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Energy Company Obligation 3 interim measures

The Energy Company Obligation (ECO) 4 order commenced on 27 July 2022 and will run to 31 March 2026. Measures delivered between 1 April 2022 to 26 July 2022 will contribute to ECO 4 delivery and will be known as ECO 3 Interim measures as they are delivered in accordance with ECO 3 regulations.

Suppliers had to notify us of any ECO 3 interim measures installed between 1 April 2022 and 26 July 2022 by the end of September 2022.

Any ECO 4 measures completed between 27 July 2022 and 31 July 2022 also had to be notified by the end of September 2022.

Any measures completed on or after 1 August 2022 must be notified by the end of the month following the month in which installation of a measure was completed.

Progress towards Phase 1, 2, 3 and 4

To achieve its ECO obligations, a supplier must install measures that qualify under the scheme and deliver annual bill savings for the household.

ECO4 sets a main obligation called the Home Heating Cost Reduction Obligation (HHCRO), which requires energy suppliers to achieve a total of £224.3 million in annual bill savings for domestic premises by 31 March 2026.

The obligation is divided between energy suppliers based on their respective shares of the domestic gas and electricity market.

A supplier meets its obligations under ECO4 by promoting qualifying actions (‘measures’) at eligible domestic premises, and must do so in full no later than 31 March 2026.
           
The overall obligation period for ECO4 runs from the commencement of the ECO4 Order on 27 July 2022 to 31 March 2026 and is split into four phases:

•    Phase 1: 27 July 2022 to 31 March 2023
•    Phase 2: 1 April 2023 to 31 March 2024
•    Phase 3: 1 April 2024 to 31 March 2025
•    Phase 4: 1 April 2025 to 31 March 2026

A supplier’s total obligation is determined by adding together their obligations for each phase. They must meet their total obligation by the end of 31 March 2026.

Notified ECO 4 measures by category

The table below shows the measures submitted to Ofgem as of 8 September 2025. 

This does not include ECO 4 measures that have been notified as exemption measures. For further details on exemption measures, please refer to our Energy Company Obligation (ECO4) Guidance: Delivery.

Measure Type ECO4 SA ECO3 Interim ECO4 Total
Boiler - Repair of a broken heating system  0  0  0  0 
Boiler - Replacement of a broken efficient heating system  1,847  1,804  367  4,018 
Boiler - Upgrade to a renewable heating system  0  0  28,866  28,866 
Boiler - Upgrade to a non-renewable heating system  4  1  68,820  68,825 
Boiler - Upgrade to Unknown  -  -  3  3 
Cavity Wall Insulation  13,724  12,723  25,680  52,127 
District Heating Connection   0  2  1,316  1,318 
ESH - Repair of a broken efficient electric storage heater with a high heat retention electric storage heater  -  -  0  0 
ESH - Replacement of a broken efficient electric storage heater with a high heat retention electric storage heater  0  0  0  0 
ESH - Upgrade to a high heat retention electric storage heater  1,749  1,724  7,777  11,250 
First time central heating to a non-renewable heating system  2,775  1,802  13,352  17,929 
First time central heating to a renewable heating system  32  72  11,471  11,575 
First time central heating to an unknown heating system*  -  -  1  1 
Heating controls  15,809  5,169  424,136  445,114 
Loft Insulation  11,883  4,039  95,204  111,126 
Other Insulation**  100  35  4,648  4,783 
Park Home Insulation  29  0  973  1,002 
Room-in-roof Insulation  946  290  15,948  17,184 
Solar PV  138  103  52,237  52,478 
Solid Wall Insulation  6,956  1,570  68,060  76,586 
Underfloor Insulation  4,703  896  1,408  7,007 
Total  60,695  30,230  820,267  911,192 

Table commentary

A total of 203,014 Energy Company Obligation 4 projects have been submitted, an increase of 6,367 projects from the previous month.

*A small number of measures have been submitted with an invalid post main heating source for the property, suppliers will be required to update this information

**Other Insulation includes the following measure types – flat and pitched roof insulation, solid floor insulation, window glazing, draught proofing and higher performance external doors. These measures are grouped together given the low delivery volumes.

Percentage of energy company progress towards obligations and cap

Data is accurate as of 8 September 2025.

Notified delivery refers to measures and projects which suppliers have submitted to the Energy Company Obligation 4 register. The notified percentage will count partial project scores from non-approved measures, where the measures and projects are still undergoing their eligibility review.

Approved delivery refers to those that have passed eligibility reviews to count towards the obligation target. The approved percentage will count full project scores from approved projects. Where a project has been completed but yet to be approved, partial project scores from the approved associated measures are used.

Please note that:

  • due to notification and validation errors, there are measures and projects which do not have scores generated, meaning the current progress figures do not reflect 100% of delivery towards ECO4. As of 8 September 2025, the data shows progress for 96.53% of delivery, therefore actual delivery is likely to be higher
  • progress from approved surplus actions carried over from ECO3 is now reflected in the data
  • as of July 2025, ECO3 Int and ECO4 Surplus Action progress will remain static for the next few months whilst some digital improvements are being implemented