Air-to-Water Heat Pump – An Efficient Solution for Hydronic Heating

Everything you need to know about air-to-water heat pumps

An air-to-water heat pump (ASHP-W) is an efficient solution for hydronic heating systems. It harnesses thermal energy from the outdoor air and transfers it to hydronic heating — radiators, underfloor heating, or domestic hot water. On this page, we cover how an air-to-water heat pump works, who it is for, what it costs, and how the installation proceeds.

Why choose an air-to-water heat pump?

• **Significant savings** — Up to 40–60% lower heating costs compared to electric or oil heating
• **Compatible with existing systems** — Connects directly to hydronic radiator or underfloor heating
• **No drilling required** — Unlike ground source heating, an ASHP-W does not require borehole drilling
• **Domestic hot water** — The same system also heats your domestic hot water
• **Environmentally friendly** — A solution that utilises renewable energy and reduces your carbon footprint

How does an air-to-water heat pump work?

An air-to-water heat pump works by collecting thermal energy from the outdoor air. The outdoor unit extracts heat from the outside air — even at sub-zero temperatures — and the compressor raises the temperature sufficiently for hydronic heating. The heat is transferred via a heat exchanger to water, which circulates through radiators, underfloor heating, or a hot water cylinder. The system works efficiently alongside the existing heating system — for example, during severe frost an electric element or oil boiler can provide backup heating.

Air-to-water heat pump price 2026

The price of an air-to-water heat pump depends on the property size, heating requirements, and scope of installation. Typical prices in the Helsinki metropolitan area:

• **Small detached house (80–120 m²):** €8,000–€11,000 — 5–8 kW output, hydronic heating and domestic hot water
• **Medium-sized house (120–180 m²):** €11,000–€15,000 — 8–12 kW output, underfloor or radiator heating
• **Large property (180+ m²):** €15,000–€18,000 — 12–16 kW output, hybrid system possible

Air-to-water heat pump price — further information

Prices include the equipment, installation, and commissioning. The exact price depends on the specific characteristics of the property — always request a property-specific quote. Read our comprehensive guide to air-to-water heat pump pricing and operation.

Air-to-water heat pump vs. ground source heat pump — which is better?

Ground source heating offers the lowest running costs and the best efficiency ratio, but requires a more expensive initial investment (borehole). An air-to-water heat pump is cheaper to install, does not require drilling, and is suitable for plots where a borehole is not possible. The efficiency ratio of an ASHP-W drops slightly in severe frost, but a modern unit performs well even at -25°C. If your budget is limited or you do not want drilling work, an air-to-water heat pump is a sensible choice. If you are looking for the lowest possible running costs and a long-lasting solution, ground source heating is worth considering.

Air-to-water heat pump vs. air source heat pump

An air source heat pump heats indoor air directly by blowing — it is an affordable supplementary heating solution but does not replace a hydronic heating system. An air-to-water heat pump, on the other hand, heats the entire hydronic system and domestic hot water, and can serve as the property’s primary heating source. If you have hydronic radiator or underfloor heating, an ASHP-W is the more effective solution. If you only need supplementary heating for a single room, an air source heat pump will suffice.

Air-to-water heat pump installation — how the project proceeds

Kevyt Remppa delivers air-to-water heat pump installation as a turnkey service:

• **Survey** — We assess the property’s heating requirements and the existing system
• **Energy calculations** — We calculate the required output and estimated savings
• **Unit selection** — We select the right air-to-water heat pump for the property
• **Quote** — You receive a clear quote with the equipment and installation itemised
• **Installation** — Outdoor and indoor unit installation, pipework, and connections
• **Commissioning** — Settings optimisation and guidance on using the unit
• **Follow-up** — If needed, we monitor performance and adjust settings

Air-to-water heat pump household tax deduction

The installation work for an air-to-water heat pump qualifies for the Finnish household tax deduction (kotitalousvähennys). In 2026, the deduction is 35% of the labour cost, up to €1,600 per person per year (€150 excess). For a couple, the combined maximum deduction is €3,200. We itemise the labour and material costs in the quote so you can easily claim the deduction. Learn more about the household tax deduction calculator.

Air-to-water heat pump as a replacement for oil heating

An air-to-water heat pump is an excellent choice when you want to move away from oil heating. An ASHP-W can be connected directly to the existing hydronic system, allowing the oil boiler to be decommissioned or retained as a backup for the coldest spells. Savings compared to oil heating can reach 50–70% per year. In addition, you eliminate the oil tank and associated maintenance costs.

We operate across the Helsinki metropolitan area

Air-to-water heat pump installation is available from us in Helsinki, Espoo, Vantaa, Kauniainen, Kerava, Järvenpää, and Kirkkonummi. We are familiar with the region’s building stock and heating systems, and know how to select the right equipment for every property.

Learn more about our service areas: Helsinki, Espoo, Vantaa.

Request a free air-to-water heat pump quote

Get in touch and tell us about your property. We carry out a free survey, calculate the energy savings, and prepare a quote. You will receive a clear overview of the investment and expected savings.