Moving business premises is complicated enough without the energy side of it turning into a months-long fight with your supplier. But that’s exactly what happens to thousands of UK businesses every year - stuck on deemed rates they didn’t agree to, chasing suppliers who won’t process their paperwork, and sometimes being told they owe money for energy the previous tenant used.
It doesn’t have to be this way. Since 27 June 2025, REC Schedule 33 (opens in new tab) has given businesses clear rights, standardised evidence requirements, and enforceable timelines for the first time. This guide covers everything you need to know.
TL;DR: The Quick Reference
| What | Detail |
|---|---|
| CoT = CoO | Change of Tenancy and Change of Occupier are the same thing |
| Supplier review SLA | 10 working days to review your evidence (REC Schedule 33) |
| Extra evidence SLA | Another 10 working days if they request more documents |
| Switching timeline | Minimum 2 working days after switch request (non-domestic) |
| Deemed rates | Automatic if you take supply without a contract - switch immediately |
| Previous tenant’s debt | You are NOT liable - Ofgem will act against suppliers who try this (opens in new tab) |
| Termination fees | Moving usually counts as early termination - check your contract |
| Supplier blocking | Suppliers cannot block a switch away from a deemed contract |
What is Change of Tenancy?
Change of Tenancy (CoT) - also called Change of Occupier (CoO) - is the process that happens when the business responsible for an energy supply at a premises changes. This includes moving into new premises, vacating premises, buying or selling a business property, or undergoing certain legal changes like converting from sole trader to limited company.
The industry uses both terms interchangeably. “CoT” is the commercial term you’ll hear from brokers and suppliers. “CoO” is the legal term in the Retail Energy Code (opens in new tab) (REC Schedule 1 defines it as a situation where “the consumer at a premises has changed or is due to change”). There is no difference in your rights or obligations - they’re the same process.
The deemed rates trap
This is the single most important thing to understand about moving premises: if you use energy before agreeing a new contract, your supplier will put you on deemed rates.
How deemed contracts work
Under the Electricity Act 1989 (opens in new tab) (Schedule 6, paragraph 3) and the Gas Act 1986 (Schedule 2B, paragraph 8), when someone takes energy supply “otherwise than in pursuance of a contract”, a deemed contract automatically exists between the occupier and the existing supplier from the moment supply begins.
In plain English: you walk into a new premises, the lights are on, and you’re already on a deemed contract with whoever supplied energy to the previous tenant. You didn’t sign anything. You didn’t agree to the price. It happened automatically by law.
Why deemed rates are expensive
Deemed rates are almost always higher than contracted rates. Ofgem’s guidance on deemed contracts (opens in new tab) (Standard Licence Conditions 7.3-7.4 - SLCs are the rules energy suppliers must follow as a condition of their Ofgem licence) acknowledges that suppliers can legitimately charge more for deemed customers to reflect higher risk and uncertainty - a deemed customer can leave at any time, so the supplier hasn’t hedged energy for them at a fixed price.
However, Ofgem also states that setting deemed rates at a very high level solely to coerce customers into fixed-term contracts is not acceptable. Deemed terms must not be “unduly onerous”.
The good news: you can switch immediately
Here’s the critical point most businesses don’t know: suppliers cannot block a switch away from a deemed contract.
Ofgem’s impact assessment on non-domestic objections confirms that deemed contracts are not in scope of the objection period rules (Standard Licence Condition 14.2) - the licence condition that normally allows suppliers to object to a customer transferring away. This means you can arrange a new contract with any supplier from day one. Don’t sit on deemed rates waiting for the CoT paperwork to resolve.
Step by step: leaving a site
If you’re the outgoing business vacating premises:
1. Notify your current supplier as soon as possible. Don’t wait until the day you leave. Tell them your move-out date, even if you’ve already arranged supply at your new premises.
2. Take a final meter reading on your last day. Photograph the meter and note the date. This protects you from being billed for energy used after you leave.
3. Provide a forwarding address for your final bill.
4. Provide evidence of vacating if requested - end-of-tenancy correspondence, lease termination letters, or solicitor confirmation.
5. Check your final bill carefully. Make sure it’s based on your actual final meter reading, not an estimate. Ensure there are no charges for energy consumed after your move-out date.
If you’re leaving before the end of a fixed-term contract, your supplier may charge termination fees. More on this below.
