The Window Energy Rating is a government standard to rate the efficiency of all new windows. It gives and indication of how well the window will:

• Help contain and conserve heat in the winter
• Cool during the summer months
• Keep out wind
• Resist condensation 

Every new window comes with a Window Energy Rating label which allows consumers to compare the energy efficiency of a particular product and therefore make informed choices about which is best.

The label clearly shows three areas of assessment used to rate windows for efficiency:

1.      Thermal transmittance (U-value) - This measures how well the window stops heat escaping through it and is a comparable value against a standard window.

2.      Solar Factor (g-value) - This measures how well the window will block heat caused by direct sunlight. Measured between 0 and 1, the lower the solar factor the less heat gain the product will give.

3.      Air leakage (L50 value) - This indicates the air leakage factor. Air leakage makes little difference for good quality windows, but for leaky windows the impact is significant.

For further information on Window Energy Ratings contact us or visit the BFRC (British Fenestration Rating Council) website