Definition: ECO4 was the fourth Energy Company Obligation, funding free energy-efficiency upgrades for low-income UK households. It closed to new applications in March 2026.

What it covered

Insulation, heat pumps, solar and boiler replacements, fully funded by energy suppliers for households on qualifying benefits or referred via ECO4 Flex. Approved installations continue to December 2026.

What replaced it

The Warm Homes: Local Grant now covers free upgrades for homes rated EPC D-G with household income under £36,000 — up to £30,000 per home, open until March 2028.

Estimate your numbers: try the free savings calculator or browse all upgrade guides.