HC Deb 30 March 1982 vol 21 c74W
Mr. Porter

asked the Secretary of State for the Environment what rate of return on investment he seeks to achieve for energy conservation measures within buildings under his control.

Sir George Young

All energy conservation measures within buildings which are the responsibility of the Property Services Agency have to be fully cost effective. There is no minimum rate of return but, at present, the majority of schemes have a payback period of up to five years.