Moving from dirty oil to air source central heating

by Mars

With the solar panel array fully up and running, we have installed Global Energy Systems’ Caernarfon 18kW Eco Air Source Heat Pump making the move from oil to air source central heating.

The reason we opted for the Caernarfon CAER410AMOD1 (that’s the model number) was because unlike Mitsubishi, Hitachi and other makers of heat pumps, Global Energy design and manufacture a pump for the UK climate, and we required a pump powerful enough to heat our entire house.

We all know it rains a lot in the UK and there is a lot of moisture in the air,  so when the heat pump strips 8 degrees C out of the atmosphere, the condensate causes an ice build up which requires the heat pump to defrost in a quick and controlled manner, and the Caernarfon has, according to Global Energy Systems, been designed to do just that. We will monitor this claim.

By watching this video you’ll get an overview of the heat pump we’ve installed, along with the other heating components that we have in operation around the house from controls for the underfloor heating and radiators through to the equipment we have in the utility room where the new water tank has been installed.

Other things to know about the heat pump
  • The Caernarfon 18kW Eco Air Source Heat Pump has a  larger evaporator to enable the pump to draw a greater volume of air over a larger area of evaporator thus transferring a larger amount of heat to the refrigerant in the evaporator.
  • The evaporator is placed at a higher level to prevent cold air recirculation, purportedly resulting in a better performance levels.
  • Designed for the British climate down to -20 degrees centigrade. This is a bold claim and we will definitely watch this.

We are working on a new video to evaluate the performance of our air source central heating system.

Post updated (29 January 2020) – please see the reviews and videos by visiting the links below:


We will always be transparent about any sponsorships, promotions, affiliate links or ads. We purchase all products with our own money, unless otherwise stated. We will only recommend products in good faith, that we have actually used and like.If you purchase the items by clicking the Amazon link above, we will receive a small commission. All of our reviews and opinions are based on our own personal experience with products or brands, and this may not be the same for everyone. Video topics and product choices are all of our own choosing.

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Stephen Durrant
Stephen Durrant
2 years ago

Hi. We have been following your good updates on experience with air heat source pumps and have had a bad experience this winter with our system.
It was constantly freezing up and in defrost mode and the house was colder than normal. Our last monthly bill was £380 and twice the amount for the same time of year. I was wondering if one could add a wood burner with a back boiler and assist the heat pump. We switched from gas, but are now worried about the cost of heating our old house, with no cavity walls. It would be good if the government would help with electricity prices ????

Reply to  Stephen Durrant
2 years ago

Thanks for the feedback Stephen. For context, can you please tell us what pump you have and the space you’re trying to heat. From a technical perspective I don’t know if you can do that with a wood burner, but we are launching a new exciting project in a few weeks’ time where hopefully these kinds of questions will be answered.

Interesting to hear you’ve had a gas boiler retrofit. Did you change any of your rads, and do you have UFH?

Stephen Durrant
Stephen Durrant
2 years ago

We have an LG V 18Kw pump with a completely new radiator system, as the old one had micro bore and was rusted up.
What is UFH ?

Stephen Durrant
Stephen Durrant
2 years ago

We have an old three bedroom house with solid brick walls and no cavity insulation, but have plenty of insulation in the attic

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