Best 4–6 kW air source heat pumps (2026)
123 models in our database meet this; below the first 25 in order.
Criteria:
- Type (source): Air-to-water
- Rated output 35 °C from 4 up to 6 kW
- Ranking: data score with these weights: SCOP (35 °C) 30 % · SCOP (55 °C) 25 % · Outdoor unit sound power 25 % · Refrigerant GWP 20 %
Air-to-water heat pumps only: ground-source and water-to-water heat pumps reach a higher SCOP thanks to their warmer source, so they cannot be compared fairly with air-to-water units. They have their own selections.
A ranking based on manufacturer and register data, not a test: we have not measured the units ourselves, and price, installation and service are not included. The source of every value is on the product page.
The ranking
ACOND Grandis N
Data score 88/100
- SCOP (35 °C) 5.38: no. 3 of 123 models
- SCOP (55 °C) 4.05: no. 3 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Image: Clivetrequest removal Clivet WiSAN-PMP 1 S 2.1
Data score 85/100
- SCOP (35 °C) 5.23: no. 7 of 123 models
- SCOP (55 °C) 3.9: no. 9 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Remeha Confida MB 400-4
Data score 83/100
- SCOP (55 °C) 3.99: no. 4 of 122 models
- SCOP (35 °C) 5.34: no. 5 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
SolaX ALT04-SF0
Data score 82/100
- SCOP (35 °C) 5.25: no. 6 of 123 models
- SCOP (55 °C) 3.95: no. 6 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Image: TCLrequest removal TCL THM4DFB
Data score 81/100
- SCOP (35 °C) 5.8: the best of 123 models in this selection
- SCOP (55 °C) 4.38: the best of 122 models in this selection
Choose this model if you have underfloor heating and want to use as little electricity as possible.
SolaX ALT05-SF0
Data score 80/100
- SCOP (55 °C) 3.88: no. 10 of 122 models
- SCOP (35 °C) 5.12: no. 13 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Image: Viessmannrequest removal Viessmann Vitocal 200-A AWMOF-201.A1.06-230-V005
Data score 79/100
- SCOP (35 °C) 5.12: no. 13 of 123 models
- SCOP (55 °C) 3.85: no. 11 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
FoxESS HP1-5P-E
Data score 78/100
- SCOP (55 °C) 3.95: no. 6 of 122 models
- SCOP (35 °C) 5.12: no. 13 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Waterkotte EcoTouch Air Bloc 7006 (230V)
Data score 78/100
- SCOP (55 °C) 3.85: no. 11 of 122 models
- Outdoor unit sound power 46 dB(A): no. 25 of 123 models
Choose this model if you are keeping (some) radiators and the heat pump has to run at a higher flow temperature.
SolarEast BLN-004TC1
Data score 77/100
- SCOP (55 °C) 3.93: no. 8 of 122 models
- SCOP (35 °C) 5.21: no. 9 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
New Energy NE-F60HCR5INVMV2-PA
Data score 77/100
- SCOP (35 °C) 5.08: no. 20 of 123 models
- SCOP (55 °C) 3.66: no. 27 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
MULTIBETON Warmondo WM-S
Data score 76/100
- SCOP (35 °C) 5.08: no. 20 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
FoxESS HP1-5-E
Data score 75/100
- SCOP (55 °C) 3.98: no. 5 of 122 models
Choose this model if you are keeping (some) radiators and the heat pump has to run at a higher flow temperature.
