The Energy Company Obligation (ECO4) is a government energy-efficiency scheme in Great Britain, designed to tackle fuel poverty and help reduce carbon emissions. 

ECO4 focusses on improving the least energy efficient homes and households in fuel poverty, as only properties in EPC bands D-G can be treated. It also aims to deliver a more complete upgrade of those homes, shifting to a multi-measure whole-house retrofit approach. Furthermore, a minimum number of private tenure homes in energy efficiency rating band E, F and G must be upgraded throughout ECO4, ensuring the least efficient homes are treated.

Through ECO funding, homes can recieve insulation, heating and solar panels - free of charge!