How long does it take to switch business energy suppliers?

Most UK business energy switches complete in 2 to 4 weeks from signing. There is a mandatory 14-day objection window during which your current supplier can block the switch (usually only for outstanding debt or an in-contract switch). After that, the new supplier takes over on your agreed switch date with zero interruption to supply.

Can I switch business energy supplier if I have debt on the account?

If the debt is over 28 days old, your current supplier can object to the switch and you'll need to clear or dispute the balance first. Debt under 28 days does not usually block a switch. Disputed debts (billing errors, incorrect readings) don't count and you can push back. A broker can help negotiate a repayment plan or challenge deemed-rate over-charging.

What happens if I'm mid-contract?

You generally can't switch mid-contract without penalty. What you can do is sign a new contract now for a future start date — up to 6 months in advance with most suppliers. This locks in today's rate ahead of your renewal, which matters when the market is rising.

Do I need to tell my current supplier I'm switching?

No. Your new supplier handles all communication with the old one. You don't need to call, write, or notify anyone. The Letter of Authority you sign lets your broker or new supplier do it on your behalf.

Will my gas or electricity supply be interrupted during the switch?

No. The physical supply never changes — the same wires and pipes deliver the same energy. Only the billing entity changes. There is zero downtime, no engineer visit, and no equipment change.

Guide · 8 min read

How to switch business energy suppliers (UK, 2026)

Q: What if I'm on out-of-contract or deemed rates?

You can switch immediately with 30 days' notice — no renewal window to wait for. Deemed rates are typically 40–80% higher than contracted rates, so switching from deemed usually delivers the largest savings of any scenario.

A step-by-step guide from an independent UK broker. Timings, paperwork, the traps that cost businesses thousands — and the honest bit about how brokers get paid.

TL;DR — the 6 steps

1. Get your latest bill, MPAN/MPRN and annual kWh.
2. Compare quotes from every supplier — not just three.
3. Sign a Letter of Authority so a broker can tender for you.
4. Choose your contract (fixed vs flexible, 1–5 years).
5. Wait out the 14-day objection window.
6. Check your first bill matches the contract.

Typical timeline: 2 weeks from signing to switch. Zero disruption to supply.

Can you switch right now?

The answer depends on where you are in your current contract. Three scenarios cover almost everyone:

You're within 6 months of your contract end date

Yes — this is the normal renewal window. Most suppliers let you sign a new contract now for a future start date, locking in today's rate. This is the sweet spot: don't wait until the last week.

You're on out-of-contract or deemed rates

Yes — you can switch immediately with 30 days' notice. Deemed rates are typically 40–80% higher than contracted rates, so this is where the biggest savings live.

You're mid-contract with more than 6 months to run

Not without a termination fee. But it's worth getting a quote anyway — sometimes the savings on a new 3-year deal outweigh the exit cost, especially in a falling market.

The 6 steps in detail

STEP 01

Gather your usage data

You need three things: your latest bill (or a photo of it), your MPAN (electricity) or MPRN (gas) number, and your annual kWh usage. All three are on any recent bill. That's it — no engineer visit, no meter change.

STEP 02

Compare the whole market

This is where most businesses lose money. Getting three quotes from three suppliers is not comparing the market — it's comparing three suppliers. The UK has 25+ business energy suppliers, and rates for the same usage profile can vary by 30–40% on any given day. A broker (or a very patient afternoon) is the only way to see all of them.

STEP 03

Sign the Letter of Authority

The LOA lets your broker request quotes from suppliers on your behalf. It does not give anyone the power to switch you without your written approval — it's a permission slip to gather quotes, nothing more. Read it before you sign, and make sure it names a specific broker (not an open-ended arrangement).

STEP 04

Choose your contract

You'll be comparing on three axes at once: fixed vs flexible pricing, contract length (1–5 years), and the split between unit rate and standing charge. Fixed 24-month is the default recommendation for most SMEs — long enough to smooth out short-term market noise, short enough not to trap you.

STEP 05

Objection window & switch date

Once you sign the new contract, your new supplier notifies the old one and a statutory 14-day window opens. The outgoing supplier can only object for a specific reason: outstanding debt over 28 days, or an in-contract switch. If neither applies, the switch goes through automatically on your agreed date.

STEP 06

Check your first new bill

When your first bill arrives, check three things against the contract: unit rate (p/kWh), standing charge (p/day), and the opening meter reading. Discrepancies are rare but easy to fix in the first bill cycle and painful to unpick later.

Rather have someone do this for you?

We tender the whole market, present the top 3 options, and handle the switch end-to-end. Free — we're paid a fully-disclosed commission by the supplier.

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4 traps that cost UK businesses thousands

After several hundred switches, these are the four we see most often — and the ones your current supplier won't warn you about.

Blend-and-extend offers from your current supplier

Your supplier may offer to 'blend' a new rate into your existing contract to keep you. It almost never beats a fresh whole-of-market tender — the blend is designed to protect their margin, not yours.

Deemed and out-of-contract rates

If you let your contract lapse without a new one in place, you roll onto deemed rates — typically 40–80% higher than contracted rates. Set a calendar reminder 6 months before your end date.

Auto-renewal clauses

Some older contracts auto-renew for a further 12 months if you don't give notice in a specific window (often 30–90 days before expiry). Check the small print on any contract signed pre-2022.

'Free' broker services with hidden uplift

All brokers are paid a commission by the supplier. Reputable ones disclose it in pence per kWh on every quote. If a broker won't tell you their commission, assume the worst and walk away.

Broker vs DIY vs going direct to a supplier

An honest comparison from a broker. Sometimes going direct really is the right call.

	Broker	DIY (call round)	One supplier direct
Suppliers compared	18+ (whole market)	3–5 (whoever picks up)	1
Your time investment	~30 min	6–12 hours	1 hour
Cost	Free (supplier-paid commission)	Free	Free
Best for	Most SMEs, multi-site, complex usage	Very simple single-meter site	Loyal to one brand
Ongoing renewal watch	Included	You track it	They call you at renewal

How brokers actually get paid

Every UK business energy broker is paid a commission by the supplier — typically 0.1p to 0.8p per kWh baked into your unit rate. It doesn't come out of your pocket separately, but it is part of what you pay.

A reputable broker discloses the pence-per-kWh commission on every single quote, before you sign. Aston Energy does this by default. If your broker won't put their commission in writing, that's the answer to whether you should use them.

Frequently asked questions

Related guides & pages

Our 4-step switching process — how we handle the tender on your behalf
Everything you need to know about fixed-price contracts — the pricing structure most SMEs choose
Business energy — sectors we cover
The 18+ UK suppliers we tender

Skip the six steps — we'll do them for you

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