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Heat pumps · UK

Viessmann Climate SolutionsIDU-A Compact AWMIT.A1.19-V053 / ODU 250-A AWMOF-251.A1.13-230-V002

The Viessmann Climate Solutions IDU-A Compact AWMIT.A1.19-V053 / ODU 250-A AWMOF-251.A1.13-230-V002 is an air-to-water heat pump with a SCOP of 4.96 (35 °C) and a sound power level of 50 dB(A). Under permitted development the limit is 37 dB(A) measured 1 m in front of the centre of a neighbour’s habitable-room door or window. Free-standing, the indicative minimum distance is 1.8 m; against a wall 2.5 m.1

Last updated: Technical specifications Rules in the UK
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SCOP (35 °C)
4.961

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

Outdoor unit sound power
50dB(A)1
Official source
Refrigerant
R2901
Official source
Rated output 35 °C
12.42kW1
Official source
Rated output 55 °C
12.1kW1
Official source
UK

Rules in the UK

Minimum distance to your neighbour

MCS 020(a) (England, permitted development since 29 May 2025)2 · 1 m in front of the centre of a neighbour’s habitable-room door or window

Permitted development (MCS 020(a)) ≤ 37 dB(A) · LAeq,5min
Free-standing 1.8 m
Against wall 2.5 m
In corner 3.6 m

Indicative calculation (hemispherical, no barriers). Not a substitute for an MCS 020 assessment.

Boiler Upgrade Scheme

Check conditions

£7,500 – £9,0003Fixed grant (England & Wales)

Fixed grant in England and Wales, deducted from your installer’s quote. £9,000 when replacing oil or LPG off the gas grid (until March 2027). Scotland: Home Energy Scotland grant instead.4,5

  • Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
  • Rated output 12.42 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 3.93. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Heat pump grants in the UK explained →

Technical specifications

General
Type Air-to-water1
Compressors 11
Capacity control Inverter1
Performance
Rated output 35 °C 12.42 kW1
Rated output 55 °C 12.1 kW1
Efficiency
SCOP (35 °C) 4.961
SCOP (55 °C) 3.931
Seasonal efficiency ηs 35 °C 195 %1
Seasonal efficiency ηs 55 °C 154 %1
COP A7/W35 6.51
COP A2/W35 51
COP A-7/W35 3.11
Noise
Outdoor unit sound power 50 dB(A)1
Indoor unit sound power 40 dB(A)1
Refrigerant
Refrigerant R2901
Refrigerant charge 2 kg1
Electrical
Max. power input 1.56 kW1
Connectivity & smart
SG Ready Yes1

Frequently asked questions

Can I install the Viessmann Climate Solutions IDU-A Compact AWMIT.A1.19-V053 / ODU 250-A AWMOF-251.A1.13-230-V002 without planning permission?

Under MCS 020(a) (England, permitted development since 29 May 2025) the unit must not exceed 37 dB(A) 1 m in front of the centre of a neighbour’s habitable-room door or window. With a sound power of 50 dB(A) that indicatively means 1.8 m free-standing, 2.5 m against a wall or 3.6 m in a corner. Your MCS installer must confirm this.1

How much Boiler Upgrade Scheme grant can you get for the Viessmann Climate Solutions IDU-A Compact AWMIT.A1.19-V053 / ODU 250-A AWMOF-251.A1.13-230-V002?

£7,500 in England and Wales, provided the product and installer are MCS-certified (£9,000 when replacing oil or LPG off the gas grid, until March 2027). The installer applies and deducts the grant from your quote.1

Which refrigerant does the Viessmann Climate Solutions IDU-A Compact AWMIT.A1.19-V053 / ODU 250-A AWMOF-251.A1.13-230-V002 use?

The Viessmann Climate Solutions IDU-A Compact AWMIT.A1.19-V053 / ODU 250-A AWMOF-251.A1.13-230-V002 uses R290.1

Sources

  1. List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
  2. MCS 020(a) (England, permitted development since 29 May 2025)
  3. Boiler Upgrade Scheme: what you can get — GOV.UK · accessed 27 Sept 2026
  4. Boiler Upgrade Scheme: guidance for installers (V5) — Ofgem · accessed 27 Sept 2026
  5. Boiler Upgrade Scheme product eligibility — Ofgem · accessed 27 Sept 2026