Menu
Window Energy Rating Guide
Get in touch with us today to speak to our friendly team.
Window Energy Rating Guide
Choosing windows isn’t just about the view; it’s an investment in your home’s comfort, heating, and energy efficiency. But navigating the world of window ratings can be confusing. Windows now have different energy ratings based on how much heat loss occurs. This guide will answer your burning questions about energy ratings, U-values, and R-values, helping you choose the right windows for your needs.
New Windows in Bradford-on-Avon
Here in the UK, window energy ratings were developed by the British Fenestration Rating Council. In 2004, the BRFC established a ratings system for windows which ranged from A++ (most efficient) to E (least efficient). Generally, an A or A+ rating is considered good. These windows minimize heat loss, keeping your home warm in winter and reducing heating bills. Whereas an E rating means the window is at risk of losing the most amount of heat.
Spotting these ratings is generally straightforward; most windows will display as sticker with a descending colour chart from A++ to E. The sticker will also show the energy index of the window. This is determined by the air leakage as well as the heat losses in comparison to how much heat it lets in.
What is the U-value of C rated windows?
The U-value measures how easily heat passes through a window. The U-value is a calculation of thermal losses and air leakage in comparison to solar heat gains. The value of which is shown with measurement W/m2.K. The lower the U-value, the better the insulation. C-rated windows typically have U-values around 2.0 W/m2.K. While they aren’t the most efficient, they offer a decent balance between cost and performance compared to lower ratings.
What is the U-factor rating for windows?
U-factor and U-value are simply different terms for the same thing. Both refer to the window’s heat transfer coefficient, indicating its ability to resist heat loss. So, a C-rated window’s U-factor would also be around 2.0. Both are measured using the W/m2.K.
What is the R-value of energy efficient windows?
R-value, primarily used in colder climates, is the inverse of U-value. It measures a window’s resistance to heat flow, with higher R-values indicating better insulation. For reference, a window with a U-value of 2.0 W/m2.K. would have an R-value of approximately 0.5 K/W.
Things to consider are that lower U-values and higher R-values are better. A++ windows offer the best energy efficiency, but A and A+ are often more cost-effective. C-rated windows are a decent mid-range option, but less efficient than A+ and A.
Choosing the right window energy rating depends on your budget, climate, and desired level of energy savings. By understanding these terms, you can make informed decisions and invest in windows that keep your home comfortable and energy bills down.
