Air Source Heat Pump
Specialists in Cornwall

By using air from outside we can provide you with the perfect indoor climate, even at the coldest times of the year.

What is an air source heat pump?

With minimal electricity, air source heat pumps transfer energy from the air into heat to provide you with all your central heating and hot water needs.

How it works

There are three main components that make up this technology. The evaporator (the first heat exchanger), compressor and condenser (the second heat exchanger) work together using the outside air to create heating and hot water.

The air source heat pump absorbs air through fins at the back of the unit. There is energy in the air that can be used by an air source heat pump at temperatures as low as -20°C. 

Once in the heat pump it causes the refrigerant to evaporate. 

The compressor increases the temperature of the refrigerant to a usable temperature. 

Heat is then transferred via a condenser which acts as a second heat exchanger. This in turn causes the refrigerant to turn back into a liquid within the condenser.

Lastly, the colder water from the central heating passes through the heat exchanger and withdraws this heat for use in radiators or underfloor heating and hot water. 

Air Source Heat Pumps Cornwall

Why are air source heat pumps worth it?

They are extremely efficient

They are
cost effective

Renewable sources of electricity

Qualify for the Government RHI

Constant heating reduces damp issues



Air source heat pump survey

Our free survey will help us specify which air source heat pump is best for you. We will carry out a detailed air source heat pump survey and heat loss report of your property.

The older

Many properties in Cornwall are stone or granite built with no cavity wall insulation and as a result have thermal bridging, all details we pick up at our initial survey. The more information we have before we start working on the heat loss report means we can provide you with the most accurate specification and make sure it comfortably covers your homes heating demands. We have installed many heat pumps in Grade II buildings.

Proximity to
the coastline

You’re right to be concerned as it is often an oversight for installers outside of Cornwall. However, we always consider your local environment at survey stage. For properties near to the coast we recommend coastal protection in the form of blygold coating. Salt mist does corrode metal very fast but a layer of blygold prevents this deterioration and preserves the internal and external components of a heat pump. The minimum rule of thumb is that if you can see the sea from the heat pump location then protection is needed. 

The available

Heat pumps are best sited in the open air away from enclosed spaces.  When the heat pump expels cold air the last thing you want is the retaining wall restricting circulation. 

The air source unit sits outside your property so it’s just the hot water tank that needs to be housed inside. If there is limited space in the house the garage or a small insulated shed is an equally good option. We work with a wide range of heat pump ready cylinders and often fit hot water tanks in confined spaces. We will work with you from survey stage to find the most suitable solution.

Existing hot water cylinder

As Harvest Cornwall is an MCS accredited company we need to ensure you have a heat pump and cylinder in line with these government standards. 

You will most likely find the cylinder you have currently is not heat pump ready. 

Air source heat pump installation

The correct installation of a heat pump is crucial to its efficiency and longevity.

We discuss each step of your air source heat pump installation with you prior to our start date to ensure all your needs are met.

We aim to make the air source heat pump installation process as smooth and stress-free as possible for you.

The life of a heat pump can be extended by using corrosion resistant coatings, micro strainers, magnetic cleaners and power flushing the system. 

Power Flushing

A power flusher will run until the central heating system is clean. It will stop any cold spots in radiators, help flow rates, improve efficiency and ultimately improve the life of your air source heat pump.


Although we very rarely get deep frosts here in Cornwall, glycol (antifreeze) is needed in the system in case a frost occurs. Without the right percentage of glycol there is a risk that the unit could be damaged by frost. Percentages of glycol are checked and recorded using a refractometer and should be tested annually. 

Future Accessibility

Access for serving and any maintenance should be as simple as possible. A heat pump should be serviced at least once a year, therefore easy access to strainers, lever valves, pumps and diverter valves must be planned at install stage.

Heat Emitters

Running at a lower flow temperature means that the balancing of the radiator/underfloor system becomes more important in order to efficiently heat your home.


Our highly trained engineers are not only qualified to industry standard but also trained specifically to install the brand of chosen heat pump. Further to this we are MCS Accredited, which means our work is regularly audited and held to the highest standard by an inspector of the governing body. 

Air Source Heat Pump Installation Cornwall

Air source heat pump maintenance

Maintenance and air source heat pump servicing should be carried out by an accredited and qualified installer.

Each manufacturer stipulates their own criteria for air source heat pump servicing, which must be met in order to carry out the service correctly. In many cases a yearly service is necessary to keep the warranty valid.

If your service is due, please contact us and we will arrange a visit.

Servicing Checklist

  • Glycol check – this is carried out with a refractometer and gives a reading of the percentage of antifreeze in the system.
  • Field settings – run through field settings to check they are all as per manufacturer’s instructions.
  • Strainer cleaning – we install micro-strainers with our heat pumps to prevent dirt entering the machine, this dirt collects in a strainer and can affect flow rates of the heat pump, it is a good idea to clean this out once or twice a year.
  • Coil cleaning
  • Safety checks on unvented cylinder
  • Immersion – check current and if it is still performing the legionella cycle.

Air source paybacks

An air source heat pump is a sure-fired way to reducing your reliance on fossil fuels. Although, you will still be reliant on electricity supply, this can be responsibly sourced from various renewables providers. And whilst the government’s Boiler Upgrade Scheme (BUS) is available why not take advantage and have your heat source heavily subsidised?

The BUS provides homeowners with a voucher to the value of £7500 paid from the government for having an air source heat pump installed instead of using fossil fuels. To be eligible for the Boiler Upgrade Scheme if you meet a few simple requirements:

  • You must be a homeowner or small business owner
  • Your property must be in England or Wales
  • The building must have been issued an EPC in the past 10 years

There are three valid paths to making sure your EPC is eligible:

  • Your EPC contains no recommendations for loft or cavity wall insulation
  • It contains one of these insulation recommendations, but you insulate your home between applying for the Boiler Upgrade Scheme and getting a heat pump installed
  • Your property has an EPC or insulation exemption – for example, this may be the case if you own a listed building.

More information on the scheme is available here: BEISOfgemEnergy Saving Trust7500

Air source underfloor heating

Optimal comfort is possible with underfloor heating for air source heat pumps if it is designed and fitted accurately.

The flow temperature required to run underfloor heating for air source heat pumps is typically around 35-45°C depending on how well your property is insulated.

We design the underfloor to a plan and a specification that will provide the right level of heat for the room. We produce a design for your approval before the date of install – it’s vital as areas under baths, showers, fitted wardrobes and fireplaces are avoided but need to be compensated for in other areas. All of the pipework will run back to a manifold at a destination agreed by you.


Stay within Budget

Underfloor heating is more expensive than a standard radiator system and for this reason many of our clients have underfloor downstairs and radiators upstairs. 

Most households spend the majority of their time downstairs in warmer temperatures of 21°C, whereas upstairs in bedrooms, design temperatures are slightly lower at 18°C. Radiators upstairs and underfloor downstairs can be a very cost effective and resourceful combination.

For more details on underfloor heating for air source heat pumps visit here.

Air source heat pump FAQs

If you can’t find an answer to your air source heat pump questions please contact us.

contact us

Drop us a quick message here and we will get back to you as soon as possible

Harvest Cornwall Ltd, Unit 6 Darbari Building,
Prow Park,Newquay,TR7 2SX

01637 808244 / 01637 854997