Change of Tenancy Business Energy Guide

Quick Summary

A change of tenancy (CoT) is the process of transferring responsibility for a business energy supply when you move into or out of premises. Until it’s processed, you’ll be on a deemed contract with the existing supplier at rates that can be two or three times higher than a negotiated deal. You can switch away immediately with no exit fees. The key is to start the process the day you get the keys, take a meter reading, and line up a new contract while the CoT is being processed.

In this Guide

What a change of tenancy actually means for your energy
The process if you’re moving in
The process if you’re moving out
What evidence do suppliers need?
The 10 working day rule
Deemed rates and why speed matters
Switching suppliers during a change of tenancy
The previous tenant’s debt isn’t yours
Your energy bill after the move
A quick checklist for moving day

You sign the lease on a Friday. The keys arrive Monday morning. By lunchtime you’ve got desks going in, internet being set up, and a to-do list that could fill a wall. Somewhere near the bottom of that list, probably below “order bins” and above “sort parking permits”, is the energy supply. That’s the one that’ll cost you if you ignore it.

Moving into new business premises triggers something called a change of tenancy, or CoT, on your energy supply. It’s the formal process of transferring responsibility for the gas and electricity at that address from the old occupier to you. Get it sorted quickly and you’ll barely notice it. Leave it, and you’ll end up on deemed contract rates that can run two or three times higher than a negotiated deal.

Most businesses don’t find out about deemed rates until the first bill arrives. By then they’ve already been paying over the odds for weeks.

What a change of tenancy actually means for your energy

A change of tenancy isn’t a contract. It’s a regulatory process that transfers the energy supply at a property from one business to another. The supply itself doesn’t get disconnected or switched off. The meter keeps running. What changes is who’s responsible for paying for the gas and electricity flowing through it.

When the previous tenant moves out and you move in, you automatically enter into what’s called a deemed contract with whatever supplier was already providing energy to the premises. You didn’t choose that supplier. You didn’t agree to their rates. But under the Electricity Act 1989 and Gas Act 1986, the moment you start consuming energy at that address, you’re deemed to have a contract with them.

The rates on a deemed contract are almost always the most expensive a supplier offers. They’re variable, they’re not negotiated, and they’re designed to be temporary. The supplier knows you haven’t shopped around, so there’s no competitive pressure on the price. Think of it as the energy equivalent of paying rack rate at a hotel when everyone else booked in advance.

The good news is you can switch away from a deemed contract immediately. There’s no tie-in period, no exit fees, and no minimum term. You just need to get the change of tenancy processed and a new contract in place.

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The process if you’re moving in

Contact the existing energy supplier for the property as soon as you can. Ideally, you’d do this before you physically move in, but in practice it often happens in the first week. The supplier needs to know that the occupier has changed so they can close the previous tenant’s account and open yours.

You’ll need to give them a few details. The date you took responsibility for the premises. Your business name and registration number. A meter reading from the day you moved in, or as close to it as possible. That meter reading matters. Without it, the supplier will estimate the split between what the previous tenant used and what you’ve used, and estimates rarely work in the new tenant’s favour.

If you don’t know where the meter is, your MPAN number (for electricity) or MPRN (for gas) will help the supplier identify the supply point. You’ll find the MPAN on a previous electricity bill for the property, or your landlord or managing agent should have it. The MPRN works the same way for gas.

Take a photo of the meter on your first day. Sounds obvious, but it’s the single most useful thing you can do. It protects you from being billed for the previous tenant’s usage and gives you a clean starting point.

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The process if you’re moving out

Your obligations when leaving are simpler but just as important. Notify your energy supplier in writing, ideally at least 30 days before your move-out date. Give them a final meter reading on your last day, and make sure you’ve settled any outstanding balance.

If you’re on a fixed-term contract that runs beyond your move-out date, things get more complicated. Most business energy contracts don’t automatically end when you vacate. You may still be liable for the remaining term unless the new tenant agrees to take over the contract, or your supplier agrees to an early termination. Some contracts include a change of tenancy clause that allows for this. Many don’t.

Check the terms before you sign the lease on new premises. If your existing contract has eighteen months left to run, that’s eighteen months of charges you might still owe even after you’ve left.

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What evidence do suppliers need?

Since June 2025, the rules on what evidence a supplier can ask for have been tightened considerably. REC Schedule 33 now sets standardised requirements across the industry, which means suppliers can’t keep asking for obscure paperwork to delay the process.

