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Heat pumps · UK

BoschCSH3800iAW 13-T

Bosch CSH3800iAW 13-T
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The Bosch CSH3800iAW 13-T is an air-to-water heat pump with a SCOP of 4.98 (35 °C) and a sound power level of 51 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 2.0 m; against a wall 2.8 m.1

Last updated: Technical specifications Rules in the UK ⇄ Compare this model
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SCOP (35 °C)
4.981

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

Heating capacity (A7/W35)
11.05kW1
Official source
Outdoor unit sound power
51dB(A)1
Official source
Refrigerant
R2901
Official source
Type (source)
Air-to-water1
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 2 m
Against wall 2.8 m
In corner 4 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 12.5 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 3.85. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Heat pump grants in the UK explained →

Technical specifications

General
Type (source) Air-to-water1
Performance
Heating capacity (A7/W35) 11.05 kW1
Rated output 35 °C 12.5 kW1
Rated output 55 °C 12.5 kW1
Min. outdoor temperature -22 °C1
Efficiency
SCOP (35 °C) 4.981
SCOP (55 °C) 3.851
Seasonal efficiency ηs 35 °C 196 %1
Seasonal efficiency ηs 55 °C 151 %1
Energy label 35 °C A, , , 1
Energy label 55 °C A, , , 1
COP A7/W35 4.461
Noise
Outdoor unit sound power 51 dB(A)1
Indoor unit sound power 34 dB(A)1
Refrigerant
Refrigerant R2901
Refrigerant GWP 31
Refrigerant charge 1.37 kg1

Manufacturer documentation

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

Frequently asked questions

Can I install the Bosch CSH3800iAW 13-T 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 51 dB(A) that indicatively means 2.0 m free-standing, 2.8 m against a wall or 4.0 m in a corner. Your MCS installer must confirm this.1

How much Boiler Upgrade Scheme grant can you get for the Bosch CSH3800iAW 13-T?

£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 Bosch CSH3800iAW 13-T use?

The Bosch CSH3800iAW 13-T uses R290.1

Sources

  1. Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 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