Wonderful World of WERs
Guest Post by Kevin Ahern
Just over a year ago, I happened across a document that was telling the world how good a well known branded hardcoat low E glass could be, but when I looked further, it told me that the units I was buying (softcoat 1.1 U- value), were just not as efficient! Now, I have a reasonably technical background in the industry, but this just did not make sense at all.
After a fair amount of research and lots of question asking I came to the conclusion that something was very wrong with the
BFRC window energy rating scheme. Some of you may have seen some of my rantings on blogs such as Matthew Glovers ‘
Renegade Conservatory Guy’ and letters to
Fenestration News, and are aware of the issues in the scheme that concern me, but some may be yet to experience the Wonderful World of WERs.
The scheme was noted as voluntary, a kind of marketing scheme that some players love to use and will exploit, fine, however, the stakes became a little more serious when the CLG published the proposed amendments to the Building regs Part L (conservation of fuel and power). All of a sudden the only proposed method of complying to the building regs for the replacement window industry was to buy into the BFRC scheme and pay for certificates to prove your windows were at least a C rating.
The idea being, that the better the rating, the less heat it loses, the problem is that in the formula used by the BFRC, the solar gain is so exaggerated that the A rated windows actually show a net heat gain through your windows. You may have heard BFRC directors state that A rated windows are net heaters of your house, you may have read it in print, you may even be selling your windows as just that. Come on, lets get real here, we sell windows, not radiators, yes there are different levels of insulation and U values, but they do not heat your house. To have a solar factor in the calculation formula that allows that claim to be made is ludicrous and to have it legislated as a compliance measure is farcical.
I believe that the scheme is not based on technical accuracy at all, but may have far more to do with commercial advantage.
How many in the industry have scrutinized the formula and realized the consequences of it’s implementation.
When the yearly heating savings benefit from upgrading from a C to an A can be as little as £1.20 /sq mtr of window, surely there is little point in having grades, why not have pass or fail, why not specify U-values?
If the industry thinks they are helping the consumer to choose energy saving products with this scheme, they are sadly mistaken, I can show C rated windows with a 1.8 U-value and a D rated window with a 1.6 U-value, I know which window I think is better, but the rating system seems to contradict me.
The window profile and glass specification is calculated to minute detail for the certificates , the slightest change of reinforcing or polystyrene up your channels can alter your rating band , but put any one of 15 different obscure glasses all with differing ‘g’ values and the rating is assumed to stay the same!
‘Double Glazing’ as a replacement industry has had some bad press in the past but seems generally to have cleaned up it’s act , why should we now allow that to be jeopardized by a hair brained energy rating scheme that by it’s own admission doesn’t actually rate the energy through a window.
I would urge the BFRC to publish the reference source for the solar data used in the formula, then, we could all judge for ourselves.
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on Friday, March 5th, 2010 at 6:45 pm and is filed under Double Glazing Industry, Guest Posts.
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The world has gone mad!
The BFRC need to have a more open approach to glass products in the market. For example ‘Low Iron’ glass is very much like Clear glass & hold the same properties regardless of manufacturer. If the simulators remain to specify that the glass products must be from the same manufacturer, then this is a serious problem for the Independent glass manufactuers. The levels of glass stock will become overwhelming, needing to stock 3 types of ‘Low Iron’ glass is absolutely ridiclious! BFRC lets publish some clear guidelines, then we can all be simulators.
I couldn’t agree more. The whole solar gain element of the WER scheme seems to me like so much smoke and mirrors, designed to add some apparent ’science’, but which in reality creates a scheme in which the rating does not correlate to what customers actually want.
U values seem to me to be more easily understood and to tally better with what consumers want, which is a product that insulates well.
And while we’re on the subject, the guidance for issuing WER certificates seems very confused. There is much talk about ‘A rated Jobs’ (etc), but as I understand the scheme, no such thing exists as ratings apply to individual windows not to a whole house full. Fabricators are, however, issuing certificates for complete jobs, which may well include non-WER products (including doors, and where are we with a scheme for those??).
There is no doubt that having a scheme for energy rating is required, but sadly what we have at present is incomplete, arguably over complex and in my view poorly defined. I think the public deserves better.