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Home : Technologies : Air Source Heat Pumps

Air Source Heat Pumps (ASHP)



Greenheat Renewables Ltd are experts in the installation of ASPH technologies with over 12 years’ experience.  We have designed and installed heat pump solutions for all types and sizes of domestic and commercial properties from new builds to period and listed properties, and numerous industrial buildings. 


No two projects are exactly the same, and each installation will start with a comprehensive assessment of the property including comprehensive heat loss calculations.  We will meet with you to understand your project requirements, and work with you to build a bespoke solution for all your heating requirements. 

How it works

An air source heat pump (ASHP) is a system that transfers heat from outside air to inside a building, or vice versa. Under the principles of vapor compression refrigeration, an ASHP uses a refrigerant system involving a compressor and a condenser to absorb heat at one place and release it at another. They can still extract heat when air temperatures are as low as -15c.  This heat is then used for heating radiators, underfloor heating systems, or warm air convectors, as well as providing hot water.

There are two types of ASHP – air to air and air to water.  The selection will depend upon the type of heat distribution system you need. 

Air-to-water heat pumps absorb heat from the outside air, and transfer the heat to water.  An air-to-water system distributes heat via your wet central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler system would. This makes them more suitable for underfloor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.  


Air-to-water heat pumps are the most common model in the UK. Only Air to Water heat pumps are eligible for the RHI scheme.  Please see Grants for further information. 


Air to air pumps require a warm air circulation system to move the warm air around your home.  They do not provide hot water and are not eligible for the Governments Renewable Heat Incentive (RHI) scheme. 

ASHP are likely to lower your energy bills particularly where they are replacing conventional electric heating.  Unlike gas or oil boilers heat pumps deliver heat at lower temperatures over much longer periods, therefore radiators may not feel as hot to touch.  

Things to Consider

There are a number of factors to consider in any ASHP project including:-

  • An ASHP installation does not have the cost of laying the ground collector or drilling the borehole therefore will usually have a lower installation cost.

  • Insulation - an ASHP will be more efficient in a well insulated property.

  • An ASHP may require a building warrant, depending on the area that you live in.  This is due to the ASHP being located outside. 

  • Less space is required for an ASHP than a GSHP, however the pump must have a minimum of 1m free space in front to operate effectively.

  • An ASHP requires electricity to operate.  Adding Solar PV technology to the system can improve the efficient and increase cost savings. 


We can help you assess whether an ASHP is the best solution for your project and provide you with costings and estimated savings from the installation.  

An ASHP system

ASHP Diagram.png

Grants and Subsidies


There are a number of different grants and financial incentives available from the Government to help with the cost of installing this technology. 


The grants available will depend on where you are based (there are different schemes depending on whether you live in Scotland or the wider UK).  There are also different schemes for domestic and commercial installations - See Grants.

How Greenheat can help

Greenheat Renewables can help you assess whether an ASHP is the best solution for your project. 


We can provide you with more detailed information how the technology works and discuss the various options for maximising the efficiency of the system.

Our design engineer can conduct an initial site visit (or can discuss your project over the phone) and provide you with a heat loss assessment and an indication of the size of pump and system you may need.

We can also provide you with estimated cost savings form the new system and potential income from the RHI scheme.  

We have undertaken a huge variety of projects installing ASHP systems, both domestic and commercial and we thrive on finding solutions which are right for you.

If you would like more information on ASHP or would like to have a more detailed discussion about your project please contact us on (01361) 315000 or send us an e-mail to  Our design engineer will be in touch to answer your query.   

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