kingspan plus a layer of Trioso...which kind of defeats the object and doubles the cost. So if you had spoken to a BC officer this time last year then you might have got clearance for Trioso but if you ask them now the story is a different one. Hence the apparent confusion in information supplied.
As an aside, I've been pondering why this apparent about face and my take is that Kingspan et al have seen a threat to their market penetration. The recognised standard test for insulation is the 'hot-box' test. Multi-foil has not been through the 'hot-box' test and so Kingspan have cried 'foul'. However, when the 'hot-box' test was designed and developed, multi-foils (which rely on reflecting heat back into the room) were not around and so the hot-box test only measured heat loss due to convection and conduction. Simply not set-up to measure the heat-loss of multi-foil. So the BBA or whoever have had to issue the recommendations since the multi-foil has not been through the official test route.
So if this is true then I can imagine that the multi-foil manufacturers are trying like mad to get the hot-box test changed and that Kingspan are trying to maintain the status quo.
Sorry for the slightly off-topic direction.