Vaillant
arotherm plus 8kW
German-engineered ASHP with A+++ energy rating and among the lowest noise outputs in class at 46dB(A). Eligible for the Boiler Upgrade Scheme grant.
~£14,500 installed (after £7,500 BUS grant: ~£7,000)
How it scores
Scores based on published manufacturer specifications and weighted criteria — not lab testing. Methodology.
Specifications
- Scop
- 4.2
- Type
- air-source
- Noise db
- 46
- Output kW
- 8
- Refrigerant
- R290
- Warranty years
- 7
- Bus grant eligible
- Yes
What I noticed
The Vaillant arotherm plus is consistently rated among the top performers by MCS installers in the UK. Its R290 (propane) refrigerant has a GWP of 3 — a fraction of the R410A used in older units — and the efficiency figures hold up well in real UK conditions rather than just lab tests.
Who it suits
Homes with radiators sized for 55°C flow temperature or underfloor heating. Works well as a straight boiler replacement if your home has been reasonably insulated. The arotherm plus pairs cleanly with Vaillant's own hot water cylinder and controls, keeping the install tidy.
Watch for
R290 refrigerant requires F-Gas certified engineers. Not all installers are licensed — check before booking. The unit is slightly larger than some competitors at ground level, which matters on smaller plots.