Air-to-air heat pumps: heating with air conditioning
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An air-to-air heat pump is an air conditioner with a heating function. It transfers heat from outdoor air directly into a room through an indoor unit, without radiators or heating-water pipework.
Winter output and the layout of your rooms decide whether it suits you. One unit in the living room does not guarantee warmth in closed bedrooms. The standard systems below do not heat water for the bathroom.
See exact systems with installation
How an air conditioner heats
In heating mode, the outdoor unit extracts heat from the air. The refrigerant circuit carries it indoors, and the indoor unit's fan distributes the warmed air around the room. Electricity drives the compressor and fans.
Air-to-air can therefore heat a space without a water-based heating system, and cool it in summer. If you want to heat water for radiators, underfloor heating and a cylinder, you need a different system: an air-to-water heat pump.
Arrange hot water for showering separately. A heating function on an ordinary air conditioner does not mean it also has a hot-water cylinder.
One room and several rooms
One indoor and one outdoor unit
This arrangement is called a single split. It mainly heats the room containing the indoor unit. In an open-plan space the air can flow further; with corridors and closed doors, do not rely on the same temperature in every room.
Several indoor units
A multisplit connects several indoor units to one outdoor unit. It lets you control individual rooms, but the outdoor unit's output is shared when they run at the same time. The sum of the numbers on the indoor units is therefore not a guaranteed output for the whole system.
The difference between single split and multisplit is explained by Daikin's Perfera overview. Technical data for specific systems must be checked separately.
Winter output, defrosting and comfort
A cooling-output figure does not tell you how much heat the unit delivers in freezing weather. For year-round heating, ask for documented heating output at the winter temperature in your area and compare it with the rooms' heat loss.
- Operating range: the limit at which the unit still runs, not a promise of full output.
- Defrosting: the unit has to clear frost from the outdoor heat exchanger. Heat delivery to the room may stop during this cycle.
- Comfort: when positioning the unit, take into account the airflow and the noise at the fan speeds needed for heating.
The causes of frost and automatic defrosting are described by Daikin. How often and how long it happens depends on the unit and the weather.
Efficiency and electricity use
COP is the ratio of heat delivered to electricity used at one test point. SCOP is a seasonal ratio based on a standardised pattern of weather and load. Compare the same climate zone and the exact combination of units.
| Figure | FTXM25A + RXM25A | FTXM35A + RXM35A |
|---|---|---|
| Nominal heating output | 2.8 kW | 4 kW |
| COP at the nominal point | 5 | 4.55 |
| SCOP, average climate | 5.2 | 5.2 |
Source: Daikin, Slovak Perfera profile ECPSK24-008A, page 10 (PDF), checked 20 October 2026. Nominal output and COP: outdoors 7 °C dry bulb / 6 °C wet bulb, indoors 20 °C, 5 m of pipe, 0 m height difference. SCOP applies to the average climate zone. These figures do not belong to the Sensira systems in the price list below or to multisplit combinations.
SCOP does not tell you how much electricity a house needs unless you know its heat demand. As a rough estimate: electricity for heating ≈ heat delivered ÷ seasonal factor. Costs then follow from that consumption and your price per kWh.
The actual seasonal factor may differ from the label SCOP. Weather, the set temperature, defrosting and supplementary heating all affect the result. Count hot water and summer cooling separately; without these inputs we do not give a monthly bill or a payback period.
Dated prices for exact systems with installation
The examples are sorted from the lowest price. Each offer covers specific units and a limited installation scope, not automatically heating for a whole house. Prices include VAT and are before any subsidy. They are not a market average or a quality ranking.
