Regulation 4 First further rule: apportionment of relevant expenditure benefiting more than one property
(1)
This regulation applies to relevant expenditure which is incurred in acquiring and installing an energy-saving item—
(a)
in more than one dwelling-house,
(b)
in a building containing more than one dwelling-house, or
(c)
in a building containing one or more dwelling-houses and one or more properties which are not dwelling-houses.
(2)
The relevant expenditure must be apportioned on a just and reasonable basis to all the properties which benefit from it.
(3)
The amount of the relevant expenditure for which a deduction is allowable in respect of a dwelling-house shall not exceed the amount which is apportioned to that dwelling-house.