Circuit and asset-level sub-metering with Purely Insights

Purely supplies and installs wireless and clip-on sensors at circuit, sub-circuit and asset level where they are fitted. The readings land in the same Purely Insights account as your half-hourly electricity, gas and water data, so a production line, a chiller or a lighting circuit sits alongside the meter it feeds. Views run from site to building, meter and circuit, and drill down to a single half-hour. Sub-meter data refreshes at the cadence of the device installed.

Installation is not a capital project. Purely supplies, installs and owns the sensors, so there is no kit-rental fee and no minimum portfolio size. Meter-level coverage continues alongside it: half-hourly electricity, gas and water at meter level refreshed roughly every 30 minutes after settlement, non-half-hourly meters through AMR and supplier billing data with a daily AMR refresh, and manual upload as a fallback where no data flow exists.

A supply meter gives one number per half-hour for everything behind it. That is enough to see that overnight consumption is high, and not enough to say which asset is causing it. Sub-metering splits the same half-hour across circuits, so an always-on plant item can be separated from process load and from lighting. Purely Insights then applies the same anomaly detection to sub-meters as to meters: weekend usage, overnight spikes, missing reads and holiday baselines, with configurable thresholds per meter and sub-meter in kWh, kW, £ or kgCO2e.

One published anonymised example: a food and drink manufacturer, single site, 12 GWh, put sub-metering on three production lines. The circuit traces isolated a refrigeration setpoint drift, it was fixed in one shift, and baseload came down 11 percent year on year. As an industry-typical guide, baseload usually runs at 15 to 25 percent of total kWh on offices and schools, and anything above 35 percent normally points to a BMS schedule or an always-on plant fault. Those ranges are industry norms, not Purely measurements.

The sensors sit on Purely's balance sheet. The data sits on yours. There is no lease to sign and no capex to approve, and if you leave, the sensors are returned at no notice cost. Sub-metering is part of Purely Insights, included free with every Purely Energy supply contract: no per-meter fee, no kit-rental fee, no minimum portfolio size and no hidden uplift on the unit rate. There is never a separate Insights invoice, only one supplier invoice per fuel per meter each month, plus a free reconciliation pack.

The platform is funded by a disclosed broker margin on supply, 0.3p to 1.0p per kWh depending on volume and term, shown line-by-line on every quote and renewal. For context, standalone third-party monitoring typically costs £15 to £80 per meter per month. On exit you keep all consumption data, including sub-meter traces, exportable as CSV, JSON or Excel for the life of the account plus 12 months. The dashboard goes read-only at the end of supply.

Every sub-meter can carry its own thresholds, so a chiller circuit and an office lighting circuit are judged on different numbers. Alerts go out by email, SMS or webhook, as a daily digest or in real time, with escalation routing to the recipients you nominate. Aggregations run hourly, daily, weekly, monthly and annual, weather-adjusted using heating and cooling degree days so a cold February compares fairly with a mild one. Role-based access, an audit trail and unlimited users mean site engineers and finance see the same figures.

Circuit-level data also strengthens reporting. Scope 1 gas and Scope 2 electricity emissions use DEFRA's latest published carbon factors, refreshed annually, and sub-meter traces can be attributed to the assets that produced them. Exports come as CSV, Excel, PDF and board-pack PDF, with a read-only JSON API on request for finance, BI, ESG and BMS systems. Compliance packs cover SECR, ESOS Phase 4, ISO 50001 evidence and CDP.