If you install an air-source heat pump (ASHP) to heat your property, it will attract a subsidy called Renewable Heat Incentive, which is a payment to you based on how much CO2 emissions are saved by the installation of the system.   The calculation is done on the basis of the guestimated CO2 emissions numbers in your (less than 2 years old) EPC Report, taking potential savings by loft and cavity wall insulation (which you can often get done for free) into account. Naturally that means