Heat pump or gas boiler in a Belgian renovation: price, radiators and running costs (2026)
Short answer: In a Belgian renovation, an installed air-to-water heat pump costs roughly €5,000 to €20,000 according to the sources, against €1,800 to €5,200 for a new gas condensing boiler. The heat pump uses far less energy per year but performs best at low flow temperatures. In a poorly insulated house with old radiators, insulating first or going hybrid is often the safer route.
Prices in this article are indicative Belgian market ranges, not Alpha Services Benelux's price list. Your fixed price is in the quote.
What do a heat pump and a gas boiler cost?
An installed air-to-water heat pump runs from about €5,000 to €20,000, a gas condensing boiler from €1,800 to €5,200. Sources disagree, so the real price depends on capacity, brand and finish level.
| System | Range | What the sources say |
|---|---|---|
| Air-to-water heat pump (general) | €5,000 – €20,000 | €5,000–15,000, €7,000–13,000 and €8,000–20,000 depending on the source |
| Air-to-water up to 8 kW | €7,250 – €10,000 | One source, up to 8 kW |
| Air-to-water from 8 kW | €11,750 – €15,000 | One source, from 8 kW |
| Monobloc 5–8 kW / split 5–8 kW | €8,000 – €14,000 | Monobloc €8,000–12,000, split €10,000–14,000 |
| Hybrid heat pump with condensing boiler | €5,000 – €16,000 | €8,000–10,000 and €8,000–16,000 also quoted (note: not eligible for the 6% VAT rate, ask which rate the quote applies) |
| Gas condensing boiler | €1,800 – €5,200 | €1,800–4,500 and €2,000–5,200 depending on the source |
A three-phase connection adds €1,000 to €2,500 according to one source and is often needed from 8 kW. Premium brands cost 20 to 40% more than budget brands.
Does a heat pump work with existing radiators?
Yes, provided your radiators still heat the house at a low flow temperature. An air-to-water heat pump performs best at 30 to 45 °C; old radiators that need 70 °C reduce efficiency.
A sensible check is the 50-degree test: have a professional assess whether the house stays comfortable at a flow temperature of about 50 °C. If so, the current radiators can often stay. If not, low-temperature radiators or fan convectors are needed. That item is not in typical heat pump prices; the sources give no fixed amount, as it depends on the number and size of radiators.
A hybrid system is a middle route. According to one source, a hybrid gives quick results in a renovation with existing radiators and average insulation: the heat pump runs on mild days and the boiler steps in during frost.
Poorly insulated house: heat pump, gas boiler or insulate first?
In a poorly insulated house the heat pump must be larger and therefore dearer, and it uses more electricity. Insulating first is sometimes smarter, with a new boiler or hybrid system as a bridge.
- Capacity: according to one source, 30 to 50 W per m² with good insulation and 50 to 80 W per m² with average insulation. More capacity means a higher purchase price.
- Consumption: heat loss increases the heat pump's electricity use.
- Gas boiler: a comparison site says it works well in less-insulated houses with classic radiators.
- Hybrid: a useful compromise when insulating or replacing radiators is not possible right now (note: a hybrid system is not eligible for the 6% rate of a full heat pump, ask which VAT rate the quote applies).
For the order of works, read our guide insulate first or heat pump first.
Running costs per year: what does each system use?
Comparison sites put heating with a heat pump at roughly €800 to €1,200 a year, against €2,000 to €2,600 with a gas boiler. The gap depends on insulation, flow temperature and energy prices.
| System | Yearly consumption | Yearly cost |
|---|---|---|
| Air-to-water heat pump | 2,500 – 3,500 kWh electricity | €800 – €1,200 |
| Gas condensing boiler | 18,000 – 22,000 kWh gas | €2,000 – €2,600 |
A worked example from another source: 13,000 kWh heat demand, COP of 4, so 3,250 kWh of electricity, or €812.50 at €0.25 per kWh. Efficiency is not constant, though.
| Outdoor temperature | COP |
|---|---|
| +7 °C | ≈ 4.5 |
| 0 °C | ≈ 3.5 |
| −5 °C | ≈ 2.8 |
Seasonal efficiency (SCOP) of air-to-water heat pumps is 3.0 to 4.0. Payback is quoted at 7 to 12 years, or more broadly 5 to 15 years. It depends heavily on your house, your gas price and whether you have solar panels.
What drives the price in a renovation?
The capacity your house needs matters most, followed by installation, the heat emitters and the brand.
- Capacity and insulation: the poorer the insulation, the larger (and dearer) the unit.
- Installation: about €4,000 on average, ranging from €1,500 to €6,500 according to one source.
- Emitters: low-temperature radiators, underfloor heating or fan convectors sometimes come on top.
