Why has my energy direct debit gone up — and is it fair?

A fixed monthly direct debit is just your estimated annual cost, divided by 12. Your supplier follows roughly these steps:

• Estimate your usage for the next 12 months — from your past usage if they have it, or a typical figure for your property type and household size if they don’t.
• Apply your rates — multiply that usage by your unit rate and add the daily standing charge for each fuel.
• Adjust for your balance — add a bit if your account is in debit, take a bit off if you’re in credit, so the account lands roughly level over the year.
• Divide by 12 — so you pay the same flat amount every month, summer and winter alike.

That last step is the key. You don’t use a twelfth of your energy each month — you use far more in winter — but you pay a twelfth of the cost each month. That’s the whole point of a fixed direct debit: smooth, predictable payments instead of huge winter bills.

Because of that smoothing, your direct debit will look too high for half the year and too low for the other half:

• In spring and summer you use far less than you pay, so you build up credit on your account.
• In autumn and winter you use far more than you pay, and that summer credit is run down to cover the gap.

So a direct debit that looks high in June isn’t automatically wrong — you’re building the cushion that stops a brutal bill in January. A healthy account drifts into credit over summer and back towards zero by spring.

On top of this, suppliers usually build in a buffer — a little extra headroom so you don’t fall into debt if you use more than expected or prices rise mid-year. A small buffer is normal and protects you from a nasty catch-up bill. The problem is when the buffer is too big: you end up handing your supplier an interest-free loan and sitting on hundreds of pounds of credit you could be keeping.

When the Ofgem price cap changes, your unit rate and standing charge change with it (if you’re on a standard variable tariff). The same amount of energy now costs more — so your estimated annual cost goes up, and your direct debit goes up to match.

Direct debits often jump by more than the headline cap rise, for two reasons:

• Timing. If the cap rises just before winter, your supplier knows the expensive months are coming and recalculates your payments so you don’t fall behind.
• Catch-up. If your old direct debit was already a bit low, the new higher rates are applied on top of clearing that shortfall — so the increase can feel disproportionate.

For context, Ofgem confirmed the July 2026 cap rises 13% — about £18 a month extra for a typical dual-fuel home. If your direct debit went up by a lot more than that, it’s worth checking why. You can see exactly how the new cap hits your bill with the July 2026 calculator.

You can sanity-check it yourself in a few minutes. Run through these:

• Is it based on real readings? If your bills say “estimated”, the whole calculation could be off. Send an up-to-date meter reading first.
• Where’s your balance heading? A healthy account is in modest credit by the end of summer and near zero by spring. A large credit that keeps growing means you’re paying too much; a debit that keeps growing means too little.
• Do the rates match the cap? Check the unit rate and standing charge on your bill against the current price cap. If they’re higher, you may be on a poor tariff rather than just a high direct debit.
• Does roughly 12 × payment ≈ your annual cost? Twelve months of your direct debit should land near your estimated yearly cost. If it’s wildly above, the estimate may be inflated.

If you’d rather not do the sums by hand, that’s exactly what BillLuma is for — upload your bill and we’ll read the rates and usage and tell you in plain English whether what you’re paying looks normal.

If you think your direct debit is too high, you can ask your supplier to review it. Under Ofgem rules they must be able to explain how it’s calculated and review it if you think it’s wrong. Here’s how:

1. 1Submit a meter reading first, so any review is based on your actual usage rather than an estimate.
2. 2Contact your supplier — most let you adjust your payment in the app or online account; otherwise call or message them and ask for a direct debit review.
3. 3Ask them to explain the figure — what annual usage and rates they’ve assumed, and why. If their estimate looks too high, point to your readings.
4. 4Request a refund of spare credit if you’re sitting on a large balance you don’t need — you’re entitled to ask for it back.
5. 5Escalate if needed — if you’re not happy with their answer, you can raise a formal complaint and, after eight weeks, take it to the free Energy Ombudsman.

One word of caution: don’t set your direct debit unrealistically low just to pay less now. If it doesn’t cover your real usage you’ll build up debt and face a bigger catch-up later. The goal is a payment that matches what you actually use — no more, no less.