Electric storage heaters and Electric Heating Systems were classed as renewable heating systems under the first ECO4 legislative amendments, which applied to measures installed from 14 August 2023, according to Ofgem's summary of updates to the ECO4 delivery guidance and measures table1. The classification applies where the products are installed in a home which has solar PV, or which receives solar PV as part of the same project1.
The change came through part 10 of The Electricity and Gas (Energy Company Obligation) Order 2023, which applies to measures installed from 14 August 20232. Ofgem's summary states the position as follows:
"Under the first ECO4 legislative amendments on 14 August 2023, electric storage heaters and Electric Heating Systems are classed as renewable heating systems when installed in a home which has solar PV or receives solar PV as part of the same project."
The same summary records that version 2.1 of the delivery guidance, published 5 April 2024, added information and clarity on the definition of electric storage heaters and Electric Heating Systems and the circumstances in which they can be installed2. That version also added a row to the measures table to differentiate guidance on ESH upgrades to a high heat retention electric storage heater in homes with and without solar PV2.
Later versions of the guidance set conditions on solar PV itself. Version 3.0, published 7 August 2025, added a requirement that some electricity generated must be used in the heat of the domestic premises, alongside requirements and eligibility rules for solar PV and provisions on battery storage installations1. The same version addressed the installation of solar PV where a pre-existing solar PV system is already present1.
The guidance has been revised repeatedly since. Version 3.2 was published 8 December 2025, version 3.1 on 10 October 2025, and version 3.0 on 7 August 20251. Version 4.0, published 26 March 2026, reflects the extension of ECO4 by nine months to 31 December 20261. The same version records that the Great British Insulation Scheme closed on 31 March 20261.
Why it matters for households
The classification matters because it determines whether an electric storage heater or Electric Heating System can be installed as a renewable heating measure under ECO4, rather than being treated as a conventional electric heating upgrade. For a household, that affects whether the product is available through the scheme at all, and it ties the heating measure to solar PV: either the home already has panels, or panels are installed as part of the same project1.
That link has a direct bearing on a home's energy independence. A storage heater charged on off-peak electricity and a solar array that supplies some of the home's electricity are two separate routes to using less imported energy, and the guidance treats them as connected for ECO4 purposes. Households without solar PV, and projects that do not include it, fall outside the classification as described1.
The guidance does not set out rates, grant amounts or eligibility by benefit for these measures in the passages summarised, and no figures for household savings from the classification have been reported1. Eligibility for ECO4 more broadly continues to rest on the scheme's own rules, which the guidance has changed several times, including the removal of Working Tax Credit and Child Tax Credit as evidence after they ceased to exist on 5 April 20251.
What happens next
Version 4.0 of the delivery guidance, published 26 March 2026, reflects the extension of ECO4 to 31 December 20261. The summary also records that the deadline for applications for Innovation Measures is confirmed in a new paragraph 6.1601. No further amendment to the renewable classification of electric storage heaters or Electric Heating Systems has been reported1.