Heat network reporting deadlines

Dates from Ofgem's regular data reporting guidance (10 March 2026). Verified 15 September 2026 against the guidance PDF, Tables 1 and 2 and paragraphs 2.3–2.7.

Quarterly windows

Data is a snapshot on the last day of the quarter unless the data point says otherwise. You can submit from the first day of the following month until its last day.

Annual return

Covers 1 April to 31 March. Submitted 1–30 April with the Q4 return (Table 2). Financial resilience data (Table 3) is the exception: it is due in the quarter your accounts are signed off, and no later than 10 months after your financial year end (para 2.6).

Extensions

If you cannot submit by the deadline, you can ask Ofgem for an extension to the last calendar day of the following month (para 2.5). Do not rely on this by default.

Backdating for 2026

Ofgem asks networks to collect data from April 2026 and submit what they have once registered. It will accept the data available for April–June 2026 (paras 2.14–2.15). The digital service is expected to accept data submissions from autumn 2026; Ofgem will issue a Request for Information before the first window. Verified against Ofgem, How to prepare for data reporting (9 April 2026).

Upcoming windows

• Q2 2026/27: submit 1 October 2026 – 31 October 2026
• Q3 2026/27: submit 1 January 2027 – 31 January 2027
• Q4 2027/27: submit 1 April 2027 – 30 April 2027, plus the annual return
• Q1 2027/28: submit 1 July 2027 – 31 July 2027
• Q2 2027/28: submit 1 October 2027 – 31 October 2027
• Q3 2027/28: submit 1 January 2028 – 31 January 2028