Can You Downgrade From a Half-Hourly to Non-Half-Hourly Meter?
With TNUoS charges rising and network costs hitting Half-Hourly meters harder, many businesses are asking if they can switch back to simpler Non-Half-Hourly metering. Most suppliers will tell you it's impossible — but there is a legitimate pathway through something called Change of Measurement Class (CoMC).
While CoMC isn't suitable for everyone, businesses that qualify can potentially save thousands by escaping Half-Hourly charges entirely. Even if CoMC isn't viable, there are proven ways to significantly reduce your HH meter costs through capacity optimisation.
๐ What Is Change of Measurement Class (CoMC)?
Change of Measurement Class is an official process that allows businesses to move from Half-Hourly settlement back to Non-Half-Hourly billing. While most suppliers discourage it, the regulations do permit CoMC under specific circumstances.
The Legal Framework
UK regulations require Half-Hourly metering for businesses with peak demand over 100kW. However, the 70-100kW range is optional. If your peak demand has genuinely fallen below 70kW for a sustained period, you may qualify for downgrade to Non-Half-Hourly settlement.
โ Mandatory HH
Peak demand >100kW
โ๏ธ Optional Zone
70-100kW (CoMC possible)
Why Suppliers Don't Promote CoMC
Most suppliers have blanket "no downgrade" policies because Ofgem is pushing towards Market-Wide Half-Hourly Settlement by 2027. Additionally, HH customers are often more profitable due to higher standing charges and additional service fees.
โก Why Half-Hourly (HH) Settlement Exists
Since the 2017 P272 regulation, Ofgem has required certain larger business electricity supplies to be settled half-hourly — meaning your consumption is recorded every 30 minutes and sent automatically for billing.
TNUoS Cost Increases Coming
With TNUoS (Transmission Network Use of System) charges set to rise significantly in April 2026, businesses with Half-Hourly meters are feeling the pinch. These network charges, which fund the high-voltage transmission system, hit HH supplies with higher standing charges that many businesses are now questioning.
๐ The Two Common Types of HH Meter
Even though both are classed as HH meters, there are two distinct types with different cost implications:
๐ Whole-Current (WC) HH Meter
- Fuse limit: Up to ~100 A per phase (~69 kVA total)
- Installation: No external current transformers
- Appearance: Similar to a smart meter
- Suited to: Small-to-medium businesses with modest energy demand
- Cost impact: Lower additional charges
โ๏ธ Current-Transformer (CT) HH Meter
- Application: For supplies over 100 A per phase
- Technology: Uses external CTs to measure current and a ratio (e.g. 200/5 A)
- Installation: Separate meter cabinet or CT chamber
- Capacity: Can support loads in the hundreds of kVA
- Cost impact: Higher compliance, capacity, and maintenance charges
๐ท The Other Costs Beyond Standing Charges
When you have a Half-Hourly meter, the daily standing charge is only one part of the picture. Most businesses also pay extra fees:
Typical HH Meter Additional Charges
Some of these are unavoidable, but kVA charges are one of the biggest areas where savings can be made.
๐ Understanding kVA Charges — and Why They Matter
Your electricity supply comes with an Agreed Supply Capacity (measured in kVA). Think of it like reserving a parking space that's three times bigger than your car.
๐ธ Real Case Study: Taylor Electrical Solutions LTD
We recently helped Taylor Electrical Solutions LTD reduce their contracted capacity from 70 kVA to 25 kVA after reviewing 24 months of data showing their peak demand never exceeded 21 kVA. At 10.73p per kVA per day, this delivered £1,762.40 annual savings — before we even looked at their energy rates and other potential cost reductions.
Typical Capacity Cost Calculation
๐ When You Might Be Overpaying
Scenario 1: You've taken over a site that was once a manufacturing facility. The old tenant needed high capacity for heavy machinery. You're now running a coffee shop — your demand is far lower, but the kVA hasn't been changed.
Scenario 2: You've been in the same site for years. Your operations have scaled down, but your capacity setting hasn't.
In both cases, reviewing and lowering your kVA could save thousands a year.
Are You Paying for More kVA Than You Need?
Our free 15-minute Capacity Review will check your past usage, compare it to your agreed supply, and tell you exactly how much you could save.
๐ Change of Measurement Class (CoMC): The Way Out?
Most suppliers will tell you downgrading from Half-Hourly to Non-Half-Hourly metering is impossible — but there is a legitimate pathway called Change of Measurement Class (CoMC).
What Is CoMC?
Change of Measurement Class is an official process that allows businesses to move from Half-Hourly settlement back to Non-Half-Hourly billing. UK regulations require Half-Hourly metering for businesses with peak demand over 100kW, but the 70-100kW range is optional.
Mandatory HH
>100kW peak
Optional Zone
70-100kW peak
CoMC Possible
<70kW peak
Why Suppliers Say "No"
Most suppliers have blanket "no downgrade" policies because Ofgem is pushing towards Market-Wide Half-Hourly Settlement by 2027. Additionally, HH customers are often more profitable due to higher standing charges and additional service fees.
Could CoMC Work for You?
Answer 3 quick questions to see if you might qualify for a Change of Measurement Class and escape Half-Hourly charges.
Check My Eligibilityโก CoMC Eligibility Check
1. How long have you been at your current premises with the HH meter?
๐ CoMC Detailed Requirements
- Peak demand consistently under 70kW for 12+ months
- Can provide HH data proving low usage
- Business operations have genuinely changed (downsized, different use)
- Supplier willing to process the request (some refuse on policy grounds)
- Peak demand exceeds 100kW (legally required HH)
- Demand frequently spikes above 70kW
- Less than 12 months of consistent low-usage data
- Supplier has blanket "no downgrade" policy
The CoMC Process Challenges
Even with valid grounds, many suppliers refuse CoMC requests due to Ofgem's push towards Market-Wide Half-Hourly Settlement by May 2027. However, if you genuinely qualify and can save significant money, it's worth pursuing.
๐งพ What If You Really Want to Remove Your CT Meter?
If you still want to explore replacing your CT HH meter with a smaller WC smart meter, you'll likely need:
It's not cheap — but in some rare cases (e.g. closing production facilities or sub-letting part of the site), it might be worth it.
We can help you assess the feasibility, risks, and total cost.
๐ What You Should Do Next
Check Your MPAN Number
Look at your electricity bill for your Supply Number (MPAN). If it starts with "00", you have a Half-Hourly meter. If it starts with "05-08", you should have been migrated to HH under P272.
Review Your Maximum Demand Data
Request 12 months of half-hourly data from your supplier. Look for your actual peak demand vs your contracted kVA. Many businesses find they're paying for 2-3x more capacity than they use.
Calculate Your Potential Savings
Multiply your excess kVA by your DNO's capacity rate (typically £1-£2 per kVA per month). A 100 kVA reduction could save £1,200-£2,400 annually.
Contact Your DNO Directly
Only your Distribution Network Operator can change your agreed capacity. Find yours at energynetworks.org and request a capacity review with your usage data as evidence.
Take Control of Your Electricity Costs
Don't keep paying for capacity you don't use. A simple review could save you hundreds — even thousands — each year.
