The 5 Biggest Mistakes People Make When Switching Electricity Suppliers (UK)

Biggest mistakes people make when switching electricity suppliers in the UK

The biggest mistakes people make when switching electricity suppliers are:

1. leaving the switch too late and rolling onto a standard variable tariff,
2. comparing deals using guessed usage or headline monthly prices,
3. ignoring exit-fee timing rules,
4. not checking meter or tariff compatibility,
5. skipping switch-day and post-switch admin.

If you fix those five issues, switching is usually straightforward and you keep more of the saving.

Mistake 1: Waiting until after your fixed deal ends

When fixed deals end, households are usually moved to their supplier's standard variable tariff (SVT). That can raise your costs if better fixed deals are available.

Citizens Advice says fixed-tariff customers can usually switch without an exit fee when they have 49 days or less left on the contract, and that people are usually moved to an SVT at the end of fixed terms.

What to do instead:

• Check your tariff end date now.
• Start comparing around 6 weeks before end date.
• Set a calendar reminder so you do not miss the 49-day window.

If this already happened:

• You can still switch from an SVT at any time.
• Prioritize speed over perfection and move to a better tariff, then review again at your next renewal point.

Mistake 2: Comparing by headline monthly payment, not real cost

Many first-time bill managers choose the tariff with the lowest-looking direct debit. That is not always the cheapest overall deal.

Ofgem is clear that bills are driven by unit rates, standing charges, and usage. The price cap also does not cap your total bill, only capped rates for relevant default tariffs.

What to do instead:

• Use your actual annual kWh from your latest bill.
• Compare total annual cost (unit rate + standing charge), not just the advertised monthly amount.
• Re-run the comparison if your usage changed (for example, home working, new housemate, storage heating).

If this already happened:

• Recalculate your annualized cost using your real usage.
• If the deal is poor, check exit-fee terms and plan the cheapest route out.

Mistake 3: Ignoring exit fees and the 49-day rule

Switching early can still be worth it, but only if net savings beat all fees.

Citizens Advice states:

• with 49 days or less left on a fixed tariff, you can usually switch without an exit fee,
• with 50 days or more left, you might pay an exit fee.

What to do instead:

• Check your exact tariff end date and exit fee per fuel.
• Do a net-savings check: expected annual saving minus total exit fees.
• If net savings are small, wait for the 49-day window and switch then.

If this already happened:

• If you have already paid fees, focus on reducing future losses (set renewal reminders now).
• If terms were unclear, ask the supplier for a written breakdown and raise a complaint if needed.

Mistake 4: Assuming smart meter, prepayment, or meter type means "I cannot switch"

Many people stop here and overpay for months.

Primary guidance says:

• You can still switch with a smart meter.
• But you should check if it will stay in smart mode after the switch.
• Not all suppliers support all prepayment or multi-rate setups.

What to do instead:

• If you have a smart meter, check smart-mode compatibility before switching.
• If you are on prepayment or Economy 7/time-of-use, confirm the new tariff works with your meter.
• If you rent and your landlord pays the supplier directly, ask your landlord to switch because you cannot switch yourself in that setup.

If this already happened:

• If your meter stops operating in smart mode, submit regular readings while the issue is fixed.
• If you were told you cannot switch, confirm your payment setup (tenant-paid versus landlord-paid) and challenge bad advice with official guidance.

Mistake 5: Skipping switch-day and post-switch checks

Even when the tariff choice is good, admin misses can erase savings.

Common misses:

• not taking a meter reading on switch day,
• not checking your final bill from the old supplier,
• not chasing credit refunds or compensation.

What to do instead:

• Take and store a meter reading on switch day.
• Check your final bill arrives within 6 weeks.
• Check any credit is refunded within 10 working days of the final bill.
• If your switch is delayed beyond 5 working days (when eligible), check compensation.

If this already happened:

• Contact the supplier in writing with dates and meter readings.
• Ask for compensation under Ofgem guaranteed standards where applicable.

What to do if one of these mistakes already cost you money

Use this recovery plan:

15-minute pre-switch checklist for first-time bill managers

This is the practical version for students, renters, flat-sharers, early-career households, and first-time movers:

1. Find your tariff end date and current tariff name.
2. Confirm if you are inside the 49-day no-exit-fee window.
3. Pull annual kWh usage from your latest statement.
4. Compare whole-year cost, not only monthly direct debit.
5. Check meter compatibility (smart mode, prepayment, Economy 7/time-of-use).
6. Decide your switch date (immediately or timed to contract end).
7. Take switch-day meter readings and keep a photo.
8. Track final bill, refund, and compensation deadlines.

FAQs

What are the biggest mistakes people make when switching electricity suppliers?

The most expensive mistakes are switching too late, ignoring exit-fee timing, using estimated usage, choosing by headline monthly price, and skipping post-switch checks.

Can I switch energy supplier if I have a smart meter?

Yes. You can switch, but you should check whether your meter will keep working in smart mode after switching.

Will my gas or electricity supply be interrupted when I switch?

No, switching is an administrative process. Your supply stays on while the account moves between suppliers.

What if my switch takes too long?

For domestic customers, suppliers should complete eligible switches within 5 working days. If they do not and conditions are met, you may be due compensation.

Related guides

• Can I Switch Energy Suppliers If I Have a Smart Meter?
• How Much Can I Save by Switching Energy Suppliers?
• How to switch and save more in the UK

Sources used for this guide

• Ofgem: Switch energy supplier
• Ofgem: Get compensation for problems switching energy suppliers
• Ofgem: Energy price cap and standing charges explained
• Ofgem: Are you owed money on your energy bill?
• Citizens Advice: Switch energy supplier or tariff
• Citizens Advice: Switching if you're renting