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The Certass Thermal Ratings Register

26th May 2021 - By Jason Clemmit

The Certass Thermal Ratings Register

Windows play a crucial part in the thermal performance of your home. Inefficient windows can lead to increased heat loss for your property and consequently increased heating bills. In 2002, building regulations started to include the thermal performance of windows, which led to the introduction of Window Energy Ratings (WERs). Before this, U-values, which measure the heat loss from a certain material, were the main measure of a window’s insulation, but they differ in all parts of the window, including frame, spacer, and glass.

WERs were introduced as system which were easy to understand by all, with ratings from A-G and they consider U-values, solar heat gain and air leakage to provide one overall efficiency rating.  Current building regulations state that all replacement windows must be rated at C or higher or have a U-value of 1.6 w/m2K or lower.

What is the Certass Thermal Ratings Register?

We started the Thermal Ratings Register to provide an easily recognisable system to measure Window Energy Ratings.

We use a colour-coded, traffic light system, like the one used on white goods such as fridges and washing machines, to help homeowners easily understand the efficiency of their windows.

Each window rated by our register gets its own unique label providing several figures and values including the rating level, the energy rating, the U-value, the heat loss due to air penetration and the solar heat gain.

In simple terms, this tells you how effectively your window:

  1. Contains and conserves heat in winter
  2. Keeps out the wind
  3. Resists condensation
  4. Contributes to improved sound insulation

These labels are often displayed on the paperwork that comes with the windows and can also be viewed online to make you aware of the efficiency of your windows.

Got a question?

Try our frequently asked questions.

FAQs

The Thermal Ratings Register covers installation too

However well your windows perform in terms of efficiency, it won’t matter for anything unless they are installed properly.

Poorly installed windows are a huge contributing factor to heat loss in a property, so it is crucial that they are installed by a skilled, certified tradesperson. The Thermal Ratings Register scheme is designed to show that the windows and the installation are compliant with regulations, meaning you’ll get high-performing windows and a quality installation.

Find a certified installer to fit your windows

Our online directory makes it easy to find a certified window installer in your area. All you need to do is insert your postcode and it will show you the closest installers to you.

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