Comparison · 10 min read · Updated 2026-05-11
2026 heat-pump efficiency by type across Europe: air-to-water, air-to-air and ground-source
A data-led comparison of how heat-pump efficiency varies by technology type across Europe, using current EPREL and market data to show which systems deliver the best seasonal performance and where the gaps are largest.
Europe’s 2026 efficiency hierarchy by heat-pump type
The current European sample in the live EPREL catalog contains 60,989 listed heat-pump models from 777 manufacturers (market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). Within that stock, the type mix is heavily skewed toward air-based systems.
By model count, air-to-water dominates with 30,452 listings, equal to 49.9% of all models (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). Air-to-air follows with 21,065 listings, or 34.5% (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). Heat-pump water heaters account for 9,228 listings, or 15.1% (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). Ground-water systems are a niche at 213 listings, or 0.35%, while water-water systems are smaller still at 31 listings, or 0.05% (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API).
That model distribution matters because the registry’s overall average SCOP is 4.55 (market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API), and the types with recorded SCOP sit around or above that level. Among types where the corpus actually reports an average SCOP, water-water leads at 6.15 (type_efficiency / EPREL Public API · type aggregation), followed by ground-water at 4.77 (type_efficiency / EPREL Public API · type aggregation), then air-water at 4.54 (type_efficiency / EPREL Public API · type aggregation).
For air-air and heat-pump water heaters, the registry sample supplied here does not record an average SCOP. That is a registry-data limitation in this corpus, not evidence that those systems are inefficient. Readers who want the current product universe by segment can filter the catalog by air-to-water type, air-to-air type, or browse the full market index snapshot.
Type ranking in the current sample
| Heat-pump type | Models | Share of total | Average SCOP | Average capacity | Average outdoor noise |
|---|---|---|---|---|---|
| water-water | 31 | 0.05% | 6.15 | 35.65 kW | 42.0 dB |
| ground-water | 213 | 0.35% | 4.77 | 18.45 kW | 58.8 dB |
| air-water | 30,452 | 49.9% | 4.54 | 11.83 kW | 59.8 dB |
| air-air | 21,065 | 34.5% | not recorded | 5.41 kW | 64.1 dB |
| hp-water-heater | 9,228 | 15.1% | not recorded | not recorded | not recorded |
(type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API)
How much the average SCOP differs across air-to-water, air-to-air and ground-source
The cleanest comparison the dataset allows is between air-water, ground-water and water-water, because those are the types with reported average SCOP values.
Water-water’s average SCOP of 6.15 sits 1.61 points above air-water’s 4.54 (type_efficiency / EPREL Public API · type aggregation). Expressed relative to the lowest recorded type, that is a 35.5% higher average SCOP for water-water versus air-water (type_efficiency / EPREL Public API · type aggregation). Against ground-water, water-water is ahead by 1.38 SCOP points, or 28.9% (type_efficiency / EPREL Public API · type aggregation). Ground-water, in turn, is 0.23 points above air-water, or 5.1% (type_efficiency / EPREL Public API · type aggregation).
So the broad hierarchy is straightforward: water-water is well ahead, ground-water is modestly ahead of air-water, and air-water sits close to the market-wide average of 4.55 (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API).
But the size of the type buckets is just as important as the averages. Water-water leads on efficiency with only 31 listed models, while air-water sits near the market mean across 30,452 models (type_efficiency / EPREL Public API · type aggregation). That suggests that “best average type” and “best chance of finding a suitable product” are different questions. A buyer choosing between technology classes is comparing thermodynamic potential; a buyer choosing an actual unit is comparing the products available in their size, sound and installation constraints. That distinction is visible throughout the top SCOP leaderboard and the methodology notes, and it is one reason average type performance should not be read as a shortcut for model-level due diligence.
Air-air cannot be placed in the same SCOP ranking because the supplied EPREL aggregation does not record an average SCOP for that type (type_efficiency / EPREL Public API · type aggregation). The same applies to heat-pump water heaters.