Step by step: moving in (keeping the existing supplier)
If you’re the new occupier and want to stay with the supplier already at the premises:
1. Contact the current supplier on the day you move in (or as close to it as possible). Tell them you’re the new occupier and provide an opening meter reading. Many suppliers have dedicated online CoT portals or forms on their website - check your supplier’s support pages first, as this is often faster than calling.
2. Provide evidence of occupancy. This is where REC Schedule 33 (opens in new tab) (effective 27 June 2025) now gives you clear rights. You’ll typically need one or two of the following:
- Signed lease or tenancy agreement
- Property sale documents or title deeds
- Land Registry title (e.g. TR1 transfer forms)
- Business rates bills or council correspondence for the site
- Solicitor, accountant, or landlord confirmation letters
- Companies House filings (if the legal entity has changed)
- Bank letters confirming the new address
You don’t need all of these - one or two strong documents is usually enough. The full list is in the documents section below.
3. Wait for the supplier’s decision within 10 working days. Under the new rules, the supplier must either:
- Accept the CoT and update accounts, or
- Reject the CoT with clear reasons, or
- Request specific additional evidence, explaining exactly what’s missing and why.
4. If they request more evidence, the supplier must tell you exactly what’s missing and why they need it. They can only ask for documents a reasonable occupier could be expected to have - they can’t keep adding new requests to delay the process. Once you provide the additional evidence, the supplier has another 10 working days to make a final decision.
5. Negotiate a new contract. Until you agree terms, you’ll be on deemed rates. Don’t delay - start discussing contract options immediately, even before the CoT paperwork is finalised.
Step by step: moving in and switching supplier
If you want to switch to a different supplier:
1. Inform both suppliers - the existing (incumbent) supplier and your chosen new (gaining) supplier.
2. Provide evidence of occupancy to both. Your new supplier will usually help with the paperwork.
3. The gaining supplier submits a Switch Request under REC Schedule 23. For non-domestic premises, the earliest supply start date is at least 2 complete working days after the switch request is submitted.
4. The losing supplier has an objection window - until 17:00 on the second working day after the switch request. They can only object for permitted reasons (e.g. you’re still in a fixed-term contract, or certain pre-2004 debts). They cannot object if you’re on a deemed contract.
5. Where the switch is flagged as a Change of Occupier, both the gaining and losing supplier must retain the evidence they relied on for at least one year (REC Schedule 23). This creates an audit trail in case of disputes.
What documents do you need?
Before REC Schedule 33, there were no standardised evidence requirements. Each supplier demanded whatever they wanted, and some demanded a lot. Ofgem’s enforcement action against Maxen Power Supply - which resulted in a £1.65 million payment (opens in new tab) - found that Maxen “put unreasonable requirements on customers to evidence a change of tenancy by asking for a large number of documents”, trapping customers on expensive deemed rates.
Now, REC Schedule 33 provides a non-exhaustive evidentiary list that standardises what suppliers can reasonably expect. There is no single mandatory form - but suppliers should align with this list:
- Signed lease or tenancy agreement
- Lease termination or surrender letters
- Property sale documents or title deeds
- Land Registry title (e.g. TR1 transfer forms)
- Business purchase or asset transfer agreements
- Business rates bills or council correspondence for the site
- Solicitor, accountant, or landlord confirmation letters
- Companies House filings (for entity changes)
- Mortgage documents
- Bank letters confirming the new address
The key rule: suppliers must not demand documents that a reasonable occupier could not be expected to have. If your supplier asks for something unreasonable, cite Ofgem’s Standards of Conduct for energy suppliers (opens in new tab) - which explicitly uses excessive CoT document demands as an example of conduct that may breach licence conditions.
Can you be held liable for the previous tenant’s debt?
No. The law is clear on this.
Deemed contract provisions under the Electricity Act 1989 and Gas Act 1986 take effect from the time the new occupier begins to take supply. The previous tenant’s debt belongs to the previous tenant.
Ofgem’s Standards of Conduct for energy suppliers provides a specific example of what suppliers must not do: threatening a new occupier with disconnection if they don’t pay the previous tenant’s debt, while simultaneously dragging out the CoT evidence process. This is explicitly cited as conduct that may breach their licence conditions.
The Maxen Power case (opens in new tab) is the clearest precedent. Ofgem found that new occupiers were threatened with disconnection unless they paid the previous tenant’s debt - despite having provided evidence they were a different legal entity. Maxen paid £1.65 million.
If a supplier tries to hold you responsible for someone else’s debt:
- Put your objection in writing, citing Ofgem’s Standards of Conduct for energy suppliers.
