Thermal test results - secondary glazing
A thermal window insulation test carried out on the aluminium secondary glazing unit by the Interver glass testing centre * is summarised as follows:
- existing primary window - timber, 4mm glass, putty glazed
- cavity - unsealed 85mm
- secondary window - aluminium hardwood subframe, channel glazed, Pilkington K low emissivity glass
Thermal test results summary
- the combined secondary glazing thermal insulation U value for this configuration was 1.868 W/m²K
- using 6mm Pilkington ‘K’ low emissivity glass gives 1.5 W/m²K
- this will be equivalent to a WER rating scale of B or C
- using double glazed low emissivity glass will give a window insulation rating scale equivalent of A
* The thermal test results certification are available on request