Self Certification
for Glazing >

As part of the Kyoto agreement, the UK Government has made commitments to reduce emissions of greenhouse gases, such as carbon dioxide, which are harmful to the environment.

Generating the energy we use to heat, light and cool our buildings accounts for almost half of the carbon dioxide emissions in the UK.

Energy efficient windows will help to contain and conserve heat within the home, keeping out wind and rain, resisting condensation and yet allowing natural “free” energy – the warmth of the sun – to heat the home. They can be made using any frame material including aluminium, PVC-U, steel or timber.

The rating formula used to calculate energy efficient windows was determined by following the methodology adopted by the European Window Energy Rating Scheme, EWERS, which was developed as part of the EU ‘Save’ initiative


Energy Ratings explained >

  • A window’s rating is determined by a mathematical formula. The values used in the rating formula are based on the energy balance of a notional house through an average UK year, with notional window sizes and configurations.

  • The performance of a real window, in a real building, will differ from that of the notional window used for the rating calculation. In some cases the performance will be better and in others it will be worse.

  • The purpose of a Window Energy Rating is to allow one window’s energy performance to be directly compared to another under standard conditions. All new and replacement windows either have to be rated C or better or have a U-value of 1.6 or lower.

The Thermal
Rating Register >

The Thermal Rating Register provides a simple system to demonstrate the energy efficiency of varying window and door designs.

Using a simple colour coded A-G rating, similar to that seen on white goods and houses; generally the higher the rating, the better the overall thermal efficiency, and the greater the savings on your fuel bills for consumers.

The Building regulations as amended in 2010 require replacement windows to be a minimum of a ‘C’ rating. The Thermal Rating Register provides details of PVC-u, timber and metal windows. The rating of windows not only takes into account the amount of heat the window loses directly, but also the amount of air that can escape through the frame, and the positive benefit of heat energy gained from solar energy.

The Thermal Rating Register gives your business the competitive edge. We provide a cost effective system to register your window designs and our rating processes are streamlined to ensure a smooth registration process.


CE Marking >

All members of the Thermal Rating Register have free access to our CE Marking calculator suitable for micro enterprises as defined in the EU directive for CE Marking.

Under the directive a micro enterprise is defined as:

  • A company with less than 10 employees
  • A company with a turnover of less than 2 million euros

The calculator works out a worse case default U-Value for a range of windows. For UK Building Regulation purposes the Window Energy Label is used for thermal compliance. Click the graphic to find out more >