As the standards of standard double glazing get higher and higher, so do the energy ratings. A rated windows on the A-G scale are now very common. It’s odd if an installer isn’t actually able to fit an A rated window! But this has led to manufacturers pushing the boundaries of what double glazing can do and pushing the A ratings even higher.

John Fredericks, who we use, supply and A+8 rated double glazing windows, Evolution get A+13 out of their Storm 2 window. There are some out there even higher than these. So given this leap forward in ratings, is it time to introduce a new energy rating to help installers and customer differentiate between low achieving A rated windows and the ones breaking the glass ceiling?

I think so. This is how I think they should be classified; any A rated window from 0-9 can be called ‘A’ rated as it is now, anything 10+ should be called AA – then the number. Just as with credit ratings agencies, when you get two A’s or more, the better. It would help the customer identify which is an even better A rated window from a standard one. Also, it will help make sure that A rated windows and their numbers don’t start looking stupid. Things will only get better in double glazing, but to start selling windows at A+30 or A+40 is going to look ridiculous!

How the energy ratings certificate would look is another thing. How would it accommodate an extra band at the top? Would it have to? Could an AA rated window just replace the ‘A’ band at the top? These are just questions, but ones that would need to be addressed if there ever was to be an AA rated window.

Should it be called something else? AA is just a suggestion I have seen by a few others online and what I have thought myself. Are there any others options we could have? Comments welcome!