Part L compliant in-line with amended Building Regulations of 2002 for England and Wales.

The changes concerned the standards of energy efficiency in buildings and inevitably affected the specification of both new and replacement windows.

Part L aims to ensure that almost every window and door installed in houses achieves a better level of heat insulation.

It is part of the Governments strategy to reduce harmful CO2 emissions, 50% of which are generated from heating, lighting and cooling buildings