28 September 2021

Caernarfon 18kW ASHP

We installed the Caernarfon 18kW air source heat pump (ASHP) from Global Energy Systems in March 2019 to replace an oil boiler in a bid to heat approximately 4,000sqft of living space.

We have a relatively well insulated Victorian farmhouse with double glazing and in-wall, cavity insulation, and our EPC rating was D (67). Over 2019/2020, we’ve spent considerable time addressing drafts and making the house as draft-proof as possible to keep heat in, and prevent heat from escaping.

We installed our ASHP about 20 metres away from the house and ran the piping to the new water tank via a heavily insulated heat-loss pipe. The reason we set the pump away from the house was because the machine itself is very large (1.80m tall) and it would have looked out of place.

Since our installation was a retrofit project, we didn’t change or modify the underfloor heating or radiators, as there were no issues raised during the survey.

You can watch this video to see the full installation process in a period property and what it entailed.

In terms of performance, the pump heats the house efficiently when outside temperatures are at 5-6C, but we notice that the house gets considerably colder during cold winter spells where temperatures drop to 0C or below.

To find out more about how the Caernarfon 18kW air source heat pump performed in the winter, we’d recommend you watch this video.

If you’d like to see how the pump performed when the last cold spell hit the UK in February 2021 (with temperatures dropping to -6C) you can watch the video below.

During this cold snap, we discovered that certain rooms were not being sufficiently heated, so we called the manufacturer and they came out to investigate. The outcome is pending and we’ll update this review accordingly.

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