Typically, you’ll need one or two of the following: a signed lease or tenancy agreement for the property, a Land Registry title document such as a TR1 transfer form, business rates correspondence from the local council, a solicitor or accountant’s confirmation letter, or Companies House filings if the legal entity has changed.

The supplier can’t demand documents that a reasonable occupier wouldn’t be expected to have. That’s a direct rule under the new framework, and it’s there to stop the practice of suppliers stringing out CoT requests with increasingly unreasonable evidence demands. Before these rules came in, some suppliers would ask for documentation that took weeks to obtain, leaving the business stuck on expensive deemed rates the entire time.

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The 10 working day rule

Under REC Schedule 33, your supplier has 10 working days to review your CoT evidence and either confirm the change or tell you exactly what’s missing. If they request additional documents, the clock resets to another 10 working days from when you provide them.

That timeline is enforceable. Before this rule existed, there was no standard timeframe, and some CoT requests dragged on for months. Businesses were stuck on deemed rates with no leverage to speed things up. Now, if a supplier doesn’t respond within the 10-day window, or if they keep asking for unreasonable additional evidence, you’ve got grounds to escalate.

The Energy Ombudsman handles disputes where the supplier hasn’t followed the process. Citizens Advice can also point you in the right direction if you’re unsure of your rights.

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Deemed rates and why speed matters

Every day you spend on a deemed contract is a day you’re paying more than you need to. The difference between deemed rates and a competitive fixed deal can be significant, particularly for electricity where out-of-contract and deemed rates tend to carry the widest margins.

Some suppliers offer backdating, where they apply your new negotiated rates back to the date you took responsibility for the supply. It’s not guaranteed and not every supplier will do it, but it’s worth asking about. If you can prove you moved in on a specific date with a meter reading to back it up, some suppliers will adjust the billing retrospectively once your new contract is live.

The practical takeaway is simple. Start the change of tenancy process the day you get the keys. Don’t wait until you’re settled in. Don’t wait until you’ve “had a chance to look at it.” Every week of delay is a week on deemed rates.

If you’re moving into a property where the previous supplier was EDF, British Gas, or SSE, it’s worth checking their specific deemed tariffs so you know exactly what you’re being charged while the CoT processes.

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Switching suppliers during a change of tenancy

You don’t have to stay with the incumbent supplier. Once the CoT is processed and the supply is in your name, you can switch to any supplier you like. And because deemed contracts have no lock-in, you can start the switching process straight away.

In fact, it often makes sense to run the CoT and the supplier switch in parallel. Notify the existing supplier that you’ve moved in and provide your evidence. At the same time, compare business energy prices and line up a new contract so it kicks in as soon as the CoT is confirmed. That way you minimise the time spent on deemed rates.

A broker can handle both sides of this at once. The CoT paperwork goes to the incumbent supplier while the broker secures quotes from the wider market. When the CoT completes, the new contract is ready to go live.

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The previous tenant’s debt isn’t yours

One thing that catches new tenants off guard is suppliers chasing them for the previous occupier’s arrears. This happens more often than it should, and it’s straightforward to deal with once you know your rights.

Under the Electricity Act and Gas Act, a deemed contract begins from the point the new occupier starts taking supply. The previous tenant’s debt belongs to the previous tenant. A supplier can’t refuse to process your CoT because the old tenant owes them money, and they can’t transfer that debt to your account.

If a supplier tries this, push back. Reference the legislation. If that doesn’t work, the Energy Ombudsman will sort it out. This is one of the more clear-cut areas of energy regulation, and suppliers know it. Usually a firm, informed response is enough to resolve it.

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Your energy bill after the move

Once the CoT is processed and your new contract is live, your energy bill should look normal. But it’s worth checking the first couple of bills carefully to make sure the meter readings line up with what you submitted, the rates match your agreed contract, and you haven’t been charged for any period before your move-in date.

Understanding what each line means on your bill can save you from overpaying. Your electricity bill in particular will include charges beyond just the unit rate: network charges, levies, and standing charges that vary depending on your meter type and region. The standing charge is worth paying attention to, because it’s a fixed daily cost you’ll pay regardless of how much energy you use.

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A quick checklist for moving day

Photograph every meter on the day you get the keys. Write down the readings and the date. Find the MPAN and MPRN numbers for the property, either from the landlord, the managing agent, or previous bills. Call the existing supplier that same day to notify them of the move. Gather your evidence documents: lease agreement, business rates letter, or solicitor’s confirmation. Start comparing energy deals immediately so a new contract is ready the moment the CoT completes.

Thirty minutes of admin on day one saves weeks of overpaying on deemed rates. That’s a trade most businesses would take if they knew about it early enough.

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