Half-hourly meters for business: who needs one and what it means

A half-hourly (HH) meter records how much electricity you use in every 30-minute slot, 48 readings a day and 17,520 a year (365 × 48). Ordinary meters just add up total use, and the bill is built from occasional readings. HH metering is mandatory for larger sites and is spreading to everyone as part of a national settlement reform.

Who must have a half-hourly meter

Electricity users are placed in one of eight profile classes, shown as the first two digits of the top line of the MPAN. Classes 1 and 2 are domestic. Classes 3 and 4 are ordinary non-domestic supplies (unrestricted and two-rate). Classes 5 to 8 are maximum-demand customers, the larger sites, split by how steadily they use power.

Under Balancing and Settlement Code change P272, which Ofgem approved on 29 October 2014, profile class 5 to 8 sites are settled on their actual half-hourly data. Elexon, which runs the settlement system, says this took effect in April 2017. In practice if your site is in classes 5 to 8, you already have, or must have, an HH-capable meter. Smaller sites in classes 3 and 4 are not required to have one. They are being moved to half-hourly settlement under MHHS (see below), which usually uses data from a smart meter rather than a dedicated HH meter.

Some sites are in profile class 00, which means half-hourly settled. One broker guide notes these now include some smaller sites, so a 00 does not always mean a big factory.

How it differs from a standard meter

	Standard (non-half-hourly)	Half-hourly
What is recorded	Total kWh, sometimes day and night registers	kWh in each 30 minutes, plus maximum demand
How the market treats you	Your annual total is spread using a typical profile for your class	Your own pattern is used
Extra bill lines	Few	Often capacity, excess capacity and reactive power charges
Meter contracts	Usually bundled by the supplier	Operator and data agents are appointed, sometimes separately

Elexon explains that where a site is not half-hourly settled, the market estimates its half-hourly use by applying a class profile to its annual figure. HH settlement replaces that guess with measured data.

Why your bill may look different

Sites on HH meters are typically billed with more separate lines. You may see charges that depend on how much power you can draw at once, measured in kVA, rather than just kWh. Our guide to supply capacity and kVA charges explains how to avoid paying for capacity you do not need. Wider network costs such as DUoS are often charged by time of day on HH meters, so use in peak periods can cost more.

Costs and who you pay

We could not verify typical prices for HH meters or operator contracts, so ask for a written breakdown. What is known: a meter operator (MOP) must be appointed for an HH meter, and the standard operator contract commonly runs five years and may auto-renew unless you give notice, according to a broker guide. The operator maintains the meter at least every five years. When the operator is bundled, the cost sits inside your standing charge. When it is standalone, it continues if you switch supplier. See meter installation and replacement for the roles.

If you are quoted a surprisingly low standing charge, check whether metering and data collection are excluded and billed separately.

The link to market-wide half-hourly settlement

The government and Ofgem are moving the whole electricity market to half-hourly settlement, called MHHS. Elexon reports that suppliers began migrating meters on 22 October 2025, that around 80% of meters were expected to be migrated by October 2026, and that full implementation is due in May 2027. As of its June 2026 update, more than 11.3 million migrations were done, about a third of Britain's metering systems. Read our MHHS guide for what this means in practice.

The key point for you: being settled half-hourly is not the same as having a half-hourly meter physically fitted. Smart meters can supply the data, which is one reason business smart meters matter.

A worked example

A workshop uses 120,000 kWh a year and its highest demand is 60 kW. If it ran at 60 kW all year it would use 60 × 8,760 hours = 525,600 kWh. Its actual use is 120,000 ÷ 525,600 = 22.8% of that, called a load factor. A load factor of 20% to 30% puts it in profile class 6 (Elexon's bands). Because it is class 6, it needs an HH-capable meter and is settled on actual half-hourly figures, so if it moves heavy machinery use from 5pm to 10am it can lower the share of peak-time charges it pays.

What you can do with the data

• Spot night-time or weekend baseload from equipment left on.
• Find the half-hours that set your maximum demand.
• Check your agreed capacity is neither too high (wasted) nor too low (excess charges).
• Send accurate data when you request quotes.

Ask your supplier or meter operator for access; suppliers must give non-domestic customers up to 12 months of historic smart or advanced meter data free on request, according to the government's summary of supplier obligations.

Common mix-ups

"Half-hourly" is not the same as "smart"

A smart meter (see the SMETS2 glossary entry) is a particular type of device that talks to a national network. A half-hourly meter is defined by what it records. Many modern smart meters can do both, but an older HH meter in a big building may be neither smart nor SMETS2.

Your supplier may not be your meter operator

If a meter fault or access issue arises, the person to call may be the operator, not the supplier. Your supplier should tell you who they have appointed. If you are mid-dispute about a reading, see disputing a high bill.

Switching supplier does not usually mean a new meter

The meter stays where it is; the supplier on the record changes. A standalone operator agreement carries on, but a bundled one is replaced by the new supplier's arrangements. Check this before you switch.

Estimated bills should be rarer

With readings arriving automatically, the data should come in without you submitting anything. If you still receive estimates, ask why; see estimated business energy bills.

Next steps

1. Find your MPAN and read the first two digits.
2. If it starts 05 to 08 or 00, check who your meter operator is and when the agreement ends.
3. Ask for your maximum demand and agreed capacity figures.
4. If you are in class 3 or 4, ask your supplier when your meter will move to half-hourly settlement and whether it needs a smart meter to do so.