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Frequently Asked Questions

Will ‘A-rated’ Windows Increase The Chances Of Condensation Forming?

The Glass and Glazing Federation have prepared a consumer guide to condensation. The GGF leaflet is available to download on their website. 

What Is The Difference Between Detailed and Simplified Energy Licences?

A ​detailed energy licence is specific to one particular window.  As the components are known the rating label can display the energy index, u-value, g-value and air leakage.

The ​simplified energy licence can be applied to a collection of windows that all have the same frame and rating band but might have different component parts e.g. the glass.  Only the rating band is common, u-values and g-values could vary and therefore cannot be stated on the energy rating label.

What Is The Difference Between a Licence Holder and an Authorised Retailer?

Essentially a BFRC licence holder is responsible for the controlled manufacture of the window.  The Licence holder can cascade the BFRC licence with the rated product to an installer

An Authorised Retailer (AR) is an installer who purchases BFRC rated windows and/or doors from a licence holder.  The AR is registered with BFRC and can use the Licence holder’s label with their company name displayed (the licence number will remain constant from the licence holder to the AR)

Why Is There An Expiry Date On The Energy Rating Label?

The BFRC licence label displays an expiry date to indicate the licence holder’s period of annual subscription. The expiry date does not relate to the performance of the window or door.

Which Type of Low Emissivity Glass Is Best?

The low emissivity coating (low-e) determines how much heat is lost through the glass.  As the performance of the low-e improves the solar gain values decreases.  As the BFRC rating is an energy balance between heat losses and solar energy gains, the best performing low-e glass are not necessarily best for energy ratings.

Do Triple Glazed Windows Give Better Energy Ratings?

Not necessarily.  Windows with triple glazed units can give lower glass (centre pane) u values, however this is very much dependent upon the types of glass used. Often the additional third pane of glass will reduce the solar gain significantly. It is possible to achieve the BFRC A+ rating using double glazed windows.

Do Trickle Vents Effect The Window Energy Rating?

Energy ratings for windows and doors are to be used as a comparison between two or more similar products.  Window and doors ratings are calculated without trickle ventilators, as any detrimental effect introduced by the ventilator would be the same across all products being compared.

E.g. when considering the difference between an A rated window and a B rated window, the introduction of a trickle ventilator would result in the A rated product still out performing the B rated.

The same logic is applied to Georgian bars and leaded lights.

What Is The U-Value of an ‘A-Rated’ Window?

There is no direct correlation between U value and energy rating. It is possible to achieve an A rating with U values ranging from 1.0 W/m2K through to 1.7 W/m2K as the solar gain and air leakage needs to be taken into account.

Who Calculates The Energy Rating?

BFRC energy ratings are calculated by BFRC Certified Simulators. Simulators are trained and continuously assessed to ensure that the ratings produced are consistent. All ratings submitted by BFRC Simulators are verified by BFRC to ensure accuracy.

Will Energy Rated Windows Reduce Drafts?

BFRC assess the energy rating of a window in isolation. How the window is fitted is not taken into consideration.

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