Electricity adjustment bill too high in Belgium

A €600 electricity adjustment bill does not mean you consumed too much. In most cases, the instalment was simply too low. Here is how to check the statement line by line, dispute it if the meter reading is wrong, obtain a payment plan and stop the story repeating next year.

In short

• Three causes explain almost every steep adjustment bill: an underestimated instalment, an estimated meter reading, a mid-contract price rise.
• Before paying or disputing, compare the closing reading on the statement with what your meter actually shows.
• Minimum legal deadline: 15 days to pay, then a further 10 days after the reminder.
• A payment plan should be requested in writing as soon as the invoice arrives, not at the formal notice stage.
• Adjusting your instalment takes two minutes in the customer portal and removes the next surprise.

Why is an electricity adjustment bill so high?

Because it catches up, in one go, twelve months of gap between what you paid and what you consumed. A Belgian energy bill is read in two stages: monthly or quarterly instalments, which are estimated provisions, then an annual adjustment bill comparing those provisions with actual consumption read from the meter. If the estimate was low, the gap lands all at once.

Three causes cover most files, in this order of frequency:

• The instalment was underestimated. It is calculated from previous years' consumption history and the contract price. Anything that has changed since — one more occupant, a heat pump, an electric car, working from home — is not in there. The CREG points out that the instalment is an estimate, not a flat fee.
• The previous reading was estimated. Without a real reading, the supplier works on a projection. When the actual reading comes in, the correction sometimes covers two periods.
• The price went up mid-year. On a variable formula, the kWh price follows the markets quarter after quarter, while the instalment stayed frozen on the old rate.

The orders of magnitude help you place yourself. In August 2026, an annual electricity bill for a typical 3,500 kWh household ranged from €1,304 to €1,589 depending on the contract, meaning a coherent instalment of around €109 to €132 a month. A household paying €80 a month on that profile mechanically builds up €300 to €600 of debt over the year. It is not a supplier error: it is an arithmetic mismatch.

How do you check whether your adjustment bill is correct?

Start with the meter reading, not the amount. The total means nothing until you have validated the two numbers that produce it: the opening and closing readings for the billed period.

What you need: the adjustment bill, last year's adjustment bill, access to your meter and something to photograph it with. Time: 30 minutes. Cost: €0.

1. Read your meter today. Photograph the display with the date visible. On a dual-rate meter, note both readings (peak and off-peak); on a digital meter, scroll through the registers.
2. Compare the closing reading on the invoice with that reading. If the invoice shows a reading higher than what the meter displays today, the statement is based on an over-estimate: that is the strongest ground for dispute there is.
3. Check continuity with last year. The opening reading on this invoice must match the closing reading on the previous one. A break between the two signals an estimation gap.
4. Look for the "estimated" or "actual" label. It sits next to each reading. Two consecutive estimated periods almost always explain a brutal catch-up.
5. Break the amount down. A Belgian bill has four blocks: energy (around 40% of the total), grid costs (around 36%), taxes and levies (around 24%), plus VAT. Only the first block depends on your supplier; the other three are identical for everyone at equal consumption and municipality.

Step 5 is the one that defuses the most misdirected anger. On the bills I take apart, a large share of the perceived rise comes from grid costs or regional taxes, not from the supplier — switching contract changes strictly nothing there. The CWaPE and Brugel each publish an official decoding of those items for their region.

How long do you have to pay an adjustment bill?

At least 15 days from the date the invoice is sent, and the general terms cannot shorten that. If you do not pay within that window, the supplier sends a reminder which must grant you at least 10 further days.

Only then comes the formal notice, and only above a debt threshold: roughly €100 for an electricity-only invoice, roughly €200 for a combined electricity and gas invoice. That letter still leaves you fifteen days, invites you to negotiate a payment plan, and must inform you of your right to be assisted by the CPAS/OCMW or a debt mediation service.

