Depending on the energy efficiency level, up to 25% of the heat produced by your boiler escapes through the windows and doors at your house. The better insulated windows and doors is the less heat you will be losing, so you can dramatically reduce your energy bills. So it is important to understand how much your windows and doors are energy efficient. For that reason, the British Fenestration Rating Council (BFRC) hase developed the Window Energy Rating scheme.
The Window Energy Rating (WER) scheme measures the thermal performance of windows and doors on a scale from A (the best) to G (the worst). When measuring, the rating system takes into account not just U-Values, but also solar heat gain (G Value) and the air leakage rate of all the components of the fitted window. The WER is designed to allow consumers and specifiers to compare competing products using a simple and easy to understand ranking and labeling system, so you can easily choose the most suitable windows and doors for your home.
WER rating labels
The WER rating system is based on a scale of E to A++, where an A++ rated window is the most energy-efficient and E is the least. The rainbow labels use coloured bars to clearly indicate the energy efficiency rating of windows and doors.
The WER scheme uses similar rainbow rating labels to those seen on household appliances, white goods and light bulbs, which makes it easy to understand at a glance how energy efficient your windows are.
Building Regulations requirements for windows and doors
Thermal efficiency and performance of windows and doors are reffered in Part L of Building Regulations. Building Regulations Part L1B requires that all replacement windows in existing dwellings must be rated C or above and all replacement doors must be rated E or higher, except in historic properties and conservation areas.
BFRC rainbow ratings are a consumer-friendly way to demonstrate windows and doors performance. It is easy to explain that an A-rated product will perform better than a B, so BFRC rating scheme help you choose the right windows and doors in terms of energy performance.
|Element Type||Required thermal performance for replacement fittings in existing dwellings|
|Window, roof window, roof light||Maximum Uw Value 1.6 W/m2K or WER Band C|
|Doors with a glazed area of 60% or more||Maximum Uw value 1.8 W/m2K or Doorset Energy Rating (DSER) Band E|
|Other Doors||Maximum Uw value 1.8 W/m2K or Doorset Energy Rating (DSER) Band E|
Energy Performance Certificates
Government legislation requires that Energy Performance Certificates (EPCs) are produced whenever a property is built, sold or rented. An EPC contains information about a property’s energy use and typical energy costs and recommendations about how to reduce energy use and save money.
Windows and doors play a major role in a home’s insulation, so look for lower U-Values and better WER ratings and your EPC will demonstrate better energy-efficiency, making it even more attractive to potential purchasers or tenants.
BFRC Energy Ratings scheme vs U-value ratings
The standard measure of heat loss in the construction industry is a ’u-value’. It provides a definative measurement for thermal efficiency. It is a generic term and can be applied all types of building elements such as walls, roofs, windows and doors. But the consumers are increasingly focused on the energy efficiency rather than only heat loss. So, BFRC energy rating system is being popular among homeowner. Energy rating system is not a measure of only heat loss, but of overall energy efficiency, including solar gain and air leakage. Although it doesn’t provide an absolute measurement of energy performance, but it is more user friendly and easier to understand for homeowners.
In Building Regulations, energy rating system is accepted for only replacement windows and doors in existing dwellings but are not an accepted rating for new buildings. U-Values are an accepted rating system for both new buildings and existing dwellings.