Between estimated bills and annual bills based on your actual energy consumption, sometimes it can be hard to know where you are. Energyprice takes a look at what both are for.


Your electricity or gas supplier (Engie Electrabel, Eni, Eneco, etc.) sends you different types of bills over the year. While they are all linked to your electricity or gas consumption, they are not actually based on the same data. So what are you actually paying? How are your bills prepared? Explanations.

Reading your energy meter provides a basis for calculating your actual consumption

In Belgium, your electricity or gas meter is generally read once a year at the request of the DSO (ORES, Sibelga, Resa, etc.). This operation is essential, because without it there is no other way of measuring your actual energy consumption. Comparing the reading with the previous reading reveals the number of kilowatt-hours (kWh) consumed during a given period, such as the last twelve months. For a single-rate electricity meter, the annual electricity consumption calculator proceeds as follows:

  • Reading on 1 January 2017: 2,585 kWh
  • Reading on 5 January 2018: 3,206 kWh

Electricity meterIn this example, the consumption period represents 370 days. We can then use cross-multiplication to find the number of kilowatt-hours consumed in a year.

→ 3,206 – 2,585 = 621 kWh of electricity consumed in 370 days, or 612 kWh in a year.

Once the new reading has been recorded by the DSO, it is sent directly to the energy supplier so they can prepare the annual bill, also known as the adjustment bill. Depending on the total amount already paid during the year in response to intermediate bills, you will receive a credit note, or a debit note if a supplement remains to be paid.

Tired of having to pay more every year when you receive the adjustment bill? Are you thinking seriously about cancelling your current energy contract and finding a better one? Check out our hints and tips on reducing the cost of electricity! If you would like personalised advice, don’t hesitate to contact our energy specialists on 0800 37 456.

The number of intermediate bills does not affect the energy consumption calculator

Most gas and electricity suppliers let their customers choose when to pay their bills. This freedom, enabling everyone to spread out their spending in the way that suits them best, has no impact on the adjustment bill. However, the billing frequency determines the number of estimated bills you will receive:

  • Monthly: the customer receives a fixed bill every month. Note that if the energy rate is variable, suppliers can change the instalment amount. These monthly payments make it easier to manage your budget, because you never need to advance a large amount in one go.
  • Bimonthly (bills every two months): the supplier sends out five estimated intermediate bills in a year and one based on actual consumption. Of course, like the monthly bills, these must all be paid. Don’t wait for the annual bill before paying for your gas or electricity consumption.
  • Six-monthly: this fairly unusual type of payment requires the customer to pay a large amount every time, as only two bills are issued every year, one based on an estimate and the other on actual energy consumption.
  • The annual instalment to be paid in advance: some suppliers, such as Essent, offer a deal where customers pay a single instalment bill yearly when the contract is signed or renewed. In the first year, the amount to pay immediately is set based on the average electric bill of a Belgian household.

While the adjustment bill is calculated based on the meter reading, the same is not true for intermediate bills. These are generally estimated based on your consumption habits.

Your energy bill is estimated in three situations

Most of the time, your consumption for the coming year is determined based on your previous annual consumption figures, collected through meter readings. Once your future consumption has been estimated, your supplier just needs to calculate the annual amount due based on the electricity rates or gas rates quoted in your energy contract. If you have opted for monthly payments, this amount is simply divided by 12.

However, it is possible for the meter not to be read or to be considered wrong. This is when your gas or electricity consumption is estimated.

1. It was not possible to read the meter

Technician sent by the distribution system operator to read the meterIf the meter is only accessible when you’re at home, your DSO will inform you of the technician’s visit a few days in advance. It is then up to you to ensure he can easily read the meter. If you cannot be available, don’t hesitate to ask someone you trust to receive the meter reader instead of you. Other solutions: write the meter readings on a piece of paper displayed in a visible place, or send them to your DSO yourself via the web, by telephone or by post.

If, despite sending notice, your DSO does not manage to read your meters and does not receive readings from you, they are legally obliged to estimate your electricity or gas consumption. They do this by averaging the consumption figures read in previous years for your home, whether the energy was consumed by you by or a predecessor. They then send this estimate to your supplier, who uses it to establish a bill indicating what you have consumed, in theory, during the period in question.

Do you think your DSO’s estimate of your electricity or gas consumption is too high or too low? Contact them to tell them about your doubts! They may be able to make a correction. However, the simplest way of avoiding any inconvenience is just to send them your meter readings on time. After all, a correct reading means a correct bill.

