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Reduce Your Hot Tub and Swim Spa Energy Bills With the Latest in Air Source Heating

Air source heat pumps have been around for a while now but have recently started making their way into the hot tub and swim spa industry due to rising electrical costs, however it goes further than that, they also reduce the environmental impact of running a hot tub.

They reduce energy costs by up to 80% depending on atmospheric conditions.

We at Hot Tubs Rock have not jumped onto the early days bandwagon and started offering them without testing different models first on our own hot tubs.

We can now install the best quality models that we know are efficient and quiet meaning you get the absolute best experience out of your hot tub time.

How does an air source heat pump work?

They work by simply taking the air outside, passing it over a refrigerant coil which is then put under pressure by a compressor that raises the temperature and transfers that heat into the hot tub water. Our models remain efficient even down to -15 Celcius.

What are the benefits of running an air source heat pump over the electric heating element in my hot tub?

  • They use up to 80% less electricity
  • They heat the water at a much faster rate meaning on water changes you can drain, clean and usually be back up to temperature the same day (very useful for holiday lets with changeovers)
  • They reduce the environmental impact of a hot tub
  • In summer you get lovely cold air blown out of the front to cool you down
  • They can also be used in reverse to cool the water so you can have a cold tub and a hot tub in one (very useful for sports people)

Can they be fitted to any swim spa or hot tub?

Yes indeed they can! A modification is needed to the pipework inside the hot tub so that it diverts the water through the heat pump when the hot tub controls call for heat. The power is taken directly from the hot tub control box so no additional external wiring is needed.

What happens to my electric heater inside the swim spa or hot tub?

It remains in place as we still need it’s sensors to tell the circulation pump when to start and kick the heat pump in but it’s either disconnected from power or we can install a changeover switch so you can select air source or electric.

What are the actual real world savings?

I’m glad you asked!

I have comparisons here over two different types of heat pump that I tested on a showroom hot tub with water temperature at 40 degrees and air temperature between 0 and 8 degrees (this was in January). I have tested more since and continue to do so, so I’ll have more data very soon.

Cost per day

What is the difference between ON/OFF and Inverter heat pumps?

The ON/OFF heat pumps tend to be cheaper as the technology is much simpler as they’re either on full power or off.

The inverter models tend to cost a bit more to buy but offer more savings as they can change the amount of power they use depending on heating demand, water temperature and air temperature so if they don’t need to come on full power then they won’t.

Are there downsides to installing a heat pump?

There are far more positives to installing a heat pump than negatives but we like to be completely transparent with our customers.

  • Initial cost is quite high – you need to work out how much you’re using now compared to what you could save and how quick the payback would be, we have some people that have estimated 1 year based on use and their tariff and others 5 years so just work out what’s right for you.
  • They are fairly sizeable units and to minimise heat loss from the external pipework and so the current circulation pump can cope with the distance they need to be as close to the hot tub as possible. They also need a lot of space around them for air flow so can’t be blocked in behind fences or hedges otherwise their efficiency will suffer.
  • There is a slight noise of the fan running when the pump kicks in but on the models we’ve chosen it’s kept to an absolute minimum (no jet aircraft impersonators here)


I believe I’ve covered everything in an easy to understand way but please message us if you have any further queries or don’t fully understand my ramblings!

In short we believe air source heat pumps to be the future of hot tubs and with technology improving all of the time and manufacturers constantly innovating ( there’s talk of them being built into some hot tubs) it will mean running a hot tub will be more affordable for more people as we truly believe in this modern world that they are a necessity rather than a luxury due to the benefits they bring both mentally and physically.

Thank you for reading
Joe (the ape like technical one)