Energy rated windows explained

Just like your fridges energy rating, windows have an energy efficiency rating that runs from a top energy  of “A” all the way down to “G”.

So to keep it as simple as possible “D” & “C” are standard low quality windows that lose a fair bit of heat that you have kindly paid for, basically about 25% of your heating bill is wasted through heat loss from your regular standard window.

Expect “D” rated on new build extensions or as poor as “E” rated on window replacements as there is no legal requirement yet to fit any better than this. “Hopefully this will change as tougher enviromental targets kick in and new builds may eventually have to meet higher standards.

An “A” rated window basically means it there is a balance between the heat lost from the home and the heat gained from the sun. This is influenced by the low E coating on the glass, the argon gas infill, the gap between the glazing and the number of chambers within the UPVC frame.

You can rate the energy ratings of windows side by side as a +9.9  “A” rated window is better than a -5 “A” rated window. The plus figure indicating it gains more heat than it loses.

Another reassuring point is “A” energy rated windows are built better and last much longer as it takes quite a bit of quality engineering and design to produce an energy efficient window.

However a point you should consider is an A rated window is really only of benefit on windows that are south facing, as the lack of solar gain on your other elevations mean that a B rating is better value for money. However you may still want A rated energy efficient windows as they will be better built and last longer.