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Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) vs Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001

SCOP (35 °C): Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) 4.56, Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001 4.44. The Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) is better on 7 of 13 comparable points.

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Who wins where

  • Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M)
  • Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001
PerformanceEfficiencyNoiseRefrigerantConnectivity & smart

Biggest differences

FactCompress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M)Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001
COP A7/W354.816.2
COP A-7/W352.353
Refrigerant charge0.95 kg1.2 kg
Outdoor unit sound power42 dB(A)48 dB(A)
Indoor unit sound power37 dB(A)40 dB(A)
Rated output 55 °C6.6 kW6.17 kW
All specifications ↓

Score per area = position (0–100) relative to all 1350 models in this category; higher is better.

BoschCompress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M)ViessmannVitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001
Grants & market
Boiler Upgrade Scheme£7,500 – £9,000£7,500 – £9,000
General
Type (source)Air-to-water1Air-to-water1
Performance
Heating capacity (A7/W35)–5.6 kW2
Rated output 35 °C6.6 kW✓16.47 kW1
Rated output 55 °C6.6 kW✓16.17 kW1
Min. outdoor temperature–-20 °C2
Efficiency
SCOP (35 °C)4.56✓14.441
SCOP (55 °C)3.4813.58✓1
Seasonal efficiency ηs 35 °C179 %✓1176 %1
Seasonal efficiency ηs 55 °C136 %1140 %✓1
Energy label 35 °C–A+++2
Energy label 55 °C–A++2
COP A7/W354.8116.2✓1
COP A2/W354.0314.2✓1
COP A-7/W352.3513✓1
SEER (cooling)2.561–
Noise
Outdoor unit sound power42 dB(A)✓148 dB(A)1
Indoor unit sound power37 dB(A)✓140 dB(A)1
Refrigerant
RefrigerantR2901R2901
Refrigerant GWP–32
Refrigerant charge0.95 kg✓11.2 kg1
Electrical
Max. power input3.15 kW11.14 kW1
Connectivity & smart
SG ReadyYes1Yes1

Frequently asked questions

Which is better: the Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) or the Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001?

SCOP (35 °C): Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) 4.56, Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001 4.44. The Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) is better on 7 of 13 comparable points.

What is the SCOP (35 °C) of the Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) and the Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001?

Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M): 4.56. Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001: 4.44.

Which is better on COP A7/W35: the Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) or the Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001?

Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001: 6.2. Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M): 4.81.

Which is better on COP A-7/W35: the Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M) or the Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001?

Viessmann Vitocal 250-A IDU-A AWMIW.A1.19-V052 / ODU 250-A AWMOF-251.A1.08-230-V001: 3. Bosch Compress CS6800iAW 7 ORM-S (AW 7 OR-S + CS6800iAW 12 M): 2.35.

How we collect and check this data →

Sources

  1. List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
  2. Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026