Although not every type of heat pump can cool a home, air to air heat pumps can. But, just because the option is available, you still need to establish if it's the right version for your home.
It's even more important to investigate further if you're considering a heating system upgrade as part of your home renovation plans. What may work in a new self-build, where everything is being designed from scratch, might not be as simple when modernising an older property.
So what do you need to consider if you're seeking a solution that will both cool and heat your home?
Choosing the right type of heat pump
Although the term heat pump is used in a generic way, there are a number of different types of heat pump and only two of them can cool a home.
And, while the answer to can a ground source heat pump cool a house is simply yes, it's not quite as straightforward when it comes to air source heat pumps.
Not all air to water heat pumps can cool a house, whereas air to air heat pumps do have the functionality to provide both hot and cold air flow.
But, this also comes with a caveat. Not many air to air heat pumps can also heat water, which as we'll come onto explain, means it might not always be the best solution if you are looking for a heat pump that can do it all.
How do heat pumps cool a house?
If you're weighing up heat pumps vs air conditioners, the simple way to explain it is that an air to air heat pump is essentially an air conditioning unit that works in reverse.
"An air to air heat pump operates in a similar way to a fridge," explains Hamid Salimi, residential product manager at Daikin UK. "It exchanges energy from the outdoor air, and air to air heat pumps cool the space by the process of refrigerant evaporation and condensation.
"In heating mode, an air to air heat pump absorbs energy from the outdoor air and releases it as heat through the indoor unit. In cooling mode, the process is reversed: heat is extracted from inside your home and released outside," he explains.
Andy Pattison, previously head of renewables at BOXT confirms that, "many people don’t realise is that air conditioning units are technically air to air heat pumps, so while in warmer months they remove heat from inside and release it outdoors, in cooler months they can reverse their operation to keep you warm.
"However, not all air source heat pumps can do this," he warns, "so it’s important to check the make and model carefully before making your choice. If you're uncertain or want to know more, the company you choose for installing your air source heat pump should guide you through your options when providing your initial fixed quote.”
Hamid Salimi has a BSc and MSc in mechanical engineering and has worked with Daikin for over 13 years in various roles such as product applications, HVAC design and currently as a Product Manager leading a team of product specialists covering all aspects of residential renewable heating.
Andy Pattison was Head of Renewables at BOXT and has over 40 years of experience in the heating and renewables industry.
Air to air or air to water?
Although air to air heat pumps can cool a house, as mentioned, it's not impossible for some air to water heat pumps to cool a room too. Some have a reverse function, which means they can also provide colder temperatures. But, they may not be the best solution if you are considering upgrading your current heating system, warns Andy Pattison.
"While both types of air source heat pumps are technically capable of offering cooling, we would typically recommend that an air to water heat pump should only be considered for cooling if it’s being installed in a new-build home where it can be factored into the building design."
Why? "Because this type of heat pump requires correctly installed underfloor heating or fan coil units, and wouldn’t work with the radiators that most UK homes have." Air to air heat pumps on the other hand, "are much simpler to retrofit and can offer both heating and cooling in one or more rooms in your home," he says.
But, don't forget this important point. If you are assessing if your home is suitable for an air source heat pump, you'll also need to take your hot water supply into account, as well as your heating and cooling needs.
While air to air heat pumps have historically not been designed with hot water supply in mind, companies are recognising the need for solutions that cater to more than just heat. And with rising temperatures becoming an issue for us all, the juggle between hot and cold is increasingly becoming part of the discussion.
Companies are starting to recognise the growing need for products that fulfil a number of different needs, with Daikin's all-in-one system, Multi+ a prime example of the changing face of heating systems.
"Offering heating, cooling, air purification and domestic hot water for small and mid-size homes, it connects to five units and one domestic hot water tank," explains Hamid Salimi. "The unit is compatible with a 120 and 230-litre tank and a wide range of indoor units. The outdoor unit is compact, which means that it is ideal for small outdoor spaces such as balconies and terraces."
But, with a limit still on the space it can both heat and cool, if your home is larger, you may still find it makes more sense to install air conditioning and ensure you have plenty of other measures in place to keep a room cool too.
FAQs
What radiators do I need for an air-to-water heat pump that cools?
So why can't you just use a standard radiator with an air-to-water heat pump that does cool? Nick Duggan, MD of the Radiator Centre explains more.
"Fan-assisted radiators designed for use with heat pumps can provide both heating and cooling when connected to a compatible system. Rather than relying purely on natural convection like traditional types of radiator, they use low-energy fans to draw air across a heat exchanger, significantly improving heat transfer.
"In heating mode, warm water from the heat pump is circulated through the radiator to provide even, comfortable warmth at lower flow temperatures," he continue. "In cooling mode, chilled water passes through the unit, allowing it to absorb heat from the room and gently reduce indoor temperatures."
While the process of how they work sounds simple enough, is retrofitting them easy? Is it more complicated than changing your current radiators to larger ones in the same style?
It's not necessarily more complicated says Nick, but there are a couple of extra things to think about.
"Like standard radiators, fan-assisted radiators still connect into the same water-based heating system, so the basic installation isn’t any more complicated when you’re upgrading to a heat pump.
"The main difference is that these units need electricity as well, because they use small fans to help move air through the radiator. That just means an electrical connection is required for each unit, which isn’t needed with standard radiators," he explains.
"Plus, if you want to use the cooling function, the system also needs to be set up for it from the start. That means the heat pump must be able to provide cooling, and the installer will need to make sure everything is designed to manage moisture in the air safely.
"In practice, when it’s planned properly as part of the heat pump installation, it isn’t significantly more complicated," he notes, "it just needs a bit more coordination between the heating and electrical design."
It's also worth clarifying that you may need to allocate more to your heat pump costs budget if you do opt for radiators that can cool. They are slightly more expensive confirms Nick, "mainly because they include built-in fans and controls, and because they’re designed to work efficiently with lower temperature heating systems like heat pumps, while also offering cooling when needed.
"However, they can add real value by combining heating and cooling in one system," he emphasies, "which in many homes, can remove the need for separate air conditioning costs, helping to balance out the initial uplift in price over time."
Nick has over 20 years of experience in central heating and radiators, leading the team at one of the UK's largest independent suppliers.
So, while the answer to can a heat pump cool a house can be yes, it's certainly a decision that needs plenty of consideration and discussion with your supplier before you make any final choices.
It's likely that air source heat pump costs will be a contributing factor when picking your system, as will whether you are renovating or self-building.
And, if it's the latter, make sure you are also designing your home to prevent overheating, so that whatever system you do install is able to function effectively.