In other words, more than a month passes between the invoice and any real risk. That window is not a licence to sit still: it is the period during which a written dispute or a payment plan request still costs you nothing. The Walloon portal Energie Info Wallonie sets out the full procedure and the protections that apply to protected customers.

How do you dispute an electricity adjustment bill?

In writing, before the due date, while paying the undisputed part. It is the combination of the three that makes the difference: a verbal dispute to the call centre leaves no trace, and simply stopping payment tips you into default despite a valid case.

Your letter or form must contain your customer number, the number of the disputed invoice, the 18-digit EAN code starting with 54, the amount disputed, the precise reason and your dated meter reading with the photo attached. I insist on the photo: it is the only item that counts as proof against an estimated reading.

Two distinct contacts, not to be confused:

• The supplier (Mega, Engie, Luminus, Eneco, OCTA+, TotalEnergies…) handles the calculation, the price and any corrected invoice.
• The grid operator (ORES, Fluvius, RESA or Sibelga) handles the meter itself. If you suspect a faulty meter or a physically impossible reading, it is the grid operator you ask for a check. The test is generally charged if the meter turns out to be compliant, free if it is at fault.

If the supplier does not reply or stands by a statement you believe is wrong, the free recourse is the federal Energy Ombudsman Service. A documented file — dated meter photos, the last two years' invoices, written exchanges — is typically handled there within a few weeks. Test-Achats also publishes a regularly updated dispute guide.

How do you get a payment plan if the amount is unaffordable?

Ask for it in writing as soon as the invoice arrives, not at the debt collection stage. A payment plan is an instalment arrangement negotiated with the supplier: you propose a monthly amount you can sustain, generally over three to twelve months, on top of your ongoing instalments. The earlier the request lands, the more readily the supplier agrees — once the file has gone to collection, fees are added and the room for negotiation shrinks.

Three free forms of support exist, and they are under-used:

• Your municipality's CPAS/OCMW, which can step into the negotiation and, depending on the situation, into the payment itself.
• Accredited debt mediation services, free of charge, which take over when several debts pile up.
• Protected customer status, which grants the social tariff and a softened collection procedure for households meeting the conditions.

The reflex I see far too often is silence: the household waits for the formal notice, hoping to find the money. It is exactly the opposite that works, because a supplier receiving an instalment request before the due date has no fees to recover and almost always says yes.

How do you adjust your instalment to avoid the next shock?

By changing it yourself in the customer portal, in two minutes, without going through customer service. It is the only action that treats the cause rather than the symptom, and the one almost nobody takes before being burned once.

Two simple rules for calibrating the amount. First, revise upwards when the event happens, not at year end: a heat pump or an electric car shows up on the bill twelve months later, but can be anticipated on installation day. Second, be wary of over-enthusiastic instalment cuts after a mild year — that is exactly the mechanism that manufactures next year's steep adjustment bill. Our guides to the best electricity supplier for a heat pump and for an electric car quantify those consumption jumps.

A voluntary meter reading twice a year, submitted through the customer portal, completes the setup: the supplier stops working on estimates, and the adjustment becomes a matter of a few dozen euros.

Does switching supplier reduce the next bill?

Yes, but not the one in your hand. The adjustment debt remains owed to the old supplier, and a closing invoice will be issued at the switch. Switching acts on the following twelve months, and there the gap is real: between the best- and worst-placed contract on the market, the annual bill for 3,500 kWh varied by nearly €285 in August 2026, for exactly the same electricity carried by the same grid. The CREG put the energy component alone between €0.106 and €0.202/kWh in mid-2026 — a twofold gap.

Watch the logic, though: if your adjustment bill comes from an instalment set too low, switching supplier without correcting the instalment will reproduce exactly the same scenario with the next one. Treat the cause first, then the price. And if you do switch, the procedure is free and carries no paid notice period: we set it out in our guide on how to cancel an electricity contract.

To place your current contract against the market, our ranking of the best electricity suppliers compares Belgian offers by consumption profile. A steep adjustment bill is unpleasant; ignoring it and starting again on the same instalment is worse.