What is the Energy Switch Guarantee?

Last checked: 14 September 2026

Changing energy supplier can feel like a leap into the unknown, especially if you are doing it for the first time. Even if you have found a tariff that looks better suited to your household, it is natural to wonder what happens next. Will your gas or electricity be interrupted? Who sends your final bill? What if something goes wrong during the switch? This guide explains what the Energy Switch Guarantee currently covers, what it does not, and what you can do if you experience problems while changing supplier.

The Energy Switch Guarantee in brief

The Energy Switch Guarantee (ESG) is a voluntary industry commitment run by Energy UK, the trade association for the energy sector, with input from Ofgem and Citizens Advice. It was introduced to give customers extra reassurance when switching between participating suppliers. The guarantee sets out a number of commitments designed to make the switching process clearer and more straightforward, while explaining what customers can expect if something does not go to plan.

The Guarantee complements, rather than replaces, the wider consumer rights and regulations that protect all energy customers. Some of what's covered on this page, like the maximum five-working-day switching time and your 14-day cooling-off right, are things Ofgem requires of every supplier by law, regardless of ESG membership. Others, like the specific communication and problem-resolution commitments below, are voluntary extras that only ESG signatories promise. Where that distinction matters, this guide says so directly. The scheme covers domestic households in Britain, not business energy accounts.

What does the guarantee currently cover?

The Energy Switch Guarantee is designed to make the switching process more transparent by setting out what participating suppliers commit to doing throughout your switch. These commitments can change over time as Energy UK updates the scheme, but they are broadly focused on making the process easier to understand and resolving problems when they arise.

Which suppliers take part?

Not every energy supplier is part of the Energy Switch Guarantee. Participation is voluntary, which means suppliers choose whether to sign up to the scheme and follow its commitments.

Because membership can change over time, it is best not to rely on older articles or lists you may have seen elsewhere. If you are considering switching and want the reassurance of the scheme, check Energy UK's current signatory list.

A supplier not taking part does not automatically mean switching with them will be problematic. Energy suppliers must still meet wider regulatory requirements, and many switching protections exist outside the scheme itself, the Guarantee is an additional set of voluntary commitments, not the only protection you have.

Will your energy supply be interrupted?

One of the biggest concerns people have when changing supplier is whether they will be left without gas or electricity during the switch. Your energy supply is not expected to be interrupted, because switching changes the company that bills you for your energy, not the physical pipes, cables or meter that supply your home. All suppliers deliver through the same shared network. Participating suppliers also commit to keeping you informed and supporting you if anything else about the switch goes wrong.

If your main concern is whether your gas or electricity will turn off while you are changing supplier, we have covered this in more detail in our article, whether your energy will turn off during a switch.

How long does an energy switch take?

A switch to a new energy supplier should take no more than five working days, although you can ask for it to happen later. This is much faster than the up-to-21-day timeframe once commonly quoted by the industry. In practice, timings can still vary depending on the suppliers involved.

In many cases, the switch follows a straightforward process. After you have agreed to a new tariff, your new supplier manages most of the administration, keeps you updated and contacts your existing supplier where necessary. If anything could delay the switch, you should be told what has happened and what to expect next.

This five-working-day maximum is a requirement Ofgem sets for every domestic energy supplier, not something specific to Guarantee signatories, it applies whether or not your supplier has signed up to the ESG. For a deeper look at what can affect timing, see our guide to how long an energy switch takes.

What is the cooling-off period?

When you agree to switch energy supplier, you don't necessarily have to go through with the change immediately. You have a cooling-off period during which you can cancel if you change your mind. In the UK this is a statutory right, set out in Ofgem's switching guidance: every domestic gas and electricity customer gets a 14-calendar-day cooling-off period, starting from the day you sign your new contract, and it can't be waived by your supplier.

If you are unsure whether you are still within the cooling-off period or want to understand how it works, we have covered this in more detail in the cooling-off period.

What happens to meter readings and final bills?

The exact process can vary depending on your supplier and the circumstances of your switch but opening and closing meter readings are generally an important part of ensuring both suppliers calculate your bills correctly.

Your previous supplier is usually responsible for issuing your final bill, typically within around six weeks of the switch completing, while your new supplier uses the agreed opening reading to begin your new account. Any credit balance you are owed should be refunded within 14 days of that final bill. If something does not look right: an unexpected charge, or a reading that does not match your own records, contact your supplier as soon as possible so they can investigate.

If your final bill appears to be incorrect, our guide to what to do if your energy bill is too high explains the checks you can make before raising the issue with your supplier.

What if something goes wrong with the switch?

Most energy switches go ahead without any major issues, but delays, billing queries or account problems can occasionally happen. Which supplier to contact depends on the problem: a final-bill or credit-refund issue is usually one for your previous supplier, while a delayed switch or other process problem may sit with your new one. Keeping copies of emails, letters and any reference numbers can make it easier to resolve the issue if further investigation is needed.

If the relevant supplier can't resolve the problem through its usual customer service process, follow its formal complaints procedure. According to Ofgem's complaints guidance, you can escalate an eligible complaint to the Energy Ombudsman after eight weeks, or sooner if your supplier issues a deadlock letter first.

What the Energy Switch Guarantee does not mean

The Energy Switch Guarantee can provide additional reassurance, but it is important to understand what it does not promise. It does not guarantee you will save money by switching, and it does not mean every energy supplier or tariff is covered by the scheme.

It also does not remove the need to compare tariffs carefully. A smooth switching process matters, but it is only one part of choosing the right energy deal for your household.

Finally, it may not apply to every account type or switching scenario for instance, it covers domestic households rather than business energy accounts. Checking the current scheme guidance and your supplier's terms can help you understand what to expect before you switch.

Ready to compare energy options?

Once you understand the current switching protections and have checked scheme participation, you can compare energy options. It's still worth weighing up the overall tariff, unit rates, standing charges, contract length and any exit fees, rather than focusing on a single feature or introductory offer, since the right energy deal depends on your household's usage, budget and priorities.

Compare energy options

Frequently asked questions

Is every supplier covered by the Energy Switch Guarantee? 

No. Participation in the Energy Switch Guarantee is voluntary, so not every energy supplier is part of the scheme. It is worth checking the current participant list before assuming the Guarantee applies to your switch.

Will my gas or electricity be cut off during a switch? 

In normal circumstances, changing supplier should not interrupt your energy supply because you are changing the company that bills you rather than the physical network that supplies your home. See our guide to whether your energy will turn off during a switch .

Can I cancel after starting a switch? 

Yes. You have a statutory 14-day cooling-off period from the day you sign up to your new contract, set by Ofgem. During this time, you can cancel penalty-free and stay with your existing supplier or tariff.

What happens if the switch takes longer than expected? 

Contact your supplier first and keep a record of any emails, letters or reference numbers relating to your switch. If the issue is not resolved, follow your supplier's complaints process and, if it is still unresolved, you can escalate to the Energy Ombudsman after eight weeks or sooner if you receive a deadlock letter.

Who sends the final bill? 

Your previous supplier is generally responsible for issuing your final bill after the switch, typically within around six weeks of it completing. If anything does not look right, contact the supplier as soon as possible so they can investigate.

Where can I complain if the process goes wrong? 

Start with your new supplier's complaints process. If it is not resolved, the Energy Ombudsman can investigate eligible complaints.