Our WER labels are designed to be consumer friendly, avoid technical jargon and use easy to follow graphics that aid the sales process. Our label has been designed to make yours and your customers’ marketing stand out.

With the Certass TRR Scheme, you can have unlimited WER labels in your company name, thus ensuring the promotion of your business identity in the marketplace. It also ensures that you can best meet the needs of your business by easily changing window specifications.

This will allow your business to lead and secure the best and most competitive deals available to you at any one time, meeting your customer expectations whilst placing you in a better position to take full advantage of new technologies.

Our unique consumer friendly WER label is easy to understand with simple to follow graphics. The unique light energy transmittance and heat retention graphics assist in the sale of triple glazed units.

Often triple glazed units do not perform well with the WER rating methodology as light transmittance is reduced due to the third pane of glass. With our simple to follow graphics the beneficial effect of the improved U-Value is demonstrated clearly for all to see.


Scheme Pricing

All TRR members are also member of the Certass Trade Association for one low cost fee. For more on our Trade Association visit

Fabricator & IGU manufacturer

Only £39 per month

Includes unlimited labels using our simple online calculator, or submitted thermal calculations.



Trade Frame Supplier

Only £29 per month

Includes unlimited labels using our simple online calculator, or submitted thermal calculations.


Only £24.95 per month

Includes unlimited labels using our simple online calculator, or submitted thermal calculations.


All prices exclude VAT

Additional Information

Window Energy Ratings

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 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.

Energy Rated Doors

Become accredited by completing the following simple steps >

  • Register with Certass Thermal Rating Register by clicking the apply now button below
  • Provide an air leakage test report for the doorset at 50Pascals by a UKAS approved test house.
  • Provide a simulation report of the doorsets thermal properties to sizes laid out in BS EN 14351-1:2006+A1:2010.
NOTE: Certass does not carry out simulations or air pressure testing. Only approved simulators or air pressure tests will be accepted. Make sure you contact Certass prior to gaining this data to ensure it is an accredited source.

What costs will I incur to become accredited?

  • Certass will charge you an annual fee which will allow you to issue Energy Rating labels.
  • You will be required to pay for an air leakage test report.
  • You will incur the cost of providing the doorset(s) for that air leakage test(s).
  • You will incur the cost of simulations/analysis that determine scores which establish ratings.
  • Any costs associated with the auditing body, which will be either TRR or a body approved by TRR.

CE Marking

The CE mark is a common place sight on today’s consumer electronics as well as a host of other products we all use every day. The Construction Products Regulation now brings mandatory CE marking to glazing products as from 1st July 2013. 

The manufacturer of the window/door product is the company responsible for the CE marking of the window/door product.

The CE Mark applies to the complete product, i.e. the whole window (both frame and glazing unit).

So, are you a manufacturer or installer?


If you as an installer purchase a window including glass from a single supplier under one order, then your supplier is the manufacturer and responsible for providing you with a CE Marked product as from 1st July 2013.

In this case, all you need to do, from the 1st July 2013, is make sure you buy the complete window product with a CE Mark from your supplier (the manufacturer).


If you purchase the window frame and glazing unit from separate suppliers (or manufacture both) then you are deemed to be the manufacturer, as you are buying components (each of which should be individually CE Marked) and you must CE Mark the completed whole product.

In this case, you will need to know more about CE Marking. The following information outlines what you need to do next.

The Thermal Ratings Register has developed a CE Mark calculator suitable for micro enterprises.

A micro enterprise is defined in European legislation as a company with fewer than 10 employees with an annual turnover/balance sheet not exceeding 2M Euros (for those of you that fall outside this we have partner companies that can help).

The CE Mark calculator is only available to TRR members. If you are a member of the Certass Competent Person Scheme and meet the above definition of a manufacturer then joining the TRR will give you the required CE Mark as well as access to our industry leading simple WER calculator.

NOTE: You will need to have Factory Production Control System (FPC) in place to the requirements of BS EN 14351-1:2006 +A1:2010 (there are a number of companies that can supply this, in some instances for free).

Still have questions?

Visit our FAQ for more information.