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BFRC  ‘A’ Rated Window

The following factors affect the whole window U-Value:

• The type of glazing material.
• The number of glazing layers.
• The size of the cavity between the glazing layers.
• The type of gas in the cavity between the glazing layers.
• The design material and type of frame and the other components.

Note: Always ensure that a quoted U-Value is for the whole window and not simply for the glass.

Glazing Materials.

Clear float is glass that has previously been the major material used for windows in houses. Advances in glazing technology mean that special glass is now available to control heat loss through the window.This lowemissivity (low-e)glass has special surface coatings to reflect heat back through the window. The low-e coatings reflect heat that is normally transmitted through clear glass, allowing the full amount of light to pass through. This type of glass is now standard under the building regulations for most homes in the UK.

Layers of Glass and Air

The traditional approach to improving the energy efficiency of a window has been to increase the number of layers of glass and air. Double or triple-glazed windows have insulating air or gas filled spaces between each pane. Each layer of glass and the air spaces resist heat flow. The width of the air spaces between the panes is important, air spaces that are too wide have higher U-Values and allow too much heat transfer.

WHY YOU SHOULD SELECT ENERGY EFFICIENT REPLACEMENT WINDOWS

Highly energy efficient windows are manufactured with inert gases (Argon or Kyron)in the spaces between the panes because these gases transfer less heat than air.

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SELECT ENERGY EFFICIENT WINDOWS TO IMPROVE COMFORT AND REDUCE GREENHOUSE GASES

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For further details on the BFRC, visit the British Fenestration Rating Council website at  www.bfrc.org produced by the British Fenestration Rating Council (info@bfrc.org) and supported by the Housing Energy Efficiency Best Practice programme.

Frame Materials.

Window frames are available in a variety of materials and the frame material can be selected for price, maintenance or visible appearance. Any frame material can produce energy efficient windows if designed correctly. For consumers, it is important to get the most energy efficient window from the frame material that is chosen.

New Technology.

New technologies are being used to develop and improve the energy efficiency of windows. Typical of these is the concept of ‘warm edge’ glazing to reduce heat losses at the edges of the glazing unit. This improves the BFRC rating. Irrespective of these technology improvements, the BFRC rating system will be applicable and will allow consumer s to select energy efficient windows with a minimum of effort.

To compare BFRC rated windows, simply look at the label and compare the ratings. Select the window with the highest rating for the best energy efficiency and the lowest heating loss.

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