Mitsubishi Electric Ecodan R32 Monobloc (PUZ-WM85YAA-BS)

Specifications and technical data

Also known as: PUZ-WM85YAA

✓ BUS eligibleAir Source (ASHP)ResidentialR328.5 kW

Manufacturer	Mitsubishi Electric
Model	Ecodan R32 Monobloc
Model code	PUZ-WM85YAA-BS
Heat pump type	Air Source (ASHP) All Air Source heat pumps →
Application	Residential All Residential heat pumps →
Refrigerant	R32 All R32 heat pumps →
Mode	Heating & cooling
Heating capacity	8.5 kW
Max heating output (low temp)	8.5 kW at A-7/W35
COP (heating)	2.6 at A-7/W35
SCOP (heating)	4.81 at W35
Operating range (air)	-20 to 35 °C
Electrical supply	380-415V (Three Phase)
Dimensions (H×W×D)	1020 × 1050 × 480 mm
Operational Weight	111 kg
Sound power level	58 dB(A) (Sound Power LW(A))
Data added	2026-10-20
Data source	Mitsubishi Electric Ecodan PUZ-WM85YAA product information sheet (Jan 2025)
Verification	Verified by a human
Boiler Upgrade Scheme	✓ BUS eligible — Listed on the Ofgem BUS Product Eligibility List (24 Sep 2026). Grant also needs an MCS-certified installer and a qualifying system design. Funding guide
PEL certificate no.	037-0033-20-06
MCS certification	✓ MCS listed
MCS certificate no.	037-0033-20-06

Free data sheet (PDF) →

Check noise at a neighbour’s window (MCS 020 a) →

Mitsubishi Electric Ecodan PUZ-WM85YAA-BS 8.5 kW R32 monobloc air-to-water heat pump, full capacity maintained at low ambient, three-phase 400 V.

Where to buy (UK)

UK Supplier	The Heat Pump Warehouse
UK Supplier	Secon Renewables
UK Supplier	City Plumbing
UK Supplier	BHL
UK Supplier	Quality Heating

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Data is compiled from manufacturer sources and may contain errors or gaps. Always confirm specifications with the manufacturer before making decisions.

Reviews & further reading

Manufacturer Ecodan R32 Air Source Heat Pump — Mitsubishi Electric
Manufacturer Ecodan R32 Compact Air Source Heat Pump — Mitsubishi Electric
Review Mitsubishi Ecodan air source heat pump review — Federation of Master Builders
Covers the Ecodan range generally, not this specific R32 monobloc variant only.
Review Mitsubishi Ecodan 11.2kw R410a monobloc heat pump review — Homebuilding & Renovating
Long-term homeowner review (5 years on) of an earlier R410A Ecodan monobloc from the same range; written by Homebuilding's renewables expert David Hilton.