Guest post by Kevin Ahern
In my recent quest to understand the BFRC rating scheme, I seem to have misunderstood a lot of what the scheme is all about so I thought I would try to simplify my current thoughts in the topic.

The BFRC claim that A rated windows are net heat providers of your home. Ref. Giles Willson (at Glassex), Maurice Levitt (consultant and physicist), various correspondence, Graham Hinett (Fensa Times Dec 09) et al, and I am sure, many others, on numerous occasions, yet the BFRC guidance notes explain that the scheme is purely a comparison for windows and NOT an absolute performance measurement.
You see my confusion?
The document that explains the calculation of the formula (that has been peer, industry and academia reviewed) suggests that the sun provides more power in Aberdeen than it does in Plymouth. You see my confusion?
The same document goes into great detail about a Dutch reference house and quotes a number of British and European standards (and uses them negligibly) but does not state the reference source of the solar data that it uses. Calculations from the ASHRAE standards in the US suggest UK solar flux of up to 275 KWhrs/sq mtr (South facing) and 15Kwhrs /sq mtr (North), yet the BFRC manages to arrive at an average of 218.6 Kwhrs in their formula.
You see my confusion?
The scheme has been proposed as the only method of compliance to the 2010 part L regs, yet its administrators do not appear to grasp the issue of whether the WER is an accurate energy assessment or a marketing window comparison tool.
You see my confusion?
We are now being asked to pay lots of money to the BFRC for the privilege of having our products and businesses assessed to this compliance criteria in return for a colourful piece of paper, in which the resultant rating is neither a comparison or a net heat balance figure, or both.
You see my confusion?
Those amongst us who are actively selling A Rated windows to the public as net heaters of their property, could well be actually mis-selling and telling our customers lies (if the BFRC guidance notes 2007 are still valid). Could the customer sue you if your salesmen sold your windows as providing more heat than they lost?
You see my confusion?
Now the easy bit, this scheme has been purportedly government supported and designed to help the general public better understand the products we are selling them, ironically, along the way the BFRC appear to have forgotten the fundamentals of what their rating scheme is!
On the positive side, at least the scheme has the potential to be the only tool for the government to police our domestic replacement window industry, and a further benefit, by a strange coincidence (with the amount of solar gain claimed in the formula), it would also seem to offer an extended shelf life to some of the older generation Low E glasses, that, while not offering the best U values, let just enough more sun in to balance that problem out!
You see my confusion?
I have attempted to address some of these issues with the BFRC, but unfortunately, they give the impression that they are the scientists and therefore know best. The technical responses would appear to be based on the smoke and mirrors approach and actual answers very difficult to get to.
To summarise, I think the scheme has fallen between 2 camps, energy rating and window comparison, but wants to be seen as all things to all people. The problem lies in the application, accuracy and authenticity of the solar data , which for the purpose of windows in this heating dominant climate, is of limited value and should be thus be ignored anyway. The only data on the certificates, should be the window characteristics, (U and G values), and if the government wants to reduce fuel consumption it should insulate and use U values.
Any winter solar benefit (or summer overheating cost) is so dependant on specific site installation criteria (window size, orientation, trees, neighbouring houses and any other shading) that it has little or no place in a national window rating scheme for the installation of product into existing housing stock.
Ask yourself a question. Low iron glass, why ? Is this marvelous UV transparent product such a benefit to our society that we have long neglected it at our cost? Or is it just another gimmick to scrape a few more theoretical numbers on to our colourful pieces of paper?
Are we as an industry doing our bit to help James Strawbridge save the planet? Are we as an industry helping the government with the building regs 2010 Part L implementation?
Or, as some may argue, is the window industry taking the Mick out of Mr Strawbridge, the building regs, you and me, and worst of all, the consumer?
You see my confusion?
Kevin Ahern