Air-to-air or air-to-water heat pump in Belgium: differences, cost and which suits your home
Short answer: An air-to-air heat pump (an air conditioner with heating) costs about €2,500–7,000 installed in Belgium (AVS Service), heats rooms through indoor units and makes no hot water. An air-to-water heat pump costs about €8,000–17,000 (AVS Service), heats the whole house through radiators or underfloor heating and supplies domestic hot water. In 2026 both generally qualify for 6% VAT (air-to-air only under conditions).
Prices in this article are indicative Belgian market ranges, not Alpha Services Benelux's price list. Your fixed price is in the quote.
What is the difference between air-to-air and air-to-water?
Air-to-air blows warm or cool air straight into the room; air-to-water heats the water in your central heating. That one difference decides price, comfort and what you can replace.
An air-to-air heat pump is technically a reversible split air conditioner: one outdoor unit and one or more indoor units. In winter it takes heat from outdoor air, in summer it cools. There is no water circuit, so no radiators and no hot water. If you wonder about heat pump versus AC: an air conditioner with a heating function is an air-to-air heat pump.
An air-to-water heat pump takes over the boiler’s job. It heats water for radiators or underfloor heating and usually a cylinder for domestic hot water, so a renovation brings plumbing work too.
| Feature | Air-to-air | Air-to-water |
|---|---|---|
| Heats | Room by room | Whole home |
| Hot water | No | Yes, with a cylinder |
| Emitters | Indoor units (air) | Radiators or underfloor heating |
| Cooling | Yes, as standard | Reversible models only, limited effect |
| Efficiency (SCOP) | 3.5 to 5 | 3 to 4.5 |
| Outdoor unit noise | 40–55 dB(A) at 3 m | 35–55 dB(A) at 3 m |
What does an air-to-air or air-to-water heat pump cost?
Expect roughly €2,500–7,000 for air-to-air and €8,000–17,000 for air-to-water (AVS Service), installation included. Sources differ: Facq quotes about €2,000 for a single-split and €8,000–18,000 for air-to-water, installation-pompe-chaleur.be €5,000–12,000 for air-to-air (incl. 6% VAT), Trustup €3,000–8,000 and €8,000–18,000 (incl. 6% VAT). It depends on output, number of indoor units and the state of your home.
| System | Typical price |
|---|---|
| Air-to-air, 1 indoor unit (mono-split) | €2,500–5,000 |
| Air-to-air, 2 indoor units | €5,000–6,000 |
| Air-to-air, 3 indoor units | €6,000–7,000 |
| Air-to-water monobloc | €8,000–12,000 |
| Air-to-water split | €10,000–15,000 |
| Hybrid (with existing boiler) | €7,000–11,000 |
| Air-to-water all-electric with cylinder | €13,000–17,000 |
These are market ranges, not the price list of Alpha Services Benelux. More on air-to-water in our heat pump cost guide.
What drives the price?
For air-to-air the number of indoor units matters most; for air-to-water it is the system type and what has to change around the heat pump.
- Output and number of indoor units: every extra indoor unit adds piping and a device.
- Air-to-water type: monobloc, split, hybrid or all-electric, see the table above.
- Emitters: existing radiators must give enough heat at 35–45 °C. If not, they are replaced or you choose a hybrid system.
- Electrical installation: a three-phase supply or an adapted fuse box may be needed.
- Pipework and position: long pipe runs, wall drilling or a roof-mounted outdoor unit cost extra.
| Item | Market range |
|---|---|
| Installation and commissioning, air-to-water | about €2,000 |
| Three-phase electricity | €500–1,500 |
| Underfloor heating (if new) | €40–70 per m² |
| Wall drilling (air-to-air) | €150–400 |
| Yearly servicing, air-to-air | €90–150 |
For floor heating, see the underfloor heating cost per m² guide.
What does each system use and cost per year?
An air-to-air heat pump uses about 800–1,500 kWh a year for one or two indoor units; an air-to-water heat pump 3,000–5,000 kWh a year for a whole home. A gas boiler uses about 17,000 kWh of gas for the same home (AVS Service).
The sources give kWh rather than fixed euro amounts, because the cost depends on your electricity tariff, insulation and habits. Multiply the consumption by the rate on your own energy bill for a realistic figure. Solar panels or a day/night tariff lower the cost.
Compare carefully: air-to-air often heats only part of the house, so its low consumption says little about the total. Air-to-water covers heating and hot water, which is why it uses more. In extreme cold (below roughly -10 °C) air-to-air efficiency drops; if it is your main heating, choose a cold-climate model.
Noise and placement of the outdoor unit
Place the outdoor unit at least 3 m from bedroom windows, on a vibration-free base with free airflow. That is the installers’ rule of thumb (AVS Service); the unit itself produces 35–55 dB(A) at 3 m.
Flanders sets no fixed distance for a domestic heat pump, but its code of good practice (Departement Omgeving) gives guideline values of 45 dB(A) by day (7–22 h) and 40 dB(A) at night (22–7 h) at the plot boundary. It is not law, but it is used in neighbour disputes. Municipalities can, however, adopt them in local rules. The Departement Omgeving stresses that location and choice of unit are decisive.
- Each doubling of distance cuts noise by about 6 dB; against a wall expect about 3 dB more, in a corner about 6 dB.
- In Flanders a domestic outdoor unit usually needs no permit, and according to the Departement Omgeving it is exempt if it stands at least 2 m from the plot boundary, is fixed to the side or rear façade, or sits on the (flat) roof. Local rules can differ.
- Brussels and Wallonia have their own rules: ask your municipality.
Have a professional assess the position before you choose a unit. Installing a unit that contains F-gases must be done by a certified refrigeration technician.
