EPCs & The ECO 4 Fully Funded Grant Scheme For Insulation & Heating Upgrades!
The Government, via the Department Of Energy (DOE), wants to reduce carbon emissions in domestic homes. The only way they can achieve this is by boosting the energy efficiency of homes so that they retain heat more effectively, meaning that homeowners & tenants use their heating less, or transition to renewable heating, thus reducing their carbon footprint.
Renewable technologies and insulated homes is the only way to achieve this which is why the grant scheme of ECO came about and then evolved into the latest version, ECO 4.
As a Benchmark the Department of Energy believes that homes become efficient once they have achieved a C rating on the Energy Performance Certificates (although there is always room for improvement)

The Government has already bound Landlords to minimum energy efficient standards (MEES) for rental properties. The current MEES standard to be able to rent out a property is an E rating on the EPC expecting to rise to a C rating by 2030.
Buy to let landlords & Homeowners also get a significant mortgage rate reduction on properties they have mortgaged that have a C rating on the EPC.
The grants are designed to help landlords, homeowners & tenants achieve C ratings on their EPC’s via the ECO 4 Fully Grant Funded Framework.
This helps the Government achieve its target ambitions, relieves landlords and homeowners of high costs associated with regulatory controls such as MEES and helps them get lower mortgage rates for the properties they purchase.
Fundamentally, the comfort of the property is greatly enhanced in the process along with the value, for tenants and or homeowners.
(You do not need an existing epc to access the ECO 4 funding)