How to switch business energy supplier: steps, timings and common snags

The short version

Check your contract end date, get quotes using your meter numbers and usage, choose one, and let the new supplier handle the switch. Your supply is not interrupted. The key rule: do not agree a new contract until you know you are free to leave the old one, because there is no cooling-off period for business energy.

Step by step

1. Find your current contract end date and terms. Ofgem says to check when you can switch, how much notice you must give and whether you will pay an exit fee. See how to find your end date.
2. Work out what type of contract you are on. Fixed, variable, evergreen, out-of-contract or deemed (see below).
3. Gather your details: MPAN and MPRN, annual usage, meter type, company name and address. See find your MPAN and MPRN.
4. Get quotes from your current supplier, from other suppliers direct, and optionally through a comparison site or broker. See business energy comparison.
5. Compare total annual cost, contract length, fees and exit terms.
6. Check any broker fee in the Principal Terms.
7. Agree the contract in writing and keep a copy.
8. Sort any debt with the old supplier.
9. Submit a final meter reading on the switch date. See submit a business meter reading.
10. Check the first bills from the new supplier and confirm the old supplier's final bill.

When can you leave?

Contract type	Can you switch?
Fixed term	Usually at the end. Ofgem says a window opens before the end date when you can renew or tell the supplier you are leaving; your renewal letter gives the exact dates. Leaving earlier may mean an exit fee.
Variable, evergreen, out-of-contract, deemed	Any time, according to Ofgem.

Out of contract, no termination fee can be charged, and microbusinesses cannot be forced to give notice except under an evergreen contract, where up to 30 days can be required. For microbusinesses, a rollover can last no more than 12 months and is only allowed if the supplier sent the required renewal information. See do I need to give notice and rollover contracts.

How long does it take, and will I lose power?

Timing depends on the supplier, meter type and whether the switch hits a problem. Instead of promising a number of days, see how long it takes to switch. Your electricity and gas keep flowing: see will my supply be interrupted.

Worked example: what staying put can cost

A micro site uses 20,000 kWh of electricity a year. A Moneysupermarket Business page dated 21 October 2026 gave average out-of-contract electricity as 40.0p/kWh plus 254.0p/day, against average microbusiness fixed rates of 28.4p/kWh plus 58.0p/day. These are indicative averages.

• Out of contract: (20,000 × 0.40) + (365 × 2.54) = 8,000 + 927.10 = £8,927.10
• Fixed average: (20,000 × 0.284) + (365 × 0.58) = 5,680 + 211.70 = £5,891.70
• Difference: £3,035.40 a year, or about £253 a month.

Try your own figures in the out-of-contract energy cost calculator.

A switching timeline you can copy

Using a fixed contract ending on 31 March as an example, and treating the exact notice dates as whatever your renewal letter says:

When	What to do
As soon as the renewal letter arrives	Note the end date and the last date to give notice that you are leaving or do not want a rollover.
Next few weeks	Gather MPAN, MPRN and 12 months of usage; request at least three quotes for a start date of 1 April.
Before the notice deadline	Give written notice to the current supplier if your contract requires it, and keep proof of sending.
Once you choose	Agree the new contract in writing with a start date after the old term ends; check the broker cost in the Principal Terms.
31 March / 1 April	Take dated photos of each meter and send the reading to both suppliers.
First two bills	Check the opening reading, unit rate and standing charge match the contract.

What not to do while a switch is going through

• Do not cancel your Direct Debit with the old supplier until its final bill is settled.
• Do not agree to a second offer from another caller; two competing contracts can cause a rejected switch and a dispute.
• Do not ignore a letter from your old supplier; if it says it is objecting, find out why straight away.

Common objections and what to do

"My supplier says I owe money"

Ofgem warns that a supplier may object to your switch if you owe it money. Contact it quickly. Often you can clear the balance or agree a payment plan, which lets the switch proceed. If the bill is disputed, raise a formal complaint in writing. See switching when you owe money and disputing a high bill.

"My switch was rejected"

Typical causes are an incorrect meter number, another switch already in progress, debt, or a contract still in its fixed term. See why a switch is rejected.

"I only want to switch gas, or one site"

You can switch fuels separately, and often switch some sites but not others. See switching gas or electricity separately and switching multiple sites.

"My supplier will not let me leave"

If you are in a fixed term, check the termination clause; if out of contract, you are free to go. See exiting early.

"I changed my mind after agreeing"

There is no cooling-off right. Even a phone agreement can bind you. See can I cancel a new contract.

Moving premises or taking over a site

Ofgem advises you to check whether you can arrange a contract before you move, and warns that using energy before you have a contract may put you on a deemed rate. See moving premises and deemed contracts.

Watch out: a letter of authority lets someone act for you with suppliers. Only sign one for an intermediary you have checked. See is it safe to sign a letter of authority.

Next steps

• Pull out your latest bill and find the end date.
• Get two or three quotes.
• Read the best time to switch and then choose.