Home owners are expected to account for three-quarter of the outlays, with the public sector contributing 10% and the private services sector the remaining 15%.

The aim is to reduce the consumption of energy in buildings by 15% by 2020 and 30% by 2030 relative to 2005. At least two-thirds of energy used by buildings should come from renewable sources.

Accordingly, CO2 emissions attributed to buildings would be reduced by 60% by 2020 and 70% by 2030, again relative to 2005.

This will require insulating and retrofitting between 1.3 and 1.7 million square metres of buildings each year.

These are just intermediate targets on the way to the ultimate objective of achieving zero carbon emissions from buildings by 2050.