Water-to-water heat pumps (groundwater)
Use groundwater or surface water as the source (open system with an extraction and a return well). The most efficient type, but only possible with suitable ground conditions and a permit.
100 models in our database meet this; below the first 25 in order.
Criteria:
- Type (source): Water-to-water
- Sorted by: SCOP (35 °C) (highest first)
Only models for which these figures are known. This is a ranking by data, not a test or recommendation; the source of every value is on the product page.
More selections
- Quietest 4–6 kW heat pumps
- Most efficient 4–6 kW heat pumps
- Quietest 6–8 kW heat pumps
- Most efficient 6–8 kW heat pumps
- Quietest 8–10 kW heat pumps
- Most efficient 8–10 kW heat pumps
- Quietest 10–14 kW heat pumps
- Most efficient 10–14 kW heat pumps
- Heat pumps with R290 (propane)
- Most efficient heat pumps for radiators (55 °C)
- Air-to-water heat pumps
- Ground-source heat pumps (brine-to-water)
- Hybrid heat pumps (with a gas boiler)
Sources
- List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 28 Sept 2026