Recognising that costs have risen since then, grant levels for cavity wall insulation and attic insulation will be increased. Heat Pump System Grants - The upfront cost of heat pumps, and the additional cost of potentially having to replace the entire heating system, may be a barrier to some homeowners seeking to adopt heat pumps. Windows and Doors - A new grant will be introduced for the installation of energy-efficient windows and doors (to replace poorly performing windows and doors) for homes where the building fabric will meet or already meets a specified minimum performance standard. 'Second Wall' measure - Many homeowners have previously availed of a grant for cavity or internal wall insulation. These homeowners may want to further improve the level of wall insulation – to make their homes even warmer and cheaper to heat (and to make their homes heat pump ready).