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Window Energy Ratings

WER_labelWindow Energy Ratings (WER) is a straightforward system that provides consumers with a familiar grading regarding the energy performance of a window.

It rates windows within a band between A-G – similar to that used on white goods – making it easy for consumers to quickly compare the energy-efficient ranges of different glazing companies. WER bands work in the same way as they do for washing machines and dishwashers; products with an ‘A’ rating have a higher energy-efficiency than those that are rated ‘G’.

The ratings applied to energy-efficient windows refer to the complete window, and take into consideration the type of glass used, the material and construction of the frame, along with the level of air leakage and solar gain (the amount of heat that the window retains). Saveheat has been working in partnership with a number of its stockists to support their efforts to obtain high Window Energy Ratings for their energy-efficient window ranges.

Saving money is of course a key benefit to homeowners installing energy-efficient windows. A window with a high WER will retain heat better than say, standard single or double glazing. The glazing system within the window can also act to absorb the heat from the sun. With the improved thermal performance of the window, the homeowner can spend less on heating their home as less heat escapes out the window.

(It is worth noting that legislation is in place in the UK which states that windows, doors and roof lights must have a minimum WER of Band D).

The British Fenestration Rating Council (BFRC) energy performance label, click here for more information »

Below you will find information regarding the WER of energy-efficient ranges manufactured by a number of leading window companies, all using Saveheat glass. Each is listed under the type of frame timber, uPVC and aluminium.

Timber Frames

Blairs has a well deserved reputation as the leading designer and manufacturer of architectural and heritage timber windows and doors.  The company is currently developing a comprehensive energy-efficient range – incorporating Saveheatglazing systems.

Full information on the range, (which is expected to offer a high window energy rating) is expected Nov/Dec. The range is currently undergoing independent assessment.

Watch this space for information, or visit

PVCu and Aluminium

Fife-based SRJ Windows use Saveheat glazing systems across their comprehensive product range of windows, doors, porches and conservatories . The company manufacture and install their KOMMERLING PVCu window and conservatories using Saveheat glazing. Awaiting confirmation of the window energy rating (WER) for this range, the company are confident that it will very comfortably secure a minimum ‘A’ rating. (The company already has an ‘A’ rating for their aluminium window).

With an extensive product range in a wide number of finishes and materials, homeowners can be assured that what they have selected for their home will not only save them money on utility bills and reduce their carbon footprint, but will be aesthetically-pleasing and compliment the appearance of their home. (It is also worth noting that all SRJ windows and doors are fitted with the highest grade of security locking systems).

To find out more about SRJ Windows products, you can visit their website at

Merlin Network offers a comprehensive window and conservatory service covering Scotland and the North East of England. The company’s High Performance window systems, which incorporate Saveheat energy-efficient glazing, have been independently tested to achieve a window energy rating (WER) of C or above.

The advanced glass and frame technology of the company’s Maestro Symphony High Performance windows reduces heat loss from your home by up to 30%. Homeowners can turn down the heating and save money. And by using less energy to heat your home means you’ll be reducing your carbon footprint and looking after the environment. With most of your home’s heat loss occurring through your windows, it makes good fiscal sense to invest in an energy-efficient window for any home improvement projects you are about to embark upon.

For comprehensive information on Merlin’s product range and window energy ratings, visit their website at


We’re here to help

View our suggested product combinations on our applications page. If you are still unsure of the best system for your project, call us on0141 810 5010 or contact us and we’ll do our best to help.

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