- Electrical connection: three-phase can add €1,000 to €2,500.
- Hot water: a 150 to 300 litre cylinder is not always included.
- Finish level and brand: premium brands are 20–40% dearer.
For a gas boiler, the type (combi, with cylinder, standalone), the flue and the installation matter most.
VAT: 6% or 21%?
In a home older than 10 years, a heat pump carries 6% VAT; since 1 January 2026 that rate has been extended for five years, also covering newer homes and new builds (Test-Aankoop). Since July 2025, supplying and installing a new gas or oil boiler carries 21% VAT, even in homes older than 10 years (Test-Aankoop; circular 2025/C/47). The transition rule ended on 30 June 2026. Hybrid heat pumps are excluded from the 6% measure (Test-Aankoop; circular 2026/C/19): ask which VAT rate the quote applies to a hybrid system.
Conditions for 6%: a private dwelling and work done by a professional who invoices you directly. If you buy the materials yourself, 21% applies. Repair and maintenance of an existing gas boiler stays at 6% in a home at least 10 years old. Always check on the quote which rate is applied and whether the price includes VAT.
Grants differ by region and change often: check the official portals (vlaanderen.be/mijn-verbouwpremie, energie.wallonie.be or homegrade.brussels and your municipality's premiums).
Comparing quotes without surprises
Ask for at least two or three quotes after a site visit and compare them line by line. A heat pump quote that looks cheap sometimes leaves out the cylinder, three-phase or the radiators.
- Ask for a heat-loss or capacity calculation, not an estimate per m².
- Have the quote state the assumed flow temperature and whether radiators stay.
- Check that cylinder, buffer tank, three-phase, removal of the old boiler and commissioning are included.
- Check the VAT rate and whether the amount includes or excludes VAT.
- Compare the same finish and the same brand level.
For boiler and heating work, Alpha Services Benelux, active since 2014, gives a fixed written quote after a site visit (0485 44 55 12). See also boiler and heating, boiler replacement cost or heat pump cost.
Fixed quote after a site visit
Alpha Services Benelux does the work with its own team, active since 2014. VAT BE 0541.320.178.
Request a quoteFrequently asked questions
How much does a heat pump cost in a Belgian renovation?
For an installed air-to-water heat pump the sources give roughly €5,000 to €20,000. Units up to 8 kW run about €7,250–10,000, from 8 kW about €11,750–15,000. Capacity, brand and finish level decide where you land.
Can a heat pump work with my existing radiators?
Yes, if the house stays comfortable at a flow temperature of about 50 °C. Radiators needing 70 °C lower efficiency. Have a professional assess it; low-temperature radiators may add to the budget.
Does a heat pump make sense in a poorly insulated house?
Possibly, but the unit must be larger and uses more electricity. Insulating first or choosing a hybrid system (€5,000–16,000; note: not eligible for the 6% rate) is often wiser. Have the capacity calculated before deciding.
How much cheaper is a heat pump to run than gas?
Comparison sites quote €800–1,200 a year for a heat pump and €2,000–2,600 for a gas boiler. Actual savings depend on insulation, flow temperature and tariffs. Payback: 7 to 12 years, or 5 to 15 years according to other sources.
What VAT applies to a heat pump and a gas boiler?
In a home older than 10 years a heat pump is at 6%; since 1 January 2026 that rate has been extended for five years, also covering newer homes and new builds. Since July 2025, a new gas boiler (supply and installation) is at 21%, even in homes older than 10 years. Hybrid heat pumps are excluded from the 6% measure: ask which rate the quote applies.
Sources
- Prijs warmtepomp 2026: kosten, premies, terugverdientijd — Energiebewust Ontwerpen
- Warmtepomp prijs 2026: compleet overzicht per type — Solarnation
- Warmtepomp of gasketel? vergelijking 2026: kosten, rendement — Zen Zonne-energie
- Prix d'une pompe à chaleur pour une habitation existante (2026) — Luminus (Lumiworld)
- Wat kost een condensatieketel? 2026 Prijzenoverzicht — Homedeal
- Pompe à chaleur en Belgique : prix 2026 — Bobex
- Rendement warmtepomp 2026 — AVS Service
- Wanneer en hoe krijg je verminderd btw-tarief van 6% voor werken aan je woning? — Test-Aankoop
- BTW voor fossiele verwarmingsinstallaties van 6% naar 21% — Vinduwaannemer.be (verwijst naar circulaire 2025/C/47)
- Circulaire 2026/C/19 betreffende de herinvoering van een verlaagd btw-tarief voor de levering met plaatsing van warmtepompen — OECCBB (FOD Financiën, circulaire 2026/C/19)