Replacing a heat meter on a Non-Domestic RHI installation: readings, evidence and Ofgem notifications

October 23 2026 , 4 min reading time

Replacing a heat meter on a Non-Domestic RHI installation should be treated as a reportable compliance event, with Ofgem guidance currently indicating notification within 28 days. This guide explains the evidence you should retain—serial numbers, dated photographs, closing and opening readings, and updated schematics—plus how to choose a suitable replacement meter for your specific accredited setup.

If you replace a heat meter on a Non-Domestic RHI system, you should normally notify Ofgem within 28 days and keep a complete evidence trail so readings remain continuous and auditable. In practice, that means recording the old meter’s closing reading, the new meter’s opening reading, serial numbers, dated photographs and updated schematics, then submitting the change exactly as instructed in current Ofgem guidance.

Non Domestic RHI heat meter replacement Ofgem: when do you need to report?

Under the Non-Domestic RHI rules, metering changes are not a minor admin task. Ofgem’s replacement-meter guidance expects participants to report relevant meter changes, and current instructions indicate a 28-day window from the date of change. The key principle is simple: if the meter used for RHI reporting has been replaced, removed, or materially changed, treat it as a reportable event and check the latest submission method before you send evidence.

Ofgem distinguishes between packaged and unpackaged metering arrangements, so the evidence required can differ by installation type. This is why owners, operators and installers should avoid assumptions and follow the latest published documents:

Even where a replacement seems like a like-for-like swap, reporting is usually the safest route. Late or incomplete reporting can create avoidable compliance queries.

Evidence you should retain before and after replacement

Good evidence is what protects the participant if Ofgem asks for clarification. Build a replacement file that clearly shows the metering chain before and after the change.

Core records to keep

Old meter details: manufacturer, model, serial number, location, and final (closing) reading.
New meter details: manufacturer, model, serial number, installation date, and initial (opening) reading.
Dated photographs: clear images of both serial plates and readable displays.
Schematics: updated plant schematic showing meter position and flow/return context.
Reason for replacement: failure, damage, end-of-life, inaccuracy concern, or other technical cause.
Installer documentation: commissioning/installation records and any handover notes.

Where possible, keep the file in both human-readable format (PDF) and structured data (for example CSV or JSON exports from metering systems) so the record is easy to review later.

How to maintain a continuous meter reading record

The most common issue after a meter swap is a break in continuity. You can reduce that risk with a simple process.

Take and timestamp the old meter’s closing reading immediately before removal.
Photograph the old display and serial number plate.
Install and commission the new meter in the correct orientation and location.
Take and timestamp the new meter’s opening reading at handover.
Photograph the new display and serial number plate.
Update the schematic and internal asset register on the same day.
Submit notification and evidence to Ofgem per current instructions.

This chronology creates a defensible audit trail showing there is no unexplained gap between old and new readings.

Selecting a replacement meter: why one size does not fit all

Replacement meter selection should match the installation design and current RHI scheme requirements. Do not assume that any heat meter can be dropped into an accredited setup. Suitability can depend on the existing pipework arrangement, meter type used in the accredited configuration, data capture method, and what Ofgem expects for your specific metering class.

If you are scoping options, start with specialist ranges and filter by your system requirements. For example, you can browse heat meters at ECOSPARES, review M-Bus heat meter options, or compare ultrasonic heat meter products before final technical checks. For broader compatibility checks and stock planning, see Tisigo .

Always confirm technical fit and compliance before purchase or installation, and keep written justification for the selected replacement.

Notifying Ofgem: practical submission tips

When notifying Ofgem, present evidence as a clear package rather than scattered attachments. A concise covering note should state the installation ID, meter point affected, date of change, reason for replacement, and a list of enclosed files. Label photos and documents consistently (for example, "Old meter serial", "Closing reading", "New meter opening reading", "Updated schematic").

Most delays come from missing links between documents, so make sure each file references the same dates, serial numbers and meter location. If instructions on the portal or guidance have changed, follow the newest process and retain proof of submission.

Summary

For a Non-Domestic RHI meter swap, report promptly (currently within 28 days), document serial numbers and readings at both ends of the change, keep dated photos, update schematics, and preserve a continuous audit trail. Meter choice must be based on your installation and current scheme requirements, not convenience alone. As a practical starting point, review suitable options here: ECOSPARES heat meter collection. If you need help with replacing your heat meter, then speak with TISIGO - they have replaced hundreds of meters for biomass boilers, and Ground source heat pump installations still claiming RHI.