Window Energy Ratings

1: What is Window Energy Rating (WER)?

The window energy rating is the objective method used to assess the total energy performance of a window; it takes into account the materials used (glass, framing materials etc), the air leakage and the solar gain to determine the rating which expresses the energy efficiency of the product. The determined value will place the window design into a rated band (A to G). The rating compares standard size windows; this provides a simple method of comparing different products from either the same supplier or from different suppliers. Most of you will be familiar with the Energy Efficient label and A-G rating on "white goods", like refrigerators, which operates on the same principle as that for windows.

2: How is energy saved by fitting WER windows?

When you compare different values within the BFRC window energy rating scheme, the closer to A rating the better the energy saving i.e. A rated is more efficient than a G rated window. Similarly, if an A-G rated window were compared to a single glazed window with a worse air leakage rate and poorer energy performance of its components, a significant amount of heat would be saved through the energy efficient replacement windows. With less energy being lost, the householder would not require to heat the building as much and therefore save fuel, benefiting from the associated reduced heating costs, while at the same time contributing to reduced carbon emissions.

3: What are the benefits for consumers?

The BFRC window energy rating scheme provides the consumer with a a straight forward independently monitored method of comparing the energy efficiency of different windows either from the same supplier or alternative sources. The consumer can decide the level of energy efficiency they would like. Once fitted the better insulation will means less demand to heat the propertyand less heat loss, therefore saving money and carbon emissions. The consumer is provided the tools to make an informed choice on their replacement windows.

4: What are the benefits for suppliers?

As a window manufacturer or installer; having your window systems window energy rated will provide an independent means of demonstrating to the consumer how energy efficient your products are. When initially simulated or tested you may not see the marketing potential of promoting a low rated window. However, by working with the simulator you may be able to utilise more energy efficient component technology, which, when incorporated into your product, will improve its overall performance. The Building Regulations for all regions of the UK reference the BFRC Window Energy Rating scheme as an acceptable method to demonstrate compliance with their thermal performance requirements for replacement windows as an alternative to U-values. Manufacturers with registered ratings will have their details on the BFRC web site, with a search faclity to assist consumers seeking energy efficient windows to identify potential window replacement companies.

5: What are the benefits for specifers?

When designing a building or undertaking refurbishment work on a building, most owners or occupiers want to know the running costs, with fuel prices making a major impact on the costs for running a building. A specifier may specify energy efficient windows with a higher rating, and while these may have higher initial cost due to the advanced technology, they can be demonstrated to save on the actual running costs of the building over its lifetime, based on an independent measure of energy efficiency.

6: As a supplier of windows – who would determine the window energy rating of my windows?

Window suppliers should contact one of the BFRC Certified Simulators, details of whom can be found on the BFRC web site www.bfrc.org. The simulator will discuss your product range and will be able to quote you for undertaking simulations on them. Once you have undertaken a simulation, the simulator will be able to discuss the results and provide suggestions for improving your product to achieve an improved rating. Once you have completed the simulation process, you will need to contact one of the BFRC approved Independent Agencies(also available from the web-site) who will quote you for undertaking a site inspection to ensure you are able to supply the windows being rated. As part of this process, they will visit your premises and undertake an audit trail. Once you have been approved by the Independent Agency, you can register your windows with BFRC Ltd, who will produce unique labels for your product and enter your company details and product range on the BFRC web site.

For more information please visit www.bfrc.org