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Non-half-hourly

What is non-half-hourly (NHH) metering?

Most UK business electricity meters live in a quiet middle ground called non-half-hourly settlement. For everything from a tiny shop with a single till to a mid-size warehouse running standard hours, NHH is the default. The meter records cumulative kWh. The supplier estimates the half-by-half pattern using a standard consumption profile for sites of your type, then bills the actual reading when it eventually arrives. NHH covers the vast majority of UK business sites below 100 kW maximum demand. It is also currently being reshaped by the Market-wide Half-Hourly Settlement (MHHS) programme, which moves all sites to HH settlement by 2026 without necessarily changing the bills the customer sees.

NHH is the default settlement basis for smaller business electricity supplies. Most UK businesses are on it without ever needing to think about it.

NHH and HH are the two settlement worlds in UK business electricity. Bigger sites are mandated onto HH. Most others sit on NHH. The Market-wide Half-Hourly Settlement (MHHS) programme is currently rolling out HH to NHH sites by 2026, which will change the settlement basis for almost every UK electricity supply without necessarily changing the bill format the customer sees.

What NHH metering actually does

NHH meters record total electricity consumption over a billing period.

• The meter shows cumulative kWh on a single register (or two registers for Economy 7).
• A meter reader visits periodically, or the customer submits readings, or a smart meter sends them automatically.
• Between actuals, the supplier estimates consumption using a profile class that approximates how sites of that type typically consume across the day, week, and year.
• The bill is built from a mix of actuals and profile-based estimates.

It is a simpler system than HH metering, which records and bills the actual kWh for each individual half-hour.

When a site is on NHH

NHH is mandatory below a defined consumption threshold.

• Maximum demand below 100 kW (rough equivalent of below 100,000 kWh per year).
• No request from the customer or supplier to move to HH voluntarily.
• Standard for the vast majority of UK small and mid-size business electricity supplies.

Sites above the threshold are required to use HH. Sites below can also voluntarily move to HH for access to time-of-use tariffs, pass-through contracts, or flexibility revenue.

How NHH data flows

1. The meter records cumulative kWh on its display.
2. A reading is collected by meter reader visit, customer submission, or smart-meter automatic transmission.
3. The reading goes to the supplier through industry data systems.
4. The supplier calculates consumption since the last reading.
5. For the period between actual readings, the supplier estimates consumption using the site’s assigned profile class.
6. The bill applies the unit rate to the calculated kWh and presents the result.

If actual readings are infrequent, the bill leans heavily on estimates. See estimated read for the mechanics.

Profile class and AAHEDC factors

Every UK NHH site is assigned a profile class (PC) which describes its expected consumption pattern. Six standard NHH profile classes.

• PC 01. Domestic unrestricted.
• PC 02. Domestic Economy 7.
• PC 03. Non-domestic unrestricted.
• PC 04. Non-domestic Economy 7.
• PC 05. Non-domestic 0-20 per cent load factor.
• PC 06. Non-domestic 20-30 per cent load factor.

The profile decides how supplier estimates between actual reads are distributed across the year. It also feeds into settlement and certain non-commodity charges. AAHEDC (Assistance for Areas with High Electricity Distribution Costs) charges apply differently across profile classes too.

How NHH affects the bill

NHH bills are simpler than HH bills.

• Unit rate. Flat per-kWh rate for all consumption (or two-register day/night rate on Economy 7).
• Standing charge. Fixed daily amount.
• CCL. kWh times CCL rate.
• VAT. 5 or 20 per cent depending on supply type.
• Capacity charges. Not itemised. Bundled into the standing charge.
• DUoS, TNUoS, BSUoS. Bundled into the unit rate as part of the supplier’s all-in price.

The bundling makes NHH bills easier to scan but harder to dissect for cost optimisation.

NHH vs HH metering

Market-wide Half-Hourly Settlement (MHHS)

MHHS is the UK industry programme moving all electricity supplies to half-hourly settlement by 2026.

• The programme rolls out in tranches starting with larger non-domestic and progressing to smaller non-domestic and domestic.
• Customer-facing bills can stay in similar formats; the change is mostly in how suppliers reconcile costs.
• For most NHH sites, the operational impact will be invisible.
• For sites that want to access time-of-use tariffs, MHHS opens the door without needing a voluntary HH move.

See half-hourly meter for the HH side.

Switching supplier on NHH

NHH switching is faster than HH because there are fewer industry data flows to update.

• Typical time. 4 to 6 weeks from accepting a new contract to going live.
• Required information. MPAN, current supplier, recent meter reading.
• No MOP or DC/DA contracts to migrate.
• The Change of Supplier is processed centrally and the new supplier picks up from the agreed date.

Limits of NHH for growing sites

NHH starts to feel constraining when the site outgrows its profile class.

• Site expands, new equipment, or extended operating hours. Consumption pattern shifts away from the profile.
• The supplier’s estimates between actual reads drift further from reality.
• Bills become less predictable.
• If maximum demand approaches the 100 kW threshold, an HH move may be triggered automatically or by the supplier.

For sites approaching 80,000-90,000 kWh per year on consistent growth, planning the HH transition before the threshold is crossed avoids a forced migration on short notice.

Practical implications for businesses

For most UK NHH customers, the settlement category is invisible. Two situations where it matters.

• Reviewing your profile class. If consumption patterns have changed materially, requesting a profile class review can produce more accurate estimates and bill predictability.
• Considering a voluntary HH move. Sites below the threshold can still benefit from HH where time-of-use load shifting, pass-through contracts, or flexibility revenue is on the table.

Related entries. half-hourly meter, profile class, MPAN, estimated read, Economy 7, smart meter, bill validation.

AAHEDC and other regional adders

Beyond the headline unit rate and standing charge, UK NHH bills carry a handful of smaller regional adders that depend on profile class and supply region.

• AAHEDC (Assistance for Areas with High Electricity Distribution Costs). A redistribution charge that subsidises distribution costs in higher-cost regions (notably North Scotland) and is recovered from customers in lower-cost regions.
• Distribution charges (DUoS). Bundled into the unit rate on NHH bills but vary by region and profile class.
• Transmission Network Use of System (TNUoS). Recovered through the unit rate, varies by region.

For small NHH customers these are invisible bundled costs. For larger NHH customers (close to the HH threshold) the differences between regions can be material when comparing offers from regionally-focused suppliers.

Common NHH pitfalls

Recurring issues that catch UK NHH customers off guard.

• Drifting estimates. Long gaps without an actual meter reading produce estimates that diverge from real consumption. Submit a reading once a month to keep the bill honest.
• Wrong profile class. Consumption pattern changes (new equipment, new operating hours) without a profile class review produce inaccurate estimates and possibly miscalculated network charges. See profile class.
• Hitting the HH threshold. Growing sites that pass 100 kW maximum demand are forced onto HH without warning. Planning the transition before the threshold is crossed avoids reactive moves.
• Smart meter still in NHH mode. SMETS2 meters can run in HH mode but are often left in NHH after install. A request to the supplier can convert without hardware change.

Frequently asked questions