The most recent illustration of the likely energy savings generated as a result of retrofitting existing housing stock with energy efficiency measures can be found in the Green Deal Impact Assessment (IA), published alongside the Energy Bill on 8 December last year, energy efficiency minister Gregory Barker said in a written answer.

This development stage IA presents two illustrative scenarios for the installation of energy efficiency measures into the existing housing stock between 2013 and 2020 resulting from possible future secondary legislation, he pointed out.

Detailed assumptions related to the energy saving per measure are presented in the annexes to the IA, with these assumptions being applied to the illustrative scenarios to calculate the total energy savings generated over the life-time of the measures installed.

The two scenarios assume different levels of consumer take up of a variety of cost-effective insulation measures. The range of total energy savings estimated in the two illustrative scenarios in the Green Deal IA is 64,000 to 87,000 TWH/year from 2020, over the lifetime of all the installed measures.

But, he warned, the results "do not represent the total amount of energy saving that would result from the retrofitting of the entire housing stock."
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