How much energy can you save with an air source heat pump

Heat pump systems – what exactly are they? How do they work? And why are more and more people starting to use them in favour of traditional heating systems? In short, source heat pumps collect thermal energy from an external source (the air, water or ground) before concentrating it for internal use. Why the sudden rise in popularity? Well, aside from the Government grants available to homeowners choosing to make the transition to a heat pump system this is largely due to heat pump efficiency and energy sustainability.

In this blog we’ll look in more depth at how source heat pumps work, how efficient they are in reality and look at the potential savings in energy costs in comparison with traditional gas boilers. As an MCS certified installer of source heat pumps we’re perfectly placed to help you make the transition – whether you’re a developer, architect or homeowner. To find out more about our installation service, or to find out more about how your build could benefit from this renewable energy source call us today on 01403 253439.

What is an air source heat pump?

Air source heat pumps (ASHP’s) are one of three types of source heat pumps, the other two being ground source heat pumps (also known as geothermal pumps) and water source heat pumps.

Essentially, a heat pump absorbs external thermal energy which is then vapour compressed via a heat exchanger in a process similar to that of a refrigerator or air conditioner in reverse. This process warms the water which runs through your radiators and /or underfloor heating.

There are two types of ASHP’s – monoblocs and split systems. Monobloc systems house all of the components in an external unit which runs the pipes leading to the central heating system and hot water tank. In a split system components are separated into external and internal units. Split source systems are typically more expensive to install than monobloc systems but offer a range of benefits including a reduction in noise and a lack of requirement for a separate hot water storage tank.

How efficient are air source heat pumps?

Whilst the ground source heat pump takes the crown for efficiency the ASHP is far from a million miles behind. Exactly how efficient they are however can be difficult to say, and is dependent on a number of factors.

Heat pump efficiency is calculated by measuring the amount of energy input versus the amount of energy output. This efficiency is described as the Coefficient of Performance (CoP). To put it simply, if an ASHP uses 10kW of energy (electricity) and produces 40kW of energy (heat) the CoP efficiency is four.

Over a full heating season the average efficiency of an ASHP is described as the Seasonal Coefficient of Performance (SCoP) or Seasonal performance Factor (SPF).

The best systems operate at an efficiency of around 4.5 CoP, however CoP values can lead to unrealistic expectations of heat pump performance as they only describe the efficiency of peak performance. SCoP figures offer a more realistic picture of heat energy efficiency.

Are heat pumps more efficient than gas boilers?

When it comes to energy efficiency heat source pumps out perform gas boilers in almost every circumstance. Despite considerable advances over recent years gas boilers typically operate at an efficiency not exceeding 95%. In comparison, heat source pumps typically operate at an efficiency of between 300-400%.

ASHP’s typically operate with a CoP rating of 3.2 in circumstances where the external temperature measures in excess of 7°C. This performance means that the system is operating at 320% efficiency; ie. for every 1kWh of electricity required to operate the system it produces 3.2kWh heat.

Can you save energy with an air source heat pump

Potential energy savings

The potential energy savings and carbon emission reductions resulting from the transition to an ASHP are dependent on a number of factors. First of all it is worth noting that there are significant differences between the efficiencies of the lowest and highest performing pumps. We are approved installers of Mitsubishi ASHP’s – a tried and tested brand with a reputation for quality – whose units are among some of the quietest available on the market.

It is mandatory for all ASHP’s to be labelled according to their efficiency. The most energy efficient units are colour coded dark green, whilst the least energy efficient units display a red label.

Potential cost savings

In much the same way, the potential cost savings associated with a transition to an air source heat pump may vary considerably. Those choosing to replace an old and outdated boiler system, or completely gutting and restoring a property, or building a new property stand to benefit considerably from the switch. Those seeking to replace relatively modern gas boiler systems are likely to see lower cost savings. ASHP’s are not suitable for all types of properties and poorly insulated buildings will experience very little benefit.

Government grants

Boiler Upgrade Scheme

The RHI scheme was replaced by the Boiler Upgrade Scheme in March 2022. The scheme provides capital grants for the installation of heat pumps and biomass boilers in homes and some commercial dwellings.

Install air source heat pumps at your development

If you have any questions regarding the benefits of air source heat pumps, or would like to know more about sustainable energy sources we’d love to hear from you. Our friendly team of energy experts are on hand and available to answer any questions you may have. Just give us a call on 01403 253439 to find out more about how you could reduce your carbon footprint whilst creating financial savings.

Our air source heat pump installation packages include:

  • Full site survey and bespoke design of the system
  • Supply of the air source heat pump, accessories, DHW cylinder & buffer tank (if required)
  • Heat loss calculations
  • Performance estimate and cost analysis
  • Commissioning of all equipment
  • Certification for the domestic Renewable Heat Incentive/Government Grant
  • MCS compliance certificate
  • Heat pump installations, if required


Posted in Sustainability, Energy.