When selecting new windows and doors for your home, you’ll see a lot of information about Window Energy Ratings, including the U-rating.
If you own your home, it’s vital to understand this rating system, as it will tell you the level of insulation performance you can expect from your doors and windows, which will have a direct impact on both the warmth of your home and your energy bills.
What Are Window Energy Ratings (WER)?
First introduced in March 2004 by the British Fenestration Rating Council (BFRC), window efficiency ratings help prospective buyers to know how thermally efficient their new windows are.
In a similar fashion to the rainbow labels found on numerous household appliances to depict their energy efficiency, windows which contain the WER rainbow label help the buyer know the glass and frame have been verified by experts for thermal efficiency.
The WER scale ranges from G to A++, with A++ being the most thermally efficient. However, legislation was launched in October 2010 stating that all replacement windows must have a minimum WER of band C to comply with UK building regulations.
The window energy rating label also provides insight into the following:
Thermal Transmittance (U-Value)
The U-value measures how easily heat can pass through a material in your window. While the U-value can range across other insulating products, for windows it will be between 0.20 to 1.20; with lower U-values meaning better insulating performance.
Solar Factor (G-value)
The G-value measures how much heat from the sun can pass through a window and into your home. If the G-value of your window is low, it has better protection against infrared radiation.
Air Leakage (L-factor)
The L-factor of a window measures how airtight your window is. If your window has a low L-factor, your windows will be more draught-proof.
Energy Index
The energy index can be determined by a formula which considers the overall available solar heat gains, the G-value, subtracted by the potential thermal losses, the U-value and L-factor.
Although this is a good guide for how effective your windows will be, the actual energy consumption for a specific application will depend on factors like local climate, indoor temperature, and the building itself.
What is a Good Energy Rating for Windows?
Although C-rated windows can help you save on your bills and have been the national standard for windows across the UK since October 2010, our high-performance A++-rated UPVC double-glazed windows can help to keep your home comfortable in the winter.
With A++ UPVC and aluminium windows, you can make significant savings on your energy bills by minimising heat loss through your windows with innovative technology.
What is the U-Value of A-Rated Windows?
Standard A-rated windows provide fantastic U-values of 1.4 W/m2.K, however, you can get even better than that. A+ rated windows are able to attain U-values of 1.2 W/m2.K, and A++ Rated windows can reach U-values as low as 0.8 W/m2.K.
These windows are able to provide the best effects when the glazing specification is correct, too, as the highest-performing A++ windows will also have very low G-values which protect against solar heat gain.
Choose a Which? Trusted Trader to Install A++-Rated Double Glazing
The glass in your windows is an essential part of your home’s energy efficiency, but great glass can only work at its best when combined with window frames with a low L-factor. From UPVC frames to wood and aluminium, we offer a wide range of energy-efficient window frames which help to prevent heat loss and save you money on your bills.
For energy-efficient windows installed by Which? Trusted Traders and highly rated Checkatrade professionals, get in touch with our team today.
FAQs
Do window energy ratings apply to doors?
Window Energy Ratings do not apply to doors. However, doors can be tested for energy efficiency under DERs, or Door Energy Ratings. These are not currently recognised by the Building Regulations and there are only a number of products which have been tested.
As a general rule in terms of applying WERs to doors, a fully glazed door will always be at least A-rated, whereas a front door with a small amount of glazing will always be G-rated due to the lack of solar gain.
How much are A++-Rated Windows?
Our double glazing experts will be more than happy to supply you with a free no obligation quote for A++ double glazing for your home.
The exact cost of new windows will depend on a number of factors, including the style, size, and material used for the frame. Products from South Coast Home Improvements are made to measure and can be customised according to your tastes.
The bespoke aspect is what makes it difficult to provide an accurate cost.
Please get in touch for the most accurate representation of how your double-glazed windows will cost.