Where the best models sit: the top SCOP performers by technology class
At the very top of the current EPREL ranking, the single highest-SCOP model in the supplied leaderboard is the Risch Kälte- und Klimatechnik GmbH OH I 4esr TWW W/W, listed as air-water, with a SCOP of 7.0 (top_models / EPREL Public API via Househeating Pulse catalog).
Among the top 15 models by SCOP overall, 11 are air-water and 4 are water-water (top_models / EPREL Public API via Househeating Pulse catalog). Ground-water contributes none of the top 15 overall in this particular ranking slice, despite having a higher average SCOP than air-water (top_models / EPREL Public API via Househeating Pulse catalog; type_efficiency / EPREL Public API · type aggregation). That is one of the clearest signs that “average by type” and “top-end leaderboard presence” are not the same thing.
The highest-ranked water-water model in the overall list is the Waterkotte GmbH CTC EcoTouch 525 (water/water) at 6.97 SCOP, tied on value with the Hoval Aktiengesellschaft 42 -Thermalia® twin (26) GW and the Waterkotte GmbH EcoTouch DS 5034.5 T (water/water) (top_models / EPREL Public API via Househeating Pulse catalog).
Within the air-water leaderboard alone, the top 15 entries range from 7.0 down to 6.8 SCOP (top_models / EPREL Public API via Househeating Pulse catalog). Within the ground-water leaderboard, the top 15 range from 5.97 down to 5.4 SCOP (top_models / EPREL Public API via Househeating Pulse catalog). The highest ground-water entry therefore trails the best air-water entry by 1.03 SCOP points, or 17.3% (top_models / EPREL Public API via Househeating Pulse catalog).
That sounds counterintuitive against the type averages, but the leaderboard sample is enough to show why the editorial angle matters: the current product mix inside each category can outweigh the headline technology label. Readers can inspect the air-to-water top SCOP table and the ground-source top SCOP table directly.
The air-air top-SCOP leaderboard supplied here is empty, so this corpus cannot say how many of the market’s leading SCOP performers come from air-air (top_models / EPREL Public API via Househeating Pulse catalog). The registry slice provided simply does not record them.
Efficiency versus trade-offs: capacity and noise by type
On average capacity, water-water again stands apart at 35.65 kW (type_efficiency / EPREL Public API · type aggregation). Ground-water averages 18.45 kW, air-water 11.83 kW, and air-air 5.41 kW (type_efficiency / EPREL Public API · type aggregation). Relative to air-water, water-water’s average capacity is 23.82 kW higher, or 201.4% higher; ground-water’s is 6.62 kW higher, or 56.0% higher; and air-air’s is 6.42 kW lower, or 54.3% lower (type_efficiency / EPREL Public API · type aggregation).
On outdoor noise, water-water is also the quietest recorded type at 42.0 dB, compared with 58.8 dB for ground-water, 59.8 dB for air-water, and 64.1 dB for air-air (type_efficiency / EPREL Public API · type aggregation). That means water-water averages 17.8 dB lower than air-water and 22.1 dB lower than air-air (type_efficiency / EPREL Public API · type aggregation).
By the numbers in this sample, water-water is the only type that combines the highest average efficiency, the highest average capacity and the lowest average outdoor noise: 6.15 SCOP, 35.65 kW and 42.0 dB (type_efficiency / EPREL Public API · type aggregation). The caveat is scale: those figures come from just 31 models (type_efficiency / EPREL Public API · type aggregation). Buyers weighing acoustic constraints should compare these averages with the model-level quietest heat-pump leaderboard, because type averages do not tell the whole siting story.
What the model mix tells us about whether type or product selection drives performance
The current EPREL spread suggests that technology class explains part of the efficiency hierarchy, but product mix explains a great deal of what buyers will actually encounter.
