Cheapest electricity and gas supplier: one contract or two?

The cheapest electricity and gas supplier is almost never a single supplier. In the survey of 10 October 2026, a household in Wallonia pays €3,533 a year with the cheapest single supplier, and €3,479 by giving each energy to the best price. In Brussels, the same split is worth €235.

Which electricity and gas supplier is cheapest in October 2026?

For a reference household in Namur using 3,500 kWh of electricity and 17,000 kWh of gas a year, the single-supplier ranking looks like this. The amounts are all-in annual budgets, ranked on the recurring price and therefore excluding any welcome bonus.

Source: Callmepower survey, tables dated 10 October 2026, built on suppliers' tariff sheets and on calculations by the CREG, Belgium's federal energy regulator. The two amounts marked "about" are derived by subtraction from the published total.

One hundred and twenty-one euros separate first place from fifth. That is not much.

Now read the columns one at a time. The cheapest for electricity, EnergyVision, only comes second overall because its gas holds it back. The cheapest for gas, Ecofix, is only third for electricity. None of the five leads both columns.

€54 in Wallonia, €235 in Brussels: the price of a single contract

Here is the argument of this article: a single contract is a convenience service, and that service has a price you can calculate.

Take the best electricity offer and the best gas offer in each region, then compare their sum with the best single supplier. Nobody publishes that subtraction. Here it is.

Our own calculations on the survey of 10 October 2026. For Brussels and Flanders, only the top three for each energy are published: Engie is the only supplier present in both Brussels top threes, and none is in Flanders. The Brussels figure therefore compares the split basket with the only single supplier we can verify, not necessarily the best one.

In Wallonia, the single contract costs €54 a year, or 1.5% of the bill. In Brussels it costs €235, close to 7%. The difference comes from the shape of the market: in Namur, five suppliers sit within a whisker of each other on both energies, whereas in Brussels, where the choice is narrower, the cheapest for electricity does not sell the cheapest gas and the gap between specialists and generalists widens.

A single bill is a convenience subscription: €54 a year in Namur, €235 in Brussels.

Why is the cheapest for gas rarely the cheapest for electricity?

Because the two energies are not won on the same ground. Gas is decided by the price per kWh, electricity by the fixed annual fee.

A household that heats with gas uses about five times more of it, in kWh, than electricity. A gap of a tenth of a cent per kWh is worth €17 a year on 17,000 kWh of gas and €3.50 on 3,500 kWh of electricity. Conversely, an annual fee that is €65 higher is equivalent to 1.86 cents per kWh on electricity and only 0.38 cents on gas.

The survey shows it in two head-to-heads. On gas, Eneco posts a slightly cheaper kWh than Ecofix (7.56 cents against 7.63), which earns it €12 over the year, but its fee of €50 against €10 takes €40 back: Ecofix wins by €28. On electricity, EnergyVision charges a fee of €75 against €10 at Ecofix, a €65 handicap, and more than makes up for it with a fixed kWh at 13.57 cents against 16.94 on a variable tariff: a €118 gain, a €55 lead at the finish. The consumer organisation Test-Achats noted on 5 October that this EnergyVision fixed tariff had not moved and remained the cheapest fixed electricity offer on the market.

A supplier therefore builds its price list with two levers, and it is rare to be best placed on both at once. As for the dual fuel discount, the one that would reward combining, none of the price pages consulted on 10 October shows any. Offers presented as dual add up two prices that are published separately.

The objection: one bill, one point of contact

It is a serious one.

Two contracts mean two customer accounts, two monthly advance payments, two annual settlements that do not necessarily fall in the same month and two helplines to call when you move. For €54 a year, or €4.50 a month, many households in Wallonia will decide it is not worth the trouble, and they will not be wrong. The gap is smaller than what a well-set advance payment or one degree less on the thermostat brings in. It is also smaller than the margin of error of the ranking itself: one monthly re-indexation is enough to swap two offers that are €28 apart.

There is a second, quieter argument. The cheapest split basket often rests on a promotion or on an unusual formula. In Flanders, TotalEnergies gas costs €1,437 in the first year and €1,709 after that. In Brussels, the cheapest electricity offer is a formula called "1,800 kWh fixed", whose conditions need reading before you sign.

The nuance: the objection holds at €54. It no longer holds at €235.

Wallonia, Brussels, Flanders: three markets, three answers

The same split basket costs €3,479 in Namur and €2,986 in Antwerp. The €493 gap does not come from suppliers but from network tariffs, taxes and public service obligations, which differ from one region to another and from one distribution network operator (the DSO or GRD, the company that owns the local grid and that you cannot choose) to another. No change of contract will erase it.

Each region has its official comparison tool, run by the regulator and free of commission:

• Wallonia: the comparison tool of the CWaPE, the Walloon regulator, to be used one energy at a time.
• Brussels: BruSim, the tool of Brugel, the Brussels regulator, essential because some offers exist only in the capital.
• Flanders: the V-test of the VREG, the Flemish regulator, which separates the first-year price from the recurring price.
• All three regions: the CREG Scan, which also places your current contract, including one that is no longer on sale.

Run two simulations, one per energy, then a third with both ticked. It is the only way to see the gap at your address.

Should you lock in a fixed price now?

Not as a reflex. In its survey of 5 October 2026, Test-Achats finds that fixed prices in October beat the records set in September: in Wallonia, fixed gas went from 5.14 cents per kWh in March to 9.05, roughly €665 more a year for 17,000 kWh. Signing a fixed contract today means locking in a high winter price.

Yet the same survey adds an argument for splitting. Between the cheapest and the most expensive fixed contract, the organisation measures a gap of more than €410 on electricity and more than €480 on gas. Nothing obliges you to take the same formula for both energies: fixed for electricity, where a tariff that stayed low still exists, and variable for gas, is a trade-off that a single contract often rules out. Our comparison of fixed, variable and dynamic contracts covers the three formulas.

Switching one energy without touching the other

Gas and electricity are two distinct contracts, each identified by an EAN code. You can move just one. The new supplier handles the cancellation, and a household pays no termination fee; our article on termination fees sets out the limits.

The method comes down to four checks. Take your actual consumption over the last twelve months from your latest annual settlement. Compare the annual cost, not the advertised price per kWh. Read the fixed fee line, especially for electricity. Leave the welcome bonus out of the calculation, since it disappears in the second year.

To place suppliers beyond price (customer service, clarity of bills, origin of the energy), see our energy supplier ranking and the guide to choosing your supplier.

Sources and assumptions. Annual budgets, kWh prices and fixed fees: Callmepower, "cheapest energy supplier" page, tables dated 10 October 2026, for 3,500 kWh of electricity and 17,000 kWh of gas in Namur, Brussels and Antwerp, single-rate meter, ranking excluding welcome bonuses. On that page, the "all-in" price per kWh multiplied by consumption does not exactly give the annual budget shown: we used the annual budgets. The basket totals, the gaps between single and separate contracts, and the equivalences between fixed fee and kWh price are our own calculations. Fixed price trends and gaps between contracts: Test-Achats, 5 October 2026. Absence of a bundle discount: a finding limited to the pages consulted (Callmepower and Selectra, 10 October 2026), to be checked on the supplier's tariff sheet. Variable tariffs are re-indexed every month, so these rankings are a snapshot. No affiliate links.