Half-hourly meters are the gold standard for business electricity metering in the UK. They record your usage every 30 minutes, send data daily, and unlock cheaper, more accurate tariffs. This guide explains who needs an HH meter, who should opt-in voluntarily, and how the move from profile-class to half-hourly settlement affects your bill.
What is a half-hourly meter?
A half-hourly meter is an advanced electricity meter that records cumulative kWh consumption every 30 minutes (48 readings per day, 17,520 per year) and transmits the data via GSM or fixed line to a Data Aggregator and your supplier. Suppliers settle the wholesale market in 30-minute periods, so HH metering lets your supplier price your supply at the actual market rate for each half-hour rather than an assumed profile.
Who needs a half-hourly meter?
HH metering is mandatory in two cases:
- Maximum demand over 100 kW: Any UK business whose peak demand crosses 100 kW (kilowatts) at any point in the year is automatically rolled to HH settlement (Profile Class 00) by the central code rules.
- Profile Class 5-8 from April 2017 onwards: All new advanced and smart meters in the PC 5-8 segment have been mandated to settle on a half-hourly basis under the P272 / P376 changes.
Below 100 kW peak demand, you can opt-in voluntarily by installing an HH-capable meter (most modern smart meters are HH-capable).
How is HH electricity priced?
HH-settled supply is priced as:
- Wholesale element: based on actual half-hourly system price.
- Network charges: TNUoS by triad demand (the three highest half-hours of the year for transmission) and DUoS by HH band (red, amber, green).
- Other non-commodity: similar to profile-class but charged per HH.
The result is a tariff with a unit rate that varies by time of day and season — typically a “red band” rate (4-7pm winter weekdays) several times the “green band” rate (overnight and weekends). Smart users shift load away from red bands to cut bills.
Profile class vs half-hourly: the bill impact
For a 200,000 kWh/year business with peaky daytime usage, moving from profile class 8 to HH typically reduces the unit rate by 2-4p/kWh because the supplier can see the real load shape rather than assuming a worst-case profile. The exact saving depends on your load shape; flat 24/7 users save less, peaky daytime users save more.
Should you opt-in to HH below 100 kW?
Worth considering if:
- Your peak demand is approaching 100 kW (you will be forced to HH soon anyway).
- You have a smart meter installed already (no installation cost).
- Your usage is concentrated in off-peak hours (you will benefit from low green-band prices).
- You can shift load away from red bands (manufacturing, cold storage, EV charging).
Probably not worth it if:
- Your usage is small (under 50,000 kWh/year) — admin overhead outweighs unit rate savings.
- Your load is flat or office-hours only with no shifting flexibility.
How to install or upgrade to a half-hourly meter
Speak to your current supplier about installing or unlocking HH on your meter. The process takes 4-12 weeks depending on whether new physical metering is needed or just a settlement-class change. There is usually a one-off install fee (£200-1,000) and an annual standing data charge (£100-300/year). Most businesses recoup the cost in year one.
Frequently Asked Questions
Non-half-hourly meters record only cumulative usage and are billed against an assumed consumption profile. Half-hourly meters record actual usage every 30 minutes, allowing suppliers to bill against real wholesale and network prices for each period.
Most modern UK smart meters are HH-capable but are not always settled on a half-hourly basis. A smart meter records HH data; whether your supplier uses that for settlement depends on whether your meter is registered as Profile Class 00 (HH) or 1-8 (NHH).
One-off install of CT-metered HH equipment costs around £200-1,000 depending on site complexity. Annual data charges are typically £100-300. Most businesses recoup the cost in unit rate savings within 12 months.
Yes, if your maximum demand exceeds 100 kW, or if you have a profile class 5-8 advanced meter under P272/P376 rules. Otherwise it is optional.
Transmission charges (TNUoS) are billed against your demand during the three highest half-hour system peaks of the year (the “triads”). Reducing your demand in those windows — usually 4-7pm on cold winter weekdays — can save thousands per year for large HH-settled users. Many businesses use a triad-warning service.
Want to know if HH settlement would save you money? Get a free 60-second quote for both NHH and HH options for your meter, or call 0333 015 2615 for a personalised review.
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