Note: transferring the energy meters when moving house is vital. The first step is to read the meters at your old and new addresses. Then send the readings directly to the DSO operating in the area to avoid your consumption being mistaken for that of the previous or future occupant. Worried about getting it wrong? Call us free on 0800 37 456, and we can explain what to do.

2. Your DSO thinks the reader is wrong

Whether the reading on your gas or electricity meter was taken by a technician or by you, it can be wrong, often due to being written down incorrectly. In general, a reading may be wrong if it is inconsistent with the reading from the previous period. For example, it may be lower when it should logically be higher, or it may be abnormally high in view of your previous consumption history. In a situation like this, the DSO will probably not use the reading provided and instead will estimate consumption, unless it can carry out a check.

Note that if you have solar panels, your reading may be lower than the figure for the previous period if you have generated more electricity than you have consumed.

Tip from our advisers: have your consumption habits changed radically? When reading your meters, don’t hesitate to let your DSO know to avoid an estimate or an unnecessary check. The simplest way of doing this is to provide your readings by phone and tell them about the change at the same time.

3. Your electricity or gas meter is faulty

A customer complaining to her energy supplierAn incorrect meter reading being due to a faulty meter is unlikely but not impossible. First of all, if you think the reading is incorrect, tell your supplier’s customer service department, providing your EAN code and the reference of the bill you are questioning. They will then be able to identify you easily and ask your DSO to check the reading again. If they refuse to respond, write to the supplier’s complaints department, explaining that you think the bill was calculated from an incorrect meter reading. Still no joy? You still have one more option: refer the case to the regional energy mediation service. In Wallonia, this is the SRM, a body created within CWaPE.

Remember, if you suspect a fault in your electricity or gas meter, you are entitled to ask your system operator to come and check it. However, if the equipment proves to be working properly, you will have to pay the cost of the operation, which amounts to several hundred euros. Otherwise, you will not have to pay for the technician’s visit or for the replacement of the electricity or gas meter. In addition, the supplier will send you a corrective bill.

Your annual consumption estimate is calculated based on precise criteria

Are you moving into a property that has just been connected to the electricity or gas network? No idea how much energy you consume? To calculate the amount of your upcoming intermediate bills, your energy supplier will estimate your consumption, based generally on the following elements:

  • Your living habits, the number of people in your household, the area of your home, the age of your boiler and the number of electrical appliances.
  • An estimate of how electricity and natural gas costs will evolve.
  • Climatic conditions: even if your habits remain the same, you may consume more energy than before. When outdoor temperatures are low, your natural gas boiler works harder to maintain your usual level of comfort. It will thus consume more fuel.

Did you know? You can also be your own electricity usage calculator (or gas) or refer to the average energy consumption in Belgium as a guide. A family of three consumes 3,500 kWh of electricity and 23,260 kWh of gas per year on average. To estimate your energy bills as accurately as possible, you can call our advisers on 0800 37 456 or contact them by email (

The amount of your intermediate bills changes from one year to the next

Imagine the following situation: you have switched your gas or electricity supplier and you notice that your monthly bills have increased or fallen compared with the previous year. Why? There are three possible reasons for this phenomenon:

  1. Changes in the price of a kWh between different energy dealsEstimates have been revised following a meter reading: if you or your supplier estimated your energy consumption when signing the previous contract, the meter reading has probably revealed a gap between the hypothesis and the reality. The supplier then takes this gap into account to revise the amount of your next intermediate bill upwards or downwards.
  2. Your consumption habits have changed: buying new electrical appliances or a change in the make-up of your household will affect your bills. In these cases, don’t hesitate to adjust the amount of your instalment payments during the year to avoid nasty surprises when the annual bill is issued.
  3. You are benefiting from a different electricity or gas price: if you switch your electricity or gas supplier, you are no longer on the same energy deal as before. Remember, this approach is highly recommended – using an energy bill calculator to compare prices, you can immediately discover the cheapest energy deals. If you remain faithful to the same supplier for the second year in a row, you will no longer benefit from the promotions given to new customers. Your bill will thus naturally be higher. To turn things round, the solution once again is to switch supply company.

Need help to understand your energy bill or simulate your gas or electricity consumption? Our advisers are ready and waiting on 0800 37 456 from Monday Friday between 9 am and 12.30 pm and between 1.30 and 5.30 pm.