Axen KS-40W/EN7BP
Data score 73/100
- SCOP (35 °C) 5.21: no. 9 of 123 models
- SCOP (55 °C) 3.85: no. 11 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Power World PW020-DKZLRS-E/S
Data score 71/100
- SCOP (55 °C) 3.69: no. 25 of 122 models
- SCOP (35 °C) 5.03: no. 28 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
iDM iPump A 2-7
Data score 69/100
- SCOP (35 °C) 5.12: no. 13 of 123 models
- SCOP (55 °C) 3.73: no. 22 of 122 models
- Weaker point: Refrigerant GWP 2,088 (R410A): no. 96 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Image: Boschrequest removal Bosch Compress 3800i AW CS3800iAW 4 OE-S
Data score 68/100
Image: Buderusrequest removal 
Image: Buderusrequest removal Buderus WLW176i.2-4 MBB AR E
Data score 68/100
Carrier Main Unit 30AWH006S1B-NG
Data score 68/100
- SCOP (35 °C) 5.03: no. 28 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Image: Viessmannrequest removal 
Image: Buderusrequest removal Buderus Logatherm WPL 6 ARB
Data score 67/100
- SCOP (35 °C) 5.13: no. 11 of 123 models
- Weaker point: Refrigerant GWP 2,088 (R410A): no. 96 of 122 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
Image: ELCOrequest removal ELCO AEROTOP SPK7
Data score 66/100
- SCOP (55 °C) 3.78: no. 20 of 122 models
Choose this model if you are keeping (some) radiators and the heat pump has to run at a higher flow temperature.
Panasonic Aquarea [WH-ADC0509L3E5AN / WH-WDG05LE5]
Data score 66/100
- SCOP (35 °C) 5.06: no. 26 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
![Panasonic Aquarea [WH-SDC0509L3E5 / WH-WDG05LE5]](/img/p/heatpumps/panasonic-deutschland-aquarea-wh-sdc0509l3e5-wh-wdg05le5-480.webp?v=20261002)
Image: Panasonicrequest removal Panasonic Aquarea [WH-SDC0509L3E5 / WH-WDG05LE5]
Data score 66/100
- SCOP (35 °C) 5.06: no. 26 of 123 models
Choose this model if you have underfloor heating and want to use as little electricity as possible.
All figures at a glance
| # | Model1,2,3 | Data score | Rated output 35 °C | SCOP (35 °C) | SCOP (55 °C) | Outdoor unit sound power | Refrigerant |
|---|---|---|---|---|---|---|---|
| 1 | ACOND Grandis N | 88 | 4 kW | 5.38 | 4.05 | 46 dB(A) | R290 |
| 2 | Clivet WiSAN-PMP 1 S 2.1 | 85 | 5 kW | 5.23 | 3.9 | 46 dB(A) | R290 |
| 3 | Remeha Confida MB 400-4 | 83 | 5.3 kW | 5.34 | 3.99 | 48 dB(A) | R290 |
| 4 | SolaX ALT04-SF0 | 82 | 4.21 kW | 5.25 | 3.95 | 48 dB(A) | R290 |
| 5 | TCL THM4DFB | 81 | 5 kW | 5.8 | 4.38 | 51 dB(A) | R290 |
| 6 | SolaX ALT05-SF0 | 80 | 5 kW | 5.12 | 3.88 | 48 dB(A) | R290 |
| 7 | Viessmann Vitocal 200-A AWMOF-201.A1.06-230-V005 | 79 | 5 kW | 5.12 | 3.85 | 48 dB(A) | R290 |
| 8 | FoxESS HP1-5P-E | 78 | 5 kW | 5.12 | 3.95 | 49 dB(A) | R290 |
| 9 | Waterkotte EcoTouch Air Bloc 7006 (230V) | 78 | 5.3 kW | 5 | 3.85 | 46 dB(A) | R290 |
| 10 | SolarEast BLN-004TC1 | 77 | 4.01 kW | 5.21 | 3.93 | 51 dB(A) | R290 |
| 11 | New Energy NE-F60HCR5INVMV2-PA | 77 | 4.84 kW | 5.08 | 3.66 | 47 dB(A) | R290 |
| 12 | MULTIBETON Warmondo WM-S | 76 | 5 kW | 5.08 | 3.65 | 47 dB(A) | R290 |
| 13 | FoxESS HP1-5-E | 75 | 5 kW | 5 | 3.98 | 49 dB(A) | R290 |
| 14 | Axen KS-40W/EN7BP | 73 | 4.2 kW | 5.21 | 3.85 | 53 dB(A) | R290 |
| 15 | Power World PW020-DKZLRS-E/S | 71 | 4.18 kW | 5.03 | 3.69 | 49 dB(A) | R290 |
| 16 | iDM iPump A 2-7 | 69 | 5 kW | 5.12 | 3.73 | 46 dB(A) | R410A |
| 17 | Bosch Compress 3800i AW CS3800iAW 4 OE-S | 68 | 4 kW | 4.99 | 3.6 | 48 dB(A) | R290 |
