Acond PRO-R Heat Pump

This review discusses the installation of an Acond heat pump in a neighbour’s house, which is a two-story, semi-detached stone cottage covering around 100 square meters. The cottage, which recently underwent renovations, now features 50mm PIR foam insulation plasterboards on the walls and underfloor heating in the lounge. The owner chose Thermal Earth for the installation primarily because they had an available slot, which was crucial as she was in the midst of significant renovations and lacked heating and hot water.

Thermal Earth conducted an initial heat loss report, estimating the house’s total heat loss at 5.8 kW with an exterior design temperature of -3C. Based on this, they recommended a heat pump from Acond, a Czech brand new to the UK market and, to my knowledge, exclusively used by Thermal Earth. The selected model was the Acond N, with an approximate output of 6kW. The Acond heat pump utilises the refrigerant R290, in contrast to the R32 used in most contemporary heat pumps.

Subsequent to agreeing on the installation, the homeowner informed Thermal Earth of potential future plans to convert a 30 square meter outhouse into living space. Thermal Earth then advised that this additional load, estimated between 600-1200 Watts, would exceed the capacity of the Acond N model. They recommended upgrading to the Acond PRO-R model, with a marked output of 16kW.

I became involved after the PRO-R unit was installed and operational, heating the home and its domestic hot water continuously. The homeowner expressed concerns over the resulting high energy bills, which ranged from £10-15 daily. A lack of handover instructions and the impression from installers that the heat pump could not be deactivated exacerbated her worries. Her attempts to communicate with the company were largely ignored, leading to significant frustration and highlighting a lack of customer focus on the company’s part.

Upon inspecting the installation, I identified insulation deficiencies both inside the house, where it was missing, and outside, where it was substandard in certain areas. Additionally, I was troubled by the significant increase in heat pump capacity, jumping from a nominal 6kW to 16kW. This led to the placement of the larger model at the far end of the garden, necessitating a lengthy pipe run back to the house.

I addressed these concerns in an email to the company, mentioning my intention to write this review. In response, one of the owners clarified that at the design temperature of -3C, the output of the PRO-N model was “less than 5kW,” while the PRO-R model was 9 kW. He also provided output graphs for both units, which, after verifying the design flow temperature was 45C, allowed me to correct the outputs to 6.5 kW for the PRO-N and 14 kW for the PRO-R at that specific flow temperature.

Subsequently, the company arranged for an engineer’s visit and sent over a user manual by email. Although the manual was somewhat helpful, it was not comprehensive and referred to a different wall-mounted control unit.

During the visit, the engineer acknowledged the insulation issues and attempted to grant the homeowner access to the heat pump’s control software. Due to poor internet connectivity, he was unable to complete this setup but managed to schedule the heat pump over a local network connection as per the homeowner’s preferences. It’s worth noting that while most of the heat pump’s controls can be accessed via a wall-mounted control box, this method is cumbersome and lacks scheduling capabilities. The engineer committed to returning the following week to attempt setting up internet access again and to address any remaining minor issues.

The follow-up visit concluded with all minor issues being resolved satisfactorily, although internet access to the heat pump’s controller was not established. I also sought to secure a guarantee from the company to replace the oversized heat pump with a smaller model if it cycled too frequently in mild weather, a request the company declined.

Due to the house’s poor internet connection, I proposed that if the company could send me instructions on accessing the heat pump via the local network, I could set up access to the controller software myself. The engineer agreed to this plan. However, another week passed without the arrival of the instructions, and during this time, the house’s heating system appeared to be malfunctioning.

At this juncture, the company’s approach shifted, and they expressed reluctance to provide the instructions, arguing that a stronger internet signal was necessary for using the control app. The client countered, noting that one of the installers had previously mentioned an internet connection was preferable but not mandatory. In response, Thermal Earth referred to a detailed agreement the client had signed months earlier.

Following considerable debate and the client’s decision to withhold the final payment, the company finally provided the instructions. Once connected to the heat pump’s control software via a local network, we discovered that the system was set to heat domestic hot water to over 62C daily, despite the client not having any operational hot water taps and requesting this function be disabled.

Attempts to modify the heating and hot water schedules were unsuccessful; the heat pump would activate at the set times, yet no temperature increase was detected at the radiators. After additional discussions with Thermal Earth, they consented to dispatch another engineer to address the problems.

The new engineer quickly identified and resolved the issues within an hour of his arrival. The control software had both heating pumps deactivated, blocking heat delivery to the radiators and underfloor heating. Furthermore, the immersion heater for the hot water tank had been left on, causing continuous heating of the water to the thermostat’s set temperature, likely since the initial handover more than a month prior.

Fortunately, the owner now has a fully operational heat pump system. Despite receiving written assurances from the company that the heat pump is appropriately sized and will not cycle excessively, they have firmly declined any offer to replace it with a smaller model if it fails to meet performance expectations. I plan to update this review in the future with further evaluation of the system’s performance.