Baxi
The Baxi Assure HP55-13-3-PHMB is a 14 kilowatt air source heat pump with an A plus-plus-plus efficiency rating and a 52 decibel sound power level.
The Baxi Assure HP55-13-3-PHMB is a 14 kW air source heat pump designed for domestic heating and hot water applications. Introduced in 2019, this model provides a high-capacity solution for larger UK properties requiring efficient low-carbon heating. With an ErP rating of A+++ at a 35°C flow temperature and A++ at 55°C, it meets stringent efficiency standards. This technical guide provides engineers and homeowners with essential specifications, sound data, and performance metrics for the Assure HP range.
Stick a QR tag on the case, scan it on every service and give your customer a permanent, shareable service history they can pull up from any phone.
Permanent, shareable service history
One QR scan on the boiler surfaces every previous fault, part change and visit — no paperwork to dig out.
Free AI fault diagnostics, built in
Every tag you fit unlocks the AI diagnostic tool for that exact model — paste a fault code, get a ranked cause list.
Your name on the boiler forever
When the next service or breakdown comes around the homeowner scans and sees your number first.
First 12 BoilerTags are free
Tag every install and service you do from now on — the subscription only kicks in once you scale past your first dozen.
Diagnosing a fault on a Baxi Assure HP55-13-3-PHMB right now?
Try the free AI fault diagnostics tool — no signup needed.
Full technical specifications extracted from the manufacturer brochure. Empty sections are hidden.
The Baxi Assure HP55-13-3-PHMB represents a high-output air source heat pump within the Baxi Assure product family. According to the manufacturer's ErP documentation, this unit delivers a nominal capacity of 14 kW, making it suitable for larger detached homes or properties with higher heat loss requirements. The system is engineered to provide a maximum flow temperature of 55°C, which allows for compatibility with appropriately sized radiators or underfloor heating systems, though performance is optimised at lower flow temperatures.
Efficiency is a core metric for this appliance. The unit achieves an ErP rating of A+++ when operating at a 35°C flow temperature, which is the standard for modern underfloor heating installations. For traditional radiator circuits requiring a 55°C flow, the unit maintains an A++ rating. These ratings indicate a high seasonal coefficient of performance, though specific SCOP values should be verified against the installation's design temperature.
A critical consideration for UK planning permission and MCS-020 compliance is the sound power level. The Assure HP55-13-3-PHMB is rated at 52 dB(LwA). This relatively low sound power level assists in meeting the noise at the property boundary requirements for Permitted Development, although a full noise assessment may still be necessary depending on the distance to neighbouring habitable rooms.
Introduced around 2019, the Assure HP55-13-3-PHMB was part of Baxi’s expansion into the renewable sector, specifically targeting the new-build and social housing markets where the Assure brand is established. As the data for this specific model is primarily extracted from ErP labelling, installers should cross-reference the physical unit’s data plate for specific electrical requirements, such as the required MCB rating and startup current, which are not always detailed in high-level marketing literature.
Hydraulic integration requires careful planning. Given the 14 kW output, ensuring adequate water flow rates and system volume is essential to prevent short-cycling and ensure efficient defrost cycles. While the documentation does not specify the internal pump curve, standard practice for units of this capacity involves checking if a buffer tank or volumiser is required to maintain the minimum system volume. The unit’s performance in the UK climate is supported by its air-source design, though capacity will naturally fluctuate based on outdoor ambient temperatures.
Common questions from engineers and homeowners about the Baxi Assure HP55-13-3-PHMB.
We hold the Baxi Assure HP55-13-3-PHMB manual — and every other UK boiler and heat pump brochure. Sign up and pull any model up from your phone, on the job.
Sign up to access brochuresTag it before you leave. Next scan shows every service, fault and part change — and the AI diagnostic tool is free on every tag you fit.
Specifications on this page are extracted from the manufacturer brochure. Always cross-check against the latest datasheet before commissioning or quoting. Last updated 30 April 2026.