Ofgem heat network quarterly reporting: what small networks must submit

Last checked against Ofgem's published guidance on 15 September 2026. Not legal advice; see disclaimer and sources.

Since 27 January 2026, Ofgem regulates heat networks in Great Britain, including communal heating in blocks of flats. Anyone authorised as a heat network supplier or operator has to give Ofgem regular data about the network under authorisation condition A09, “Provision of Information to the Authority”. Verified: Ofgem regular data reporting guidance, para 1.10.

This guide covers what that means in practice for a small private network: one block, one plant room, a landlord or managing agent recovering the cost from residents.

Two rhythms: quarterly and annual

Ofgem’s guidance (10 March 2026) sets out six tables of data points. Some are quarterly, some annual. The annual ones are submitted in the same window as the Q4 return.

Verified: guidance Tables 1 and 2. An extension to the last day of the following month can be requested (para 2.5). Organisation-level financial data is the exception: it’s due in the quarter your accounts are signed off, within 10 months of year end (para 2.6).

Each figure is a snapshot on the last day of the period unless the data point says otherwise (para 2.2).

What’s in a quarterly return

For a typical private residential block where the same organisation is supplier and operator, the quarterly return has 18 data points across three areas:

Vulnerability and debt (Table 6) — domestic customers who have met the debt trigger (over £200 outstanding for three months or more after the bill date, and not on a repayment plan), self-disconnections, disconnections for non-payment, customers on repayment plans, reconnections, and meters involuntarily switched to prepayment.

Quality of service (Table 7) — complaints received, split into six categories (back billing, quality of service, customer service, vulnerability/debt/switching, pricing, other), how many were group complaints, how many were referred to the Energy Ombudsman, how many were resolved by the end of the next working day, and how many between then and eight weeks.

Pricing (Table 8) — every standing charge (pence per day), every unit rate (pence per kWh), flat fees (£ per day), connection charges received, other one-off charges, and total charges billed to domestic and to non-domestic customers.

Verified: guidance Tables 6–8, pages 18–23.

What’s in the annual return

Another 31 data points for that same block: customer and meter counts (Table 4), billing frequency and payment methods (Table 5), the Priority Services Register count and bad debt (Table 6), and the annual pricing items (Table 8): what a 6,000 kWh reference customer pays, your pricing method, which costs each charge recovers, fuel type, cost of heat, kWh generated and delivered, revenue and running costs. Plus eight organisation-level finance questions (Table 3) if you are not a council or registered social housing provider.

Who reports what

• Some data points are required from the supplier, some from the operator, some from both. If one organisation holds both roles, it reports everything once.
• Self-supply networks are exempt from all six tables. Industrial networks only provide Table 4. Verified: exemption columns in Tables 3–8.
• Local authorities and registered social housing providers skip Table 3. Verified: Table 3.
• Networks that supply only non-domestic, micro-business or small business customers skip Tables 5 and 6 and the reference-usage price. Verified: Tables 5, 6, 8.

Heat in the service charge still counts

If heat is included in rent or the service charge, Ofgem calls it a “bundled” charge. You still report the customer, debt and pricing data, using the heat element of the charge. Standing charges and flat fees inside a service charge are reported as the heat network element only. Verified: paras 2.21–2.22, Tables 6 and 8. See our guide on service charges.

When it starts

Ofgem asks networks to collect data from April 2026. Existing networks can register any time up to 26 January 2027, then submit what they have recorded since April, and Ofgem will accept the data available for April–June 2026. The digital service is expected to accept submissions from autumn 2026; Ofgem will send a Request for Information before the first window. Verified: paras 2.14–2.15 and How to prepare for data reporting.

What to do this month

1. Start a complaints log with type, date received, date resolved and any Ombudsman referral.
2. Start a debt log: who is over £200 and for how long, repayment plans, any disconnections.
3. Write down your tariff, or if heat is in the service charge, how the heat element is worked out.
4. Find the annual figures: fuel bills, heat meter totals, heat revenue, running costs.
5. Register on Ofgem’s digital service and join the Energy Ombudsman scheme if you haven’t.

Knowingly or recklessly submitting false or misleading data is prohibited under regulation 62 of the Regulations; if you spot an error after submitting, raise it with Ofgem. Verified: para 2.20.