Air source heat pumps use refrigerants to absorb heat energy from the air outside and convert it into useable energy to heat our homes and hot water. For the last few years, R32 refrigerant has been widely used in heat pumps but, as heat pump technology continues to evolve, so too has the choice of refrigerants used in heat pumps with R290 emerging as an alternative. In this blog, we take a closer look at R290 refrigerant and its role in home heating.
Exploring R290: the next generation refrigerant for air source heat pumps
Air source heat pumps are a vital part of the UK's journey towards low carbon heating, helping households to reduce their reliance on fossil fuels. Central to every heat pump is a refrigerant gas which plays a key role in transferring heat, allowing the system to warm your home and supply hot water (you can read more about how air source heat pumps work here). While a number of refrigerants are used in heat pumps, such as R32, each has an impact on the environment, particularly in relation to ozone depletion and global warming potential (GWP).
Legislation and industry innovation are encouraging the move towards more environmentally friendly options and R290 - a natural refrigerant - is leading the way.
In this blog, we take a closer look at:
- What R290 refrigerant is
- The benefits it offers
- Its safety features
- How it compares to R32 refrigerant, used in the award-winning Aerona³ R32 models
- And how it is being used in the new Aerona 290 heat pump range.
What is R290 refrigerant?
R290 refrigerant, also known as refrigerant grade Propane, is a natural hydrocarbon composed solely of carbon and hydrogen. These naturally occurring elements classify R290 as a 'natural refrigerant'. Although it is industrially produced, its natural composition results in R290 refrigerant having significantly lower global warming impact compared to many other types of refrigerants.
What is R290 used for?
R290 refrigerant gas (which is the technical name for this natural hydrocarbon) is already widely used, for example in air conditioning systems and refrigeration, with its use in low carbon air source heat pump systems increasing as well. A hydrocarbon, R290 is non-toxic, odourless and has excellent thermodynamic properties which means that it can efficiently absorb heat energy from the air (when in a gas state) and transfer this to the wider heating system (when it cools into a liquid state). In addition to being highly energy efficient, R290 is also more sustainable compared to other refrigerants.
Inside a heat pump, R290 refrigerant is used in exactly the same way as R32 refrigerant with the refrigerant entering a cycle of changing from a liquid to a gas and back to a liquid. In the evaporator, where the air is drawn into the heat pump, the R290 refrigerant is exposed to the air where the refrigerant boils off to a gas and absorbs the latent heat energy from the air. As a gas, the R290 refrigerant is them compressed (in the heat pump’s compressor) where the heat content is increased further before the gas passes through the heat exchanger. At this point, the R290 gas condenses back to a liquid and it transfers its heat to the water in the heating system before re-circulating and repeating this cycle.
What are the benefits of using a R290 heat pump?
R290 refrigerant is not only a more environmentally friendly refrigerant but it also delivers a range of benefits to heat pump systems. From high efficiency performance to quiet operation, here are a few reasons why choosing a heat pump like the Aerona 290, Grant UK's R290 heat pump, makes sense for UK homes.
Environmentally friendly
R290 refrigerant has a Global Warming Potential (GWP) of just 3 which is significantly lower than traditional refrigerants such as R410a (GWP 2088) and R32 (GWP 675). Its low environmental impact supports both UK and EU targets to phase down the use of F-gases in favour of greener alternatives. Using a R290 heat pump will help reduce your home’s carbon footprint and support the UK’s transition to low-carbon heating.
Highly Efficient
With excellent thermodynamic properties, R290 enables a heat pump to capture heat energy and transfer it more effectively. This results in greater system efficiency. The Grant Aerona 290, for example, achieves an A+++ ErP energy rating at 35°C flow temperature and ideal for well insulated homes using underfloor heating or low temperature radiators. View the SCOPs for the Grant Aerona 290 range here.
Quiet Operation
As air source heat pumps are installed outdoors, noise levels are an important consideration. The Aerona 290 has been designed to operate with ultra-low noise levels, ensuring it operates quietly and does not disturb household occupants or neighbouring properties.
Discover more benefits of R290 heat pumps.
Is R290 refrigerant safe?
While R290 refrigerant is a flammable gas, it is safe to use provided it is safely handled and only by those suitably trained. As with any refrigerant, it should only be handled by trained professionals who understand how to work with it safely.
Designed with safety in mind
The safety of a R290 heat pump starts with its design. Air source heat pumps using R290 refrigerant, such as the Aerona 290, include several built-in features to ensure safe operation, including:
- Larger casings to safely house the R290 refrigerant in both gas and liquid form
- Specially designed compressors which minimise vibration and incorporate anti-leak features
- Integrated R290 leak detection sensors within the heat pump casing
- Safety enhanced components such as spark free sealed relays and ceramic fuses
- Wider clearance requirements during installation to maintain safe airflow and protection zones.
With specific handling and installation requirements, R290 heat pumps must be installed by qualified, trained heat pump professionals.
If you are interested in having a heat pump for your home use our Find an Installer tool to locate a heat pump installer in your area.
Comparing R290 and R32 refrigerants
As mentioned above, one of the key differences between R290 and R32 refrigerants is their Global Warming Potential (GWP).
- R290 has an extremely low GWP of 3
- R32, a F-gas, has a GWP of 675
This makes R290 a significantly more environmentally friendly option, aligning with the wider legislative changes which are supporting the move towards natural refrigerants that have less of an impact on the climate.
While R290 is more flammable than R32, both refrigerants are classified as having low toxicity levels. In terms of efficiency, both refrigerants perform well but R290 is considered to be more energy efficient. This is because R290 refrigerant evaporates at a slightly higher temperature compared to R32 and it has a lower condensing temperature than R32.
The infographic below highlights the key differences between R32 and R290 refrigerants, helping you to understand more about these heat pump refrigerants.
Grant UK, suppliers of air source heat pumps
Grant UK have been supplying air source heat pumps since 2010 with the Aerona 290 range being their fifth generation of heat pumps. Launched in the Autumn 2024, the Aerona 290 is an eye-catching heat pump which combines sleek aesthetics, quality design and the use of R290 refrigerant. To read more about this innovative range of R290 heat pumps, please visit our Aerona 290 product page.
This blog was originally published on 30th July 2024 and updated on 7th May 2025.