Decarbonisation: Exploring Exhaust Air Heat Pumps in UK Homes

To meet decarbonisation targets, virtually all homes in the UK will need to have low carbon heating systems.

While air source heat pumps (ASHPs) and ground source heat pumps (GSHPs) have proven effective tools in the transition to net zero, there are other options that may be better suited to some building types. Rick Clarke from NIBE introduces exhaust air heat pumps (EAHPs) and explains what installers need to know about this emerging technology:

Heat pumps have been rolled out to more than 250,000 UK homes in recent years, marking the start of the transition to low carbon heating. Air source heat pumps (ASHPs) make up the bulk of installations while others have opted for ground source heat pumps (GSHPs), which achieve higher efficiencies but generally require disruptive ground works to install.  

However, there is more to heat pump specification than ASHP vs GSHP. There are other types of heat pump that may be better suited to specific buildings. Exhaust air heat pumps (EAHPs) are one such example that will help the UK to decarbonise certain harder-to-treat properties. It’s important that installers are aware of all the options to ensure they are specifying high-performance heat pump systems for every application.  

What are EAHPs? 

Relatively unknown in the UK, EAHPs have been widely used in Sweden and other EU countries for several decades. The heat pump consists of a single unit situated inside the home that can deliver heating, ventilation and hot water, making it the ideal choice for properties that do not have outside space or where aesthetics cannot be changed.  

The latest models deliver high seasonal performance factors, at least SCOP4 and are some of the quietest household appliances on the market. At less than 50dB(A), EAHPs are even quieter than a refrigerator, ensuring minimal disruption and maximum comfort. As with other types of heat pumps, many EAHPs come with in-built monitoring and smart controls, and can be linked to home automation systems for full climate control.  

How do they work? 

Exhaust air heat pumps work in a very similar way to other types of heat pumps, but the key difference is rather than drawing heat from outside air or ground loops, they reuse energy from indoor air as it passes through an integrated ventilation system.  

The conversion of energy from the air to heating occurs in three different circuits: 

• Heating energy is extracted from the outgoing air and transferred to the heat pump. In some cases, outdoor air can also be used as a backup.  

• The heat pump increases the temperature from low to high in the refrigerant circuit.  

• The heat is then distributed around the house in the heating medium circuit, a closed circuit that transports the water to the integrated hot water heater and to radiators and/or heat emitters.  

What buildings do they suit? 

EAHPs are tailor-made for urban environments where conventional ASHPs may be unsuitable. Their compact design and noise-reducing features make them particularly suitable for flats, apartments, and densely packed inner-city dwellings.  

Currently, EAHPs are largely being installed by housing developers but there is huge potential for them to be used by individual homeowners and landlords. They can be used both in new builds and to replace existing heating systems, making them ideal for owner occupied apartment renovations, or for building upgrades as an alternative to heat networks.  

What do installers need to know about installation and designing these systems? 

EAHP installation should be carried out by experienced heating engineers with the relevant expertise, qualifications and training. Installers should hold an industry recognised level 3 heat pump qualification, however, this is just the first step. Manufacturers product training is critical to understanding new technologies, from specification and design to installation and commissioning, ensuring optimal performance and customer satisfaction.  

How do installers get trained on them? 

Currently, there is no qualification that covers EAHPs, training is delivered directly by manufacturers. As the first company to bring EAHPs to the UK market, we deliver specialist EAHP training free of charge to heat pump installers. Training covers installation procedures and familiarises installers with the unique operational features and benefits of EAHP technology. 

You can sign up to the webinar: here. 

Find out more at: www.nibe.co.uk