What is the difference between A, A+ and A++ rated windows?
The letters are BFRC Window Energy Ratings, running from A++ (best) to E. The rating combines heat loss, solar gain and air leakage into a figure in kWh/m² per year. A+ means a rating of 10 or more, and A++ sits above that. For replacement windows in England, Band B is the legal minimum.
What does the rating measure?
- Heat loss through the window (a negative factor)
- Solar heat gain (a positive factor)
- Air leakage (a negative factor)
Does a higher band always mean a better window?
A better band means better overall energy performance, but the rating applies to one specific window configuration. Changing the glass, spacer or size can change the band.
Which band should you order?
Specify Band B to meet Part L, or A and above where customers want a lower energy rating. Ask for the BFRC certificate for the exact configuration. See our supply-only uPVC windows. Where a customer asks for A++ specifically, check the supplier’s BFRC certificate for that precise configuration before promising it.
Need a trade price? Call the trade counter on 01903 262 636 or visit us at Unit 1, Friar Walk, Worthing. We offer free delivery within 30 miles.
← Back to Supply Only Windows FAQs | See our supply only windows