| Exact system | Price | Note and source |
|---|---|---|
| Daikin FTXF35F + RXF35F · 1 indoor unit | €1,189including VAT | Installation in standard conditions: 3 m of pipework, electrical cable and condensate drain, one penetration through soft masonry, a bracket and user instruction. Scaffolding, a lifting platform and work on a pitched roof are extra. Confirm the area covered with the firm.iKlimatizacie, checked 20 October 2026 |
| Daikin FTXF35F + RXF35F · 1 indoor unit | €1,269.95including VAT | 3 m of pipework and condensate drain, 5 m of electrical cable, a bracket, one penetration up to 25 cm and commissioning. Travel: Bratislava I–V, Malacky, Pezinok, Senec and the Šamorín area; elsewhere by agreement. Longer runs and additional or reinforced-concrete penetrations are extra.Energion, checked 20 October 2026 |
| Sinclair MV-E14BI2 + 2× SIH-09BIK · 2 indoor units | €2,049including VAT | 6 m of lines, two penetrations through soft masonry, a bracket and user instruction. Longer lines and non-standard work are extra; confirm the area covered. The output designations in the name and the seller's specifications do not match, so we do not derive heating output from them.iKlimatizacie, checked 20 October 2026 |
| Hisense 2AMW50U4 + HB25XU0AG + HB35XU0AG · 2 indoor units | €2,437including VAT | 6 m of lines, two penetrations through soft masonry, a bracket and user instruction. Longer lines, concrete and core drilling, chasing and work at height are extra. Confirm the area covered with the firm.iKlimatizacie, checked 20 October 2026 |
| Sinclair MV-E21BI2 + 3× SIH-09BIR · 3 indoor units | €3,083including VAT | 9 m of lines, three penetrations through soft masonry, a bracket and user instruction. Longer lines and non-standard work are extra. Confirm the area covered with the firm.iKlimatizacie, checked 20 October 2026 |
| Hisense 3AMW62U4 + 3× HB25XU0AG · 3 indoor units | €3,271including VAT | 9 m of lines, three penetrations through soft masonry, a bracket and user instruction. Availability on request; longer lines and non-standard work are extra. Confirm the area covered with the firm.iKlimatizacie, checked 20 October 2026 |
The line length is the package's limit; have the split of routes between the units confirmed. Promotional prices and availability must be confirmed by the seller. We do not derive winter heating output from the output numbers in the offers' names.
When comparing, ask for a site survey and a breakdown of the electrical supply, wall penetrations, lines, condensate drains and access to the outdoor unit. A difference in the scope of work can matter more than a difference in the price of the equipment itself.
Subsidy: your existing heating matters too
Air-to-air only without a water-based heating system
According to SIEA, this type is supported only in a property without a water-based heating system. If you have radiators or underfloor heating with a water circuit, adding an air conditioner does not by itself meet the condition.
A heating function alone does not create entitlement. The exact model must be checked in the list of equipment, along with the household and the other conditions. We do not automatically assign a subsidy to any system in the table.
Heat-pump subsidy conditions and procedureNew applications cannot be registered at the moment. Status according to SIEA's applications page, checked 20 October 2026. Check current availability of support before ordering.
Common questions
Will one unit heat a whole house?
That is not guaranteed. Heat loss and the path the air takes to each room decide it. Closed rooms need their own solution; the design must also cover the bathroom and corridors.
How does it heat at low temperatures?
That depends on the specific model and conditions. You need its heating output at the winter design temperature, not just its minimum operating temperature. The design must also include defrosting and any supplementary heat source.
Can I get a subsidy if I have radiators?
If they are part of a water-based heating system, an air-to-air system does not meet the programme condition above. Do not confuse it with the rules for air-to-water. SIEA assesses eligibility in each case.
Does an air conditioner also heat water for showering?
The standard single-split and multisplit systems on this page heat air, not domestic hot water. That needs to be provided separately.
Comparing heat-pump types
- Air-to-water
- Takes heat from outdoor air and heats water for radiators or underfloor heating, as well as domestic hot water.
- Ground-source
- Extracts heat from the ground through a borehole or garden collector. Ground works make up a substantial part of the cost.
- Water-source
- Extracts heat from groundwater in wells. It needs enough suitable water and the relevant permissions.
Sources
The technical examples come from manufacturer documentation; the prices come from installers' offers, with a link and date on each row. They are not our measurements or individual quotations. We are an independent information site; we do not sell or install equipment. These links are not affiliate links.
- Daikin Perfera, page 10 (PDF) — exact combinations and test conditions.
- Daikin: frost and defrosting — explanation of winter operation.
- SIEA: supported equipment — the air-to-air restriction.
- SIEA: applications — registration availability, checked 20 October 2026.