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Viessmann Vitocal 250-A AWO-E-AC 251.A19

Viessmann Vitocal 250-A AWO-E-AC 251.A19
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The Viessmann Vitocal 250-A AWO-E-AC 251.A19 is an air-to-water heat pump with a SCOP of 4.86 (35 °C) and a sound power level of 48 dB(A).1,2

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SCOP (35 °C)
4.861

Seasonal efficiency: how much heat you get per kWh of electricity across a heating season.

Heating capacity (A7/W35)
9kW2
Official source
Outdoor unit sound power
48dB(A)1
Official source
Refrigerant
R2901
Official source
Type (source)
Air-to-water1
Official source

Technical specifications

General
Type (source)Air-to-water1
Compressors11
Capacity controldrehzahlregelung1
Performance
Heating capacity (A7/W35)9 kW2
Rated output 35 °C13.61 kW1
Rated output 55 °C13.18 kW1
Min. outdoor temperature-20 °C2
Efficiency
SCOP (35 °C)4.861
SCOP (55 °C)3.881
Seasonal efficiency ηs 35 °C191 %1
Seasonal efficiency ηs 55 °C152 %1
Energy label 35 °CA+++2
Energy label 55 °CA+++2
COP A7/W355.271
COP A2/W354.061
COP A-7/W352.871
Noise
Outdoor unit sound power48 dB(A)1
Indoor unit sound power40 dB(A)1
Refrigerant
RefrigerantR2901
Refrigerant GWP32
Refrigerant charge2 kg1
Electrical
Max. power input7.2 kW1
Connectivity & smart
SG ReadyYes1

How it ranks

SCOP (35 °C): better than 61% of comparable models in our database (Heat pumps · Air-to-water · 10–14 kW; n = 308).

Rank 117 of 309

Compared with every model on VersusIndex in the same group with a known value; equal values do not count as better. This says nothing about price, installation or reliability.

Variants

This model is registered in 23 combinations (for example with a different indoor unit or cylinder) with exactly the same performance. All figures on this page apply to each of these types. The part of the type number that differs is in bold; small differences (e.g. cylinder volume or anode) are listed after it:

  • Vitocal 250-A AWO-E-AC 251.A19
  • Vitocal 250-A AWO-E-AC 251.A19 2C
  • Vitocal 250-A AWO-E-AC-AF 251.A19
  • Vitocal 250-A AWO-E-AC-AF 251.A19 2C
  • Vitocal 250-AH HAWO-AC 252.A19
  • Vitocal 250-AH HAWO-AC-AF 252.A19
  • Vitocal 252-A AWOT-E-AC 251.A19
  • Vitocal 252-A AWOT-E-AC 251.A19 2C
  • Vitocal 252-A AWOT-E-AC-AF 251.A19
  • Vitocal 252-A AWOT-E-AC-AF 251.A19 2C
  • Vitocal 250-A AWO-E-AC 251.A19
  • IDU-A Compact 2C AWMIT.A1.19-V056 ODU 250-A AWMOF-251.A1.19-400-V002
  • IDU-A Compact AWMIT.A1.19-V053 ODU 250-A AWMOF-251.A1.19-400-V002
  • IDU-A Modular AWMIW.A1.19-V051 ODU 250-A AWMOF-251.A1.19-400-V002
  • Vitocal 250-A AWO-E-AC 251.A19 2C
  • Vitocal 250-A AWO-E-AC-AF 251.A19 2C
  • Vitocal 250-A AWO-E-AC-AF 251.A19
  • Vitocal 250-AH HAWO-AC 252.A19
  • Vitocal 250-AH HAWO-AC-AF 252.A19
  • Vitocal 252-A AWOT-E-AC 251.A19 2C
  • Vitocal 252-A AWOT-E-AC 251.A19
  • Vitocal 252-A AWOT-E-AC-AF 251.A19 2C
  • Vitocal 252-A AWOT-E-AC-AF 251.A19

Manufacturer documentation

External links to Viessmann's official website. The manufacturer may change or move documents; where they differ, the manufacturer's latest version applies.

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Frequently asked questions

Which refrigerant does the Viessmann Vitocal 250-A AWO-E-AC 251.A19 use?

The Viessmann Vitocal 250-A AWO-E-AC 251.A19 uses R290.1,2

Sources

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