You may claim this credit history for advancements to the Principal property (where you live a lot of the yr). This credit history applies to new or existing Incentivising financial commitment in renewable energy with the fifth round of Contracts for Big difference by using a £205m budget; Your responses https://freeecogrants.co.uk/how-does-an-agency-help-in-improving-your-property-after-receiving-eco-grants/