Which one suits which home?
Air-to-water suits a home where you replace the boiler and heat everything; air-to-air suits flats, extensions, single rooms, or anyone who also wants cooling.
- Air-to-water: well-insulated home (ideally E-level ≤ 70), underfloor heating or low-temperature radiators, enough electrical capacity. With average insulation, a hybrid system is an option.
- Air-to-air: small to mid-sized well-insulated homes (up to about 150 m²), homes without central heating, flats, rentals, extensions and attic rooms.
- Both: air-to-water for base heating and hot water, air-to-air in a room that overheats in summer.
Poorly insulated? Read whether to insulate first. For boiler replacement, see our boiler and heating page.
6% VAT and grants: what to know
In 2026 a heat pump fitted by a professional (a VAT-registered contractor) in a private home generally qualifies for 6% VAT. For homes at least 10 years old the renovation rate applies with no end date; for newer homes a temporary rate applies to VAT becoming due between 1 January 2026 and 31 December 2030, and the unit must carry an EU energy label (VCN). Hybrid heat pumps in newer homes stay at 21%. In homes at least 10 years old a hybrid is split: 65% at 6% and 35% (the fossil part) at 21% (FPS Finance, circular 2025/C/47; summarised by VCN). An air-to-air unit only gets 6% if its heating function cannot be permanently disabled. A unit you buy yourself stays at 21%, even if an installer fits it later; only supply + installation by the same professional gets 6% (circular 2026/C/19).
Grants differ by region and change often. Check the conditions at vlaanderen.be (Mijn VerbouwPremie), homegrade.brussels (and your municipality) and wallonie.be, and have the VAT rate stated on the quote.
Comparing quotes: what to check
Compare what each quote includes, not just the total. Quotes of €9,000 and €12,000 can cover very different work.
- Is your home’s heat loss calculated, or estimated from floor area?
- Are radiators checked or replaced, and is it included?
- Is the cylinder or buffer tank included, and what size?
- Who handles the electrical upgrade (phases, fuse box)? Electrical work must be AREI-compliant.
- Where does the outdoor unit go, and what is its sound power?
- Is the VAT rate stated, and are commissioning and servicing included?
Alpha Services Benelux has been active since 2014 and works with its own team in heating, plumbing and electrical. You get a fixed written quote after a site visit. Use the renovation calculator for a first idea or see the renovation page. Call or WhatsApp 0485 44 55 12, or email [email protected].
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
What is the difference between an air-to-air and an air-to-water heat pump?
Air-to-air heats (and cools) the air in separate rooms through indoor units and makes no hot water. Air-to-water heats the water for radiators or underfloor heating and usually domestic hot water too, so it can replace the boiler.
Is a heat pump the same as an air conditioner?
An air conditioner with a heating function is an air-to-air heat pump: same technology, reversible. An air-to-water heat pump is different: it feeds a water circuit and replaces central heating, not just a room unit.
How much does an air-to-air heat pump cost installed in Belgium?
According to AVS Service about €2,500–5,000 for one indoor unit and €5,000–7,000 for two or three. Other sources quote €3,000–8,000 (Trustup, incl. 6% VAT) or €5,000–12,000 (installation-pompe-chaleur.be, incl. 6% VAT). The number of indoor units matters most.
Can an air-to-air heat pump heat my whole house?
Only with several indoor units and a separate system for hot water, and comfort is less even. It suits small, well-insulated homes up to about 150 m². For a whole house with hot water, air-to-water usually makes more sense.
Do I need a permit for the outdoor unit?
In Flanders usually not for a domestic unit, and the Departement Omgeving says it is exempt if it stands at least 2 m from the plot boundary, is fixed to the side or rear façade, or sits on the (flat) roof. Local rules can differ, and Brussels and Wallonia have their own rules. Check with your municipality.
What VAT rate applies to a heat pump in 2026?
Generally 6% for a heat pump fitted by a professional in a private home, including air-to-air if the heating cannot be permanently disabled. Hybrid heat pumps in newer homes stay at 21%; in homes at least 10 years old a hybrid is split: 65% at 6% and 35% (the fossil part) at 21% (FPS Finance, circular 2025/C/47). Have the rate stated on the quote.
Sources
- Air-to-air or air-to-water heat pump: which solution is right for your project? — Facq
- Lucht-lucht warmtepomp 2026: prijs, werking & airco — AVS Service
- Lucht-water warmtepomp 2026: prijs, werking & premie — AVS Service
- Prix pompe à chaleur en Belgique (2026) — Trustup
- Prix pompe à chaleur 2026 : combien coûte une PAC en Belgique ? — installation-pompe-chaleur.be
- Circulaire 2026/C/19 betreffende de herinvoering van een verlaagd btw-tarief voor de levering met plaatsing van warmtepompen — FOD Financiën, Algemene Administratie van de Fiscaliteit (circular of 20.01.2026, text republished by OECCBB)
- Circulaire 2025/C/47 betreffende het toepasselijk btw-tarief voor de levering met plaatsing van een centrale verwarmingsinstallatie die werkt op fossiele brandstoffen bij renovatie of afbraak en heropbouw — FOD Financiën, Algemene Administratie van de Fiscaliteit (circular of 28.07.2025, text republished by Forum for the Future)
- VAT heat pump Belgium 2026: 6% vs 21% gas boiler — VCN
- Plaats de juiste warmtepomp op de juiste plek om geluidsoverlast te voorkomen — Departement Omgeving, Vlaanderen
- Omgevingsaspecten bij warmtepompen en airco's (Izegem, 14/10/2025) — Departement Omgeving (presentation hosted by Provincie West-Vlaanderen)