Can a supplier change my price during a fixed term?
Usually the energy part of a fixed-term price stays fixed, but some charges, such as environmental levies, may be passed through and change during the contract. Your Principal Terms should say which parts of your price can vary, so check them.
Fixed doesn't always mean fixed
Ofgem's guidance warns that some business contracts pass through changing charges, such as environmental tariffs, once the supplier knows the amounts. Its advice is to check whether your price can vary during the term. So the answer depends on how your contract is built.
What can change, and what shouldn't
| Part of your price | Fixed contract | Pass-through contract |
|---|---|---|
| Energy (wholesale) element | Fixed | Fixed |
| Network and levy costs | Included in your rate | Billed at actual cost |
| Standing charge | Per contract terms | Per contract terms, possibly with pass-through of some elements |
The difference is explained in pass-through vs fixed charges in a quote.
A worked example
A salon on a pass-through contract uses 12,000 kWh a year. If the passed-through costs rise by 1.5p/kWh, the annual bill rises by 12,000 × £0.015 = £180, without any change to the headline unit rate. On a fully fixed contract the same rise would be the supplier's problem.
Other price changes to watch for
- End of term: a new price applies when your fixed term ends. See why prices go up at renewal.
- Deemed or out-of-contract: these rates can change more often. See moving premises and deemed contracts.
- Tax changes: VAT and Climate Change Levy are charged on top and follow government rates; the CCL main rate is 0.801p/kWh from 1 April 2026 and 0.827p/kWh from 1 April 2027. See VAT and Climate Change Levy.
If you think your price was changed wrongly
- Compare your bill with the Principal Terms and contract.
- Ask the supplier to explain the change in writing.
- Complain formally if the explanation doesn't match the contract.
- Microbusinesses and small businesses can go to the Energy Ombudsman after 8 weeks or with a deadlock letter.
Check these four documents
- The contract and Principal Terms: which charges are fixed or passed through.
- The supplier's general terms and conditions.
- Any notice of change you were sent.
- Your bills, line by line.
If you cannot match the bill to the terms, the issue is worth raising as a billing dispute; see disputing a high business energy bill.
A note on standing charges
Many owners focus on the unit rate and overlook the daily standing charge. Whether it can change mid-term depends on your contract, so check whether it is fixed for the whole term. A small daily rise adds up: an extra 5p a day is 5p × 365 = £18.25 a year per meter, which is modest, but a bigger rise across several sites is worth querying.
What if the supplier wants to change your contract terms
If you receive a letter proposing different terms mid-contract, do not ignore it. Read what changes, when, and whether you have a right to leave. Whether the supplier can make the change depends on the wording of your contract, so ask it to point to the clause that allows it, and keep the reply. If you are unsure, get independent advice before you accept.
Next steps
Ask which charges can vary before you sign; use the contract checklist.
Sources
General information only. Energy prices, rules and supplier terms change; check the latest position with your supplier, Ofgem or the Energy Ombudsman before you act.