There's a line on your energy bill that tells you whether the consumption figure is based on an actual meter read or an estimate. Most people don't check it. But if that line says "estimated" — and especially if it's been saying "estimated" for several bills in a row — you might be paying for energy you never used.
How estimated reads work
When your energy supplier can't get an actual reading from your meter, they estimate your consumption. This happens when:
- Nobody is available to let the meter reader in
- The meter is in a hard-to-access location
- The meter reader simply doesn't turn up
- The smart meter isn't transmitting data (more common than you'd think)
- The supplier decides to skip a reading cycle to save costs
The estimate is based on your historical consumption patterns. The supplier's system looks at how much you used in the same period last year, adjusts for seasonal variation, and generates a figure.
In theory, estimates should be close to reality. In practice, they often aren't — and the gap gets wider the longer they run.
Why estimates drift
Estimated reads are calculated from old data. If anything about your business has changed since that data was collected, the estimate won't reflect your actual usage.
Your consumption went down. You installed LED lighting, upgraded to more efficient equipment, reduced operating hours, or lost a tenant in a shared building. The estimate is based on your old, higher consumption. You're overpaying.
Your consumption went up. You added new equipment, extended operating hours, opened a new section of the building, or just had an unusually busy period. The estimate is based on your old, lower consumption. You're underpaying — which sounds good until the catch-up bill arrives.
Seasonal patterns changed. Maybe you used to close for two weeks in August but now you don't. Or you've started running air conditioning in summer when you previously didn't. The estimate's seasonal adjustment doesn't capture these changes.
The baseline data was wrong. If the historical data the estimate is based on was itself estimated, the errors compound. An estimate built on an estimate built on an estimate drifts further from reality with each cycle.
The real cost of estimated reads
Overpayment
If the supplier is overestimating your consumption, you're paying more than you owe on every bill. This is the more common scenario because suppliers tend to err on the side of overestimation — it's easier to refund a credit than chase a debt.
A consistent overestimate of 10% on a business spending £1,000 per month on electricity is £1,200 per year in overpayment. You'll eventually get it back when an actual read happens and the account is reconciled. But "eventually" might be months or years away, and in the meantime, your cash flow is taking the hit.
Underpayment and back-billing
If the supplier is underestimating your consumption, the shortfall accumulates. When an actual read finally happens, the bill reconciles — and you get hit with a catch-up charge covering months or years of undercharged consumption.
These back-bills can be enormous. We've seen businesses receive unexpected bills of £5,000-£20,000 when estimated reads are finally reconciled against actuals.
The back-billing rule: Under Ofgem rules, suppliers cannot back-bill domestic customers for consumption more than 12 months old. For business customers, the situation is less clear. Many suppliers apply a 12-month limit voluntarily, but it's not a regulatory requirement for non-domestic accounts. Some suppliers will back-bill for several years if they can justify it.
Budget uncertainty
Even if the estimates are roughly right on average, they create budget uncertainty. Your monthly energy cost isn't based on what you actually used — it's based on what someone guessed you used. That makes it harder to track efficiency improvements, compare costs year-on-year, or catch genuine billing errors (since the baseline is already approximate).
How to check if your bills are estimated
Look at the bill. Most bills indicate whether the read is actual (A), estimated (E), or customer-supplied (C). The label might be in the small print near the meter reading figure.
Check the meter read sequence. Bills show the opening and closing meter reads. If the closing read on one bill matches the opening read on the next, the system is running on actuals. If the numbers don't connect cleanly, estimates are in play.
Ask your supplier. Request a history of actual versus estimated reads for your meter. They should be able to provide this going back at least 12 months.
How to fix estimated reads
Submit your own reads
The simplest fix. Read your meter and submit the reading to your supplier. Most suppliers accept readings online, by phone, or via their app. For electricity, you need the kWh figure from your meter display. For gas, you need the cubic meter figure.
Submit reads at least once a quarter — monthly if you can manage it. This prevents estimates from drifting too far.
Request an actual read
Contact your supplier and request that a meter reader visits your site. You may need to provide access, and there might be a charge for a special reading visit, but it's worth it if estimates have been running for multiple periods.
Get a smart meter installed
A smart meter transmits readings automatically, eliminating the need for manual reads and estimates. Most business electricity meters are now being replaced with smart meters as part of the national rollout — but many sites still have old meters.
Contact your supplier to check your eligibility and request an installation. There's usually no charge for the meter itself, though there may be a waiting list.
Request a reconciliation
If you've been on estimates for multiple periods and you've now submitted or obtained an actual read, ask your supplier to reconcile your account. They should adjust previous bills based on the actual consumption and issue a credit or debit as appropriate.
If the reconciliation shows you've been overpaying, push for a refund rather than a credit on your account — especially if the amount is significant.
What brokers should be doing
If you're managing client bills, estimated reads should be a red flag every time you see one. Two estimated reads in a row is a concern. Three or more is a problem that needs immediate attention.
Automated bill validation catches estimated reads instantly and flags meters where estimates have been running for multiple periods. That's a conversation starter with the client and an opportunity to demonstrate value.
For a full breakdown of billing errors — including estimate-related problems — see common energy billing errors in the UK. And for a step-by-step guide to checking bills, how to validate energy bills covers the complete process.
Don't let estimated reads silently drain your clients' budgets. Try Edge free and flag every estimated read across your portfolio in seconds.