Guide

Ground source or an air-to-water heat pump?

Updated

A ground-source pump has a seasonal factor of 3.0 against 2.5 for air-to-water at a 40 °C supply (Ympäristöministeriö, 20 December 2017). Installed, ground source costs €13,000–€33,225 and air-to-water €13,000–€18,000; the sources disagree inside those bands. The choice is decided by the supply temperature, the plot, and whether an oil system is removed.

The efficiency gap widens with the supply temperature

The ministry’s tables give ground source 3.0 and air-to-water 2.5 at a 40 °C supply; at 50 °C they are 2.7 and 2.3. For domestic hot water the gap is widest: 2.3 against 1.8 (Ympäristöministeriö, 20 December 2017). A house on underfloor heating therefore shrinks the difference, while an old radiator network running a high supply temperature magnifies it.

The price bands and what they cover

There is no single installed price for ground source but three, produced by three different methods: €13,000–€20,000 turnkey — the site’s own typical range (urakkamaailma.fi, 14 August 2026). €23,000–€26,000 replacing oil heating, demolition included — 2 costed worked examples (Motiva, 2024). €27,075–€33,225 jobs actually paid for — median of 2 verified jobs (urakkadiili.fi, 13 May 2025). The same picture for air-to-water: €17,000–€18,000 replacing oil heating, demolition included — 2 costed worked examples (Motiva, 2024). €13,100–€13,900 jobs actually paid for — median of 2 verified jobs (urakkadiili.fi, 19 August 2026). €13,000–€16,000 installed — a vendor’s stated range (1komma5.com, 2026).

Drilling, the permit and the plot

A borehole for a detached house is typically drilled to 100–200 m, and 30–50 €/m is the rate repeated for a drilled metre (urakkadiili.fi, 5 February 2025). No authority or research source was found for that rate, so treat it as indicative. Drilling a borehole needs a municipal permit almost everywhere in Finland, and the permit fee is not inside a contractor’s turnkey price unless stated. There is no national permit fee, because every municipality sets its own. An air-to-water pump needs neither a borehole nor a permit, but it does need a place for the outdoor unit, a foundation and a noise level the neighbour can live with.

What actually decides between them

Four things, in this order: the supply temperature of the heat distribution; whether the plot can be drilled and permitted; whether an oil system is being removed, which lifts the household tax credit to 60% (Verohallinto, 10 February 2026); and sizing. A ground-source pump is sized below peak load, so its back-up resistor produces 1–5% of the annual energy (Motiva, 16 February 2026); leave the resistor out of the calculation and the saving is overstated.

Installers that do both

142 installers

Ask for the same house sized for both systems: the supply temperature and the sizing output are the only numbers that make two quotes comparable.

See all: Ground-source heating →

Read on

FAQ

Frequently asked questions

Which one is more efficient?

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Ground source. In the ministry’s tables the seasonal factor is 3.0 against 2.5 at a 40 °C supply and 2.3 against 1.8 for domestic hot water (Ympäristöministeriö, 20 December 2017).

What does ground source cost installed?

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€13,000–€33,225, depending on the source. €13,000–€20,000 turnkey — the site’s own typical range (urakkamaailma.fi, 14 August 2026). €23,000–€26,000 replacing oil heating, demolition included — 2 costed worked examples (Motiva, 2024). €27,075–€33,225 jobs actually paid for — median of 2 verified jobs (urakkadiili.fi, 13 May 2025).

Why do the prices differ so much?

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Because the figures are produced by different methods and cover different things. €27,075–€33,225 jobs actually paid for — median of 2 verified jobs (urakkadiili.fi, 13 May 2025). The median of two jobs. The dearer of them was a 1950s three-storey house whose entire heat distribution network was rebuilt, which lifts the median on its own.

How deep does the borehole need to be?

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Typically 100–200 m for a detached house, with 30–50 €/m the rate repeated per drilled metre (urakkadiili.fi, 5 February 2025). A municipal permit is needed almost everywhere, and its fee is not inside the contract price.

Is the switch worth it in an oil-heated house?

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Giving up oil heating altogether carries an elevated credit of 60% of the labour share, up to €3,500 per person, in force until 31 December 2027 (Verohallinto, 10 February 2026).

Sources

  1. Esimerkkejä öljylämmityksen vaihtamisen kustannuksista (PDF)

    Motiva · 2024 · authority or research

  2. Ground-source heat pump (tietopankki)

    Motiva · 16 February 2026 · authority or research

  3. Kotitalousvähennys verotuksessa (VH/555/00.01.00/2026)

    Verohallinto · 10 February 2026 · authority or research

  4. Kotitalousvähennys asunnon kunnossapito- ja perusparannustöistä sekä öljylämmityksestä luopumisesta aiheutuneista töistä

    Verohallinto · 1 January 2025 · authority or research

  5. Rakennuksen energiankulutuksen ja lämmitystehontarpeen laskenta, taulukot 7.8–7.10

    Ympäristöministeriö · 20 December 2017 · authority or research

  6. Maalämmön asennus — toteutuneet hinnat

    urakkadiili.fi · 13 May 2025 · marketplace or trade press

    The page is titled "realised prices (2026)" but the page itself was last updated on 13 May 2025.

  7. Ilma-vesilämpöpumpun asennus — toteutuneet hinnat

    urakkadiili.fi · 19 August 2026 · marketplace or trade press

  8. Maalämpö — hinta

    urakkamaailma.fi · 14 August 2026 · marketplace or trade press

  9. Ilmavesilämpöpumpun hinta

    1komma5.com · 2026 · vendor

  10. Maalämpökaivon poraus — hinta

    urakkadiili.fi · 5 February 2025 · vendor

    The page is titled 2026 but carries an updated date of 5 February 2025.

Figures verified 3 September 2026