The Green Homes Grant is a new scheme that covers two-thirds—or up to £5,000—of the installation costs of various green home improvement measures. Insulation and low carbon heating solutions are part of the primary measures. Secondary measures include, among others, draught-proof uPVC and double glazed windows.
There are other grants that can help support your home improvement projects, for example, the Renewable Heat Incentive or the Smart Export Guarantee, though those are not installation grants.