The evidence for a genuine type effect is strong enough. Water-water averages 6.15 SCOP across its category, well above ground-water at 4.77 and air-water at 4.54 (type_efficiency / EPREL Public API · type aggregation). Ground-water also beats air-water on average by 0.23 points (type_efficiency / EPREL Public API · type aggregation). So the class signal is real.
But the evidence for product-mix distortion is just as clear. Air-water makes up nearly half of all listed models at 49.9%, while ground-water and water-water together account for only 244 models, or 0.40% of the full catalog (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). Despite that, air-water captures 11 of the top 15 SCOP positions overall, or 73.3%, while water-water captures the remaining 4, or 26.7% (top_models / EPREL Public API via Househeating Pulse catalog).
That is a classic sign of breadth. The largest category may not have the best average, but it has far more chances to place extreme outliers near the top of the table. Buyers looking at the full manufacturer roster can see the same scale effect at brand level: Daikin Europe N.V. alone accounts for 14,668 models, or 24.05% of the total, while Mitsubishi Electric Europe B.V. has 5,575 models, or 9.14%, and Bosch Thermotechnik GmbH has 3,602, or 5.91% (market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). Big catalogs produce both average performers and edge-case standouts.
There is also a coverage issue. The supplied corpus does not report average SCOP for air-air, even though air-air makes up 34.5% of all listings (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). So any “Europe-wide type ranking” is necessarily partial unless and until EPREL outputs are normalised across all categories. For background on the underlying registry, see the EU’s EPREL portal and product-labelling framework.
What buyers and installers should infer from the current EPREL spread
The practical reading of the 2026 sample is not simply “ground-source wins”. The more accurate statement is narrower.
First, among types with reported SCOP averages, water-water is the clear leader at 6.15, ground-water is second at 4.77, and air-water is third at 4.54 (type_efficiency / EPREL Public API · type aggregation). Second, the efficiency gap between the best and worst recorded type is large: 1.61 SCOP points, or 35.5% from water-water to air-water (type_efficiency / EPREL Public API · type aggregation). Third, the most efficient average type is also the rarest serious category in the sample, with only 31 models (type_efficiency / EPREL Public API · type aggregation).
For most European buyers, that means the installed reality is still likely to be found inside the very large air-water market, not the tiny water-water pool. Air-water represents 30,452 listings and nearly half the catalog (type_efficiency / EPREL Public API · type aggregation; market_index_snapshot / Househeating Pulse · Market Index v1, computed from EPREL Public API). So even if its category average is lower, its available product spread is far broader. That is why installers should benchmark individual units, not rely on type averages alone, especially for capacity, siting noise and climate fit. The sizing calculator, payback calculator and climate-fit tool are more useful for a real shortlist than a generic type label.
The final caution is about missing data. This corpus does not provide an average SCOP for air-air or heat-pump water heaters, and it does not explain why several top-ranked products show outdoor noise as 0 dB; the registry slice supplied here simply records those values as listed (type_efficiency / EPREL Public API · type aggregation; top_models / EPREL Public API via Househeating Pulse catalog). For buyers, that means the safest workflow is to use the type averages as a market map, then verify each candidate model page and manufacturer profile individually.
Sources
- EPREL Public API · type aggregation — snapshot 2026-05-11
- Househeating Pulse · Market Index v1, computed from EPREL Public API — snapshot 2026-05-11
- EPREL Public API via Househeating Pulse catalog — snapshot 2026-05-11
Continue reading
- How to compare SCOP, SEER and energy class on EPREL — A practical guide to reading heat-pump efficiency labels without mixing heating and cooling metrics.
- How to size a heat pump before you shortlist models — Why capacity bands matter as much as headline efficiency when choosing between product types.
- How to compare heat-pump noise ratings in EPREL — What outdoor sound figures do and do not tell you about real installation noise.
- How to use EPREL to shortlist heat pumps in Europe — A step-by-step workflow for moving from registry data to a realistic buyer shortlist.