When you move into business premises, the energy usually keeps coming from the previous occupant's supplier, on a deemed contract that can cost a lot more than a negotiated deal. You pay for what you use from day one, so take readings, prove the change of tenancy and agree a contract quickly.
This is general information, not legal or financial advice.
Who supplies the energy when you move in?
If there was a previous tenant, Citizens Advice says their supplier will carry on supplying the premises. Ofgem says that if you haven't arranged a contract, "you will be put on a deemed contract automatically when you move into a new premises". Deemed rates are usually higher than negotiated rates.
You can't avoid the cost by waiting. Ofgem is clear: "You are responsible for any energy you use in the period before your new contract starts."
Two other things to check before you sign the lease:
- Connection. Citizens Advice says you might have to pay a connection fee if the previous tenant was disconnected or the property is new.
- Who pays. Ofgem suggests checking whether your tenancy agreement includes energy costs. If the landlord supplies and recharges energy, the rest of this guide may not apply in the same way.
How do you find out who the supplier is?
Gas: search the property's postcode on the Find My Supplier website, or call the Meter Number Helpline on 0870 608 1524. Citizens Advice says it is open Monday to Friday, 8:30am to 5pm, and calls cost 7p a minute plus your phone company's access charge (as of October 2026). Ask for the Meter Point Reference Number (MPRN).
Electricity: find the local network operator by postcode (the Power Cut 105 website does this), then use that operator's website to find the supplier. You will want the Meter Point Administration Number (MPAN), which identifies the meter and supply.
Citizens Advice's tip: if one company supplies both fuels, the gas route is often the quicker way to find it. Our business energy glossary explains MPAN, MPRN and the other terms you will meet.
What proof will the supplier ask for?
You need to show there has been a change of tenancy. Citizens Advice says to give at least one of these:
- confirmation from your landlord, if you rent
- confirmation from your solicitor or estate agent
- a copy of your business rates statement
- your mortgage completion letter, if you bought the property
Ofgem's guidance also lists tenancy or lease agreements, property sale documents and title deeds. If the first evidence isn't enough, a supplier can ask for more, such as mortgage documents or letters from your bank, solicitor or landlord. It must explain why your evidence isn't enough and what else it needs.
Ofgem says the supplier will review your documents within 10 working days. It will then close the old account and open a new one, reject the change with reasons, or ask for more information.
Why do the meter readings on day one matter?
Your first-day readings separate your energy from the last occupant's. Citizens Advice says to photograph the gas and electricity meters on your first day and note the date, even if they are smart meters, then confirm the readings with your supplier "to make sure you aren't overcharged".
If a bill later includes energy used before you arrived, those dated photos and your change-of-tenancy proof are your evidence. If a large catch-up bill arrives for older usage, our guide to business back-billing rules explains the limits.
How do you get off the deemed contract?
Citizens Advice says to arrange a better deal with the current supplier or a new one "as soon as possible". Our guide to deemed and out-of-contract rates covers this in detail.
If you are moving in and switching at the same time, Ofgem says to tell both the current and the new supplier and give evidence to both. The new supplier starts the switch. The current supplier accepts it if it agrees there has been a change of occupier, and must give a reason if it rejects it.
Before you sign anything, Ofgem suggests checking:
- the contract type and length
- any fees, including special clauses
- what protections you have
- whether broker fees or commission are built into the price
- what happens at the end of the term, such as automatic renewal or out-of-contract rates
Ofgem also warns that "there is no cooling-off period after you agree to your contract". Agreements made by phone can count, as our guide to verbal business energy contracts explains. If you use a broker, see how to check a broker before signing.
What about the premises you're leaving?
Moving doesn't end your old contract by itself. Ofgem suggests reviewing its terms and checking whether the account is in credit or debt, and notes that most suppliers won't let you switch before a contract ends.
Citizens Advice says to:
- tell your supplier the date you're leaving as soon as you can
- give a new business or forwarding address
- photograph the meter readings on your last day and note the date
- switch everything off
If you don't close the account, Citizens Advice warns you might be charged for energy the next tenant uses.
What protections apply, and who can help?
Ofgem says you are a microbusiness if you have fewer than 10 employees and an annual turnover or balance sheet of no more than £2 million, or use no more than 100,000 kWh of electricity or 293,000 kWh of gas a year. Microbusinesses get extra protections, such as clear contract information and renewal prices before a contract ends. See are you a microbusiness? for the full picture.
If a supplier is slow, rejects your change of tenancy or bills you wrongly, use its complaints process first. Ofgem says to complain if decisions take longer than 10 working days or a request for more information seems unreasonable. A supplier has 8 weeks to resolve a complaint, unless it sends a deadlock letter sooner. Microbusinesses and small businesses can then go to the Energy Ombudsman, which is free. You must escalate within 12 months of a deadlock letter.
What to do next
- Check whether your lease includes energy costs or the landlord recharges them.
- Find the gas and electricity suppliers, MPRN and MPAN for the new premises.
- Gather one piece of change-of-tenancy proof, such as a landlord letter or rates statement.
- On day one, photograph every meter with the date and send the readings to the supplier.
- Compare offers and agree a contract quickly, so you spend as little time on deemed rates as possible.
- At the old premises, give notice, a forwarding address and dated final readings.
- Chase the supplier if it hasn't processed your change of tenancy within 10 working days.
- Use the estimator to see roughly what the new premises should cost to run.