SolaX ALT04-SF0 vs Viessmann IDU-A AWMIW.A1.19-V052 / ODU 150-A AWMOF-151.A1.04-230-V001
SCOP (35 °C): SolaX ALT04-SF0 5.25, Viessmann IDU-A AWMIW.A1.19-V052 / ODU 150-A AWMOF-151.A1.04-230-V001 4.48. The SolaX ALT04-SF0 is better on 11 of 14 comparable points.
Who wins where
- SolaX ALT04-SF0
- Viessmann IDU-A AWMIW.A1.19-V052 / ODU 150-A AWMOF-151.A1.04-230-V001
Biggest differences
| Fact | ALT04-SF0 | IDU-A AWMIW.A1.19-V052 / ODU 150-A AWMOF-151.A1.04-230-V001 |
|---|---|---|
| Refrigerant charge | 0.74 kg | 1.2 kg |
| Seasonal efficiency ηs 55 °C | 155 % | 127 % |
| SCOP (55 °C) | 3.95 | 3.25 |
| Seasonal efficiency ηs 35 °C | 207 % | 176 % |
| SCOP (35 °C) | 5.25 | 4.48 |
| Heating capacity (A7/W35) | 4.6 kW | 4 kW |
Score per area = position (0–100) relative to all 1350 models in this category; higher is better.
| Technical specifications | SolaXALT04-SF0 | ViessmannIDU-A AWMIW.A1.19-V052 / ODU 150-A AWMOF-151.A1.04-230-V001 |
|---|---|---|
| Grants & market | ||
| Boiler Upgrade Scheme | £7,500 – £9,000 | £7,500 – £9,000 |
| General | ||
| Type (source) | Air-to-water 1 | Air-to-water 1 |
| Performance | ||
| Heating capacity (A7/W35) | 4.6 kW ✓ 2 | 4 kW 3 |
| Rated output 35 °C | 4.21 kW ✓ 1 | 4.08 kW 1 |
| Rated output 55 °C | 4.29 kW ✓ 1 | 3.77 kW 1 |
| Min. outdoor temperature | -22 °C ✓ 2 | -20 °C 3 |
| Efficiency | ||
| SCOP (35 °C) | 5.25 ✓ 1 | 4.48 1 |
| SCOP (55 °C) | 3.95 ✓ 1 | 3.25 1 |
| Seasonal efficiency ηs 35 °C | 207 % ✓ 1 | 176 % 1 |
| Seasonal efficiency ηs 55 °C | 155 % ✓ 1 | 127 % 1 |
| Energy label 35 °C | A, , , 2 | A, , , 3 |
| Energy label 55 °C | A, , , 2 | A, , 3 |
| COP A7/W35 | 5.3 1 | 5.62 ✓ 1 |
| COP A2/W35 | – | 4.33 1 |
| COP A-7/W35 | 3.47 ✓ 1 | 3.12 1 |
| Noise | ||
| Outdoor unit sound power | 48 dB(A) ✓ 1 | 51 dB(A) 1 |
| Indoor unit sound power | – | 40 dB(A) 1 |
| Refrigerant | ||
| Refrigerant | R290 1 | R290 1 |
| Refrigerant GWP | 3 2 | 3 3 |
| Refrigerant charge | 0.74 kg ✓ 1 | 1.2 kg 1 |
| Electrical | ||
| Max. power input | 2 kW 1 | 0.8 kW 1 |
| Connectivity & smart | ||
| SG Ready | Yes 1 | Yes 1 |
Sources
- List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
- Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026
- Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026