- Provide your evidence of occupancy again.
- If unresolved after 8 weeks (or if you receive a deadlock letter), escalate to the Energy Ombudsman (opens in new tab).
What happens to the previous tenant’s contract?
Most non-domestic energy contracts are site-specific - tied to a particular MPAN (electricity) or MPRN (gas) and address, not to the customer as a person or company.
When the previous tenant leaves:
- Their contract at that site ends (or enters early termination).
- The supplier may pursue termination fees from the outgoing tenant.
- You, as the new occupier, are not party to that contract. You start fresh on a deemed contract and can negotiate your own terms.
If you’re the one leaving before contract end
Moving premises before your fixed-term contract expires is typically treated as early termination. Your supplier may charge exit fees, usually calculated as:
- A percentage of remaining estimated charges, and/or
- A “loss of bargain” calculation based on remaining term and wholesale price movements. For example, if you signed a 3-year contract at 28p/kWh but wholesale prices have since dropped to 22p/kWh, your supplier locked in energy at a higher price on your behalf. If you leave early, they may charge the difference (6p/kWh) multiplied by your estimated remaining usage to cover their loss.
There is no licence condition or statute that automatically voids a non-domestic contract or waives termination fees because of a genuine CoT. It’s governed by contract law and Ofgem’s general fairness requirements for energy suppliers (the Standards of Conduct).
However:
- Microbusinesses get additional protections. If your contract was auto-renewed (i.e. your supplier rolled you onto a new deal without you actively agreeing), there are legal limits on what termination fees they can charge - this comes from a Competition and Markets Authority (CMA) order specifically protecting small businesses. However, this protection only applies to auto-renewed contracts, not if you’re leaving a contract mid-term because you’re moving premises.
- Some suppliers voluntarily waive fees if you transfer your supply to new premises with the same supplier. This is commercial goodwill, not a regulatory right - ask before assuming.
- For larger I&C customers, there are no specific regulatory protections on termination fees. Contract negotiation and general fairness principles are your main levers.
Legal changes at the same premises
You don’t have to physically move to trigger a CoT. Industry and REC guidance treat certain legal changes as CoO events, even if operations continue at the same address:
- Sole trader to limited company - a new Companies House number means a new legal entity is “occupying” the premises.
- Change of proprietor in a partnership - the “consumer” at the premises has changed.
- Business sale or asset transfer - a new company takes over the site.
These go through the same CoT evidence process. Suppliers tend to scrutinise them more closely because they’re higher-risk for fraud - the business hasn’t physically moved, only the legal entity has changed. The sole-trader-to-Ltd conversion in particular is difficult for suppliers to challenge, since a genuine conversion is indistinguishable from a fraudulent one on paper.
If you’re making a genuine legal change, prepare your evidence thoroughly. Companies House filings, the incorporation certificate, and solicitor confirmation of the conversion will usually satisfy the REC Schedule 33 requirements.
How long can you be stuck on deemed rates?
There is no minimum period. You can start arranging a new contract or switching supplier from the moment you move in. The regulatory position is unambiguous:
- Deemed contracts have no fixed term - you can get off deemed rates at any time by agreeing a new contract or switching supplier.
- Suppliers cannot block a switch away from deemed rates - the objection rules don’t apply to deemed contracts.
- Any unpaid charges on the deemed contract can still be pursued through normal debt collection, but they can’t be used to prevent you switching.
The practical bottleneck is usually your own speed in arranging a new deal. Don’t wait for the CoT paperwork to be finalised before shopping around. Get quotes, compare unit rates and standing charges, and have a contract ready to sign the moment the CoT is confirmed.
The bottom line
The CoT process used to be a mess - no standardised evidence, no timelines, and suppliers who could (and did) drag their feet while you sat on expensive deemed rates. Since June 2025, REC Schedule 33 has changed that. You now have clear evidence requirements, a 10-day review SLA, and Ofgem precedent showing they’ll act against suppliers who abuse the process.
The most expensive mistake businesses make when moving premises is doing nothing. Every day you spend on deemed rates without actively arranging a new contract is money wasted. Notify your supplier, gather your evidence, and start switching immediately.
This guide is based on Ofgem’s June 2025 “Change of tenancy for businesses” guidance, REC change proposal R0155 (Schedule 33 - Non-Domestic Change of Occupier), Ofgem’s Standards of Conduct for energy suppliers, the Electricity Act 1989, and Ofgem’s enforcement action against Maxen Power Supply. All regulatory references are current as of February 2026.