| 18 | Buderus Logaplus M WLW166i-4 MBB AR E (WLW-4 MBB AR & Logatherm WLW176i.2 E) | 68 | 4 kW | 4.99 | 3.6 | 48 dB(A) | R290 |
| 19 | Buderus WLW176i.2-4 MBB AR E | 68 | 4 kW | 4.99 | 3.6 | 48 dB(A) | R290 |
| 20 | Carrier Main Unit 30AWH006S1B-NG | 68 | 5 kW | 5.03 | 3.65 | 51 dB(A) | R290 |
| 21 | Viessmann Vitocal 250-A IDU-A Hybrid HWMIW.A1.19-V054 / ODU 250-A AWMOF-251.A1.06-230-V002 (Keymark 45936) | 67 | 5.41 kW | 4.71 | 3.65 | 47 dB(A) | R290 |
| 22 | Buderus Logatherm WPL 6 ARB | 67 | 5.43 kW | 5.13 | 3.65 | 47 dB(A) | R410A |
| 23 | ELCO AEROTOP SPK7 | 66 | 5.59 kW | 4.92 | 3.78 | 52 dB(A) | R290 |
| 24 | Panasonic Aquarea [WH-ADC0509L3E5AN / WH-WDG05LE5] | 66 | 5 kW | 5.06 | 3.62 | 52 dB(A) | R290 |
| 25 | Panasonic Aquarea [WH-SDC0509L3E5 / WH-WDG05LE5] | 66 | 5 kW | 5.06 | 3.62 | 52 dB(A) | R290 |
How this ranking is made
This selection is put together automatically from the 123 models in our database that meet the criteria above. We only include models whose figures for the ranking are known: without those values a model cannot be compared fairly, so it drops out. The list is recalculated with every data update, so the order can change as soon as manufacturers or registers publish new values.
The order follows a data score from 0 to 100. For each feature we determine a model’s position relative to the other models in this selection: the best value counts as 100, the weakest as 0, and equal values share the same position. We add up those positions with weights: SCOP (35 °C) 30 % · SCOP (55 °C) 25 % · Outdoor unit sound power 25 % · Refrigerant GWP 20 %. A feature that is unknown for a model does not count; if more than 40 per cent of the weight is missing, the model is left out. If two scores are equal, SCOP (35 °C) decides.
The reasoning for each place is derived automatically from the same data. We name the features on which the model is in the best quarter of this selection, functions that not every model has, and a weaker point if the model falls in the bottom quarter on it. The line ‘Choose this model if …’ links the most heavily weighted strength to a situation where it matters. This is not a test and not personal advice: the installation, your home and the price also decide what works best for you.
The values come from EPREL, Keymark and manufacturers; the product page shows the source of every value. How we collect and check the data →
More selections
- Quietest 4–6 kW air-to-water heat pumps
- Most efficient 4–6 kW air-to-water heat pumps
- Quietest 6–8 kW air-to-water heat pumps
- Most efficient 6–8 kW air-to-water heat pumps
- Quietest 8–10 kW air-to-water heat pumps
- Most efficient 8–10 kW air-to-water heat pumps
- Quietest 10–14 kW air-to-water heat pumps
- Most efficient 10–14 kW air-to-water heat pumps
- Best air source heat pumps
- Best 6–8 kW air source heat pumps
- Best 8–12 kW air source heat pumps
- Best 12–16 kW air source heat pumps
- Quietest air source 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)
- Water-to-water heat pumps (groundwater)
- Best hybrid heat pumps (with a gas boiler)
Sources
- European Product Registry for Energy Labelling (EPREL) – heat pumps — Europese Commissie · accessed 18 Oct 2026
- Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026
- List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026