Briefly…
Window energy ratings are A B C D E F
Just like the labels on your new fridge/ washing machine.
A is the highest rating (most efficient)
F is the lowest rating.
Building Regulations
From 1st October 2010, the new building regulations require that a MINIMUM of C rating is used (or at least a U Value of 1.6 w/m2).
Our standard windows comply with the minimum C rating, however, we can easily upgrade to B rating or A rating for a small additional cost.
The Energy ratings A,B,C,D,E are rated on a scale according the energy lost through the window in one year. This is expressed as a negative number of KWH /M2/year
Kilowatt hours, Heat loss, per square metre of window per year.
Energy rating scale |
KWH/Sq Metre/Year (heat loss) |
A |
Loss of 0 Kw/H per year or a gain of ‘x’ Kw/H per year (ours = A + 10, is gain of 10Kw/H per year) |
B |
Loss of 0 to 10 Kw/H per square metre per year. |
C |
Loss of 10 to 20 Kw/H per square metre per year. |
D |
Loss of 20 to 30 Kw/H per square metre per year. |
E |
Loss of 30 to 50 Kw/H per square metre per year. |
F |
Loss of 50 to 70 Kw/H per square metre per year. |
The heat loss of the window will depend on both the insulation value of the frame AND the insulation value of the glass unit.
All of our window frames are insulated, making it more cost effective to get highest rating.
Frame Details
C rated (minimum Building Regulations)
Insulated Frames, Low E glass with Aluminium spacer bar
B rated
Insulated Frames, Low E Glass , Argon Fill, Aluminium Spacer
A rated (ours are plus 10)
Insulated frames, low E glass, Argon fill plus insulating Swiss V spacer bar.
Swiss V spacer bar, is a new fibreglass, insulating spacer bar, which eliminates cold edge around glass unit perimeter where condensation can occur. It only costs a few pounds extra per window.
The difference between C minus 20 and a Good A plus 10 is 30Kwh per Sq metre per year year
So for a window 2metres x 1 metre = 2 Sq metres this would be 60kw hours saved in one year
Or roughly £8 per year, based on 13p per kw/hour.
If you are replacing your window anyway, then the small additional cost of upgrading to A rated can be easily recovered in 2 years, then the cost saving benefits continue, as fuel costs rise.
Documentation
We have copies of Full simulation reports from Synseal Extrusions Ltd.
for both The C and the A ratings.
Each report is 10 pages and can be viewed at our showroom.
Copies are available by post on request.
The reports are prepared by an approved Simulator (080) by British Fenestration Registration Council BFRC reports noSYN-00124-3 SYN-001246
