What Is an Air Source Pump and Should I Buy One?

With energy bills on the rise, many of us will be looking for ways to keep our electricity usage as low as possible.

While our guide to hot tub running costs has a few tips to reduce your energy usage, one of the best ways to slash costs is with an Air Source Pump. Not only can it cut your hot tub energy costs by up to 70% (for holiday parks, this means recouping your investment in around 18 months), but it’s also a more eco-friendly way of running your spa. 

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How do they work?

In this case, the clue is in the name – Air Source Pumps take thermal energy from the air and use it toheat your hot tub’s water, producing four times more heat energy than they use in electricity. By using inverter technology, they can maintain temperature using a lower current, and heat water regardless of the outside air temperature, generating up to 5kw of energy for every 1kw of electricity used. 

Compared with regular heat pumps, these inverter-driven pumps automatically optimise the refrigerant flow rate by varying the speed of both the fan and the compressor.

This inverter technology also means the fan doesn’t need to run often, as it keeps the temperature consistent. However, when it does run, it’s super quiet at around 35db (for comparison, a whisper is 30db).

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Should I get one?

If you operate a holiday let, then reducing your carbon footprint it going to be key in the coming years, and an Air Source Pump will help with this. It will also ease the cost of running multiple spas – potentially saving you thousands in energy bills. If you have a hot tub for your home, then the energy savings will no doubt be welcome – especially in the current climate. Depending on usage, your Air Source Pump could have have paid for itself in as little as 18 months. 

They’re also quick to heat, with water temperature of around 12C taking well under four hours to reach 40C, which is especially convenient for holiday cottages wanting to keep changeover times low.

Example cost and time

When put to the test, below is an outline of how long it took the DuraPRO Air Source heater to heat the water in a hot tub, and the kilowatt cost:

Temperature: Heating Water from 10C to 38C

Start time: 9am with an ambient air temperature of 12C and a water temperature of 8C.

Start reading: 295

End reading: 303

Time taken to heat the water from 10C to 38C: 3 hrs 40 minutes

Electricity usage: 8kWh, at a cost of £1.60 (based on 20p per kWh unit cost)

Equivalent 4kw electric heater cost: £6.40

Which Air Source Pump is right for you?

Take a look at our Air Source Heat Pump ranges below to see which is right for you.


7KW – VIAN Air Source Heat Pump – £2,195

Best for: domestic hot tubs from 1,000 – 1,500 litres

Suitable for small to medium domestic hot tubs, this heat pump is ideal for models such as the American Whirlpool 480 or the Marquis Spas V84L. A full DC inverter heat pump, the 7KW – VIAN Air Source Heat Pump is a feature-packed, high-performance model that’s capable of operating down to -10°C ambient temperature.


CAPACITY 100-20% power
Plus 27C KW Out 7.21 – 1.6 / COP @ 6.4 – 16.9
Plus 10C KW Out 4.77 – 0.95 / COP @ 4.35 – 6.08
Capacity kW 27/24 (DB/WB) 1.5KW – 7.21KW
Max power draw 0.09KW – 1.09KW
Power supply 220-240 V 50 Hz Single Phase
Ambient temp operating range Minus 10C to Plus 43C
Heating range 15C to 40C
Ability to cool water Yes
Sound at 1m dB 32 – 45
Required flow rate 3.1 m/hr (51.6 l/min)
Wifi Yes
Dimensions (mm) 910 w x 355 d x 620 h

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DuraPRO come in a variety of sizes, and are able to heat water to 40C – even in temperatures of -15C. We stock a range of sizes of DuraPRO Air Source Pumps – the 12, 17, 21 and 25 – with specs outlined below. To ensure you make an informed choice, though, give us a call or book a showroom visit. 

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Product dimensions

DuraPRO-12 – recommended for hot tubs.

DuraPRO-17 – recommended for larger hot tubs and swim spas.

DuraPRO-21 – recommended for larger hot tubs and swim spas.

DuraPRO-25 – recommended for larger hot tubs and swim spas.

Product information

While the main reason to buy one is the cost savings and efficiency, here’s everything else you can expect from a DuraPRO heat pump, including:

    • A 5” colour touch screen display
    • Easy-to-use, lockable digital control panel
    • Soft start
    • Low noise, multi-speed fan
    • Automatic hot gas defrosting
    • Titanium heat exchanger
    • Ability to operate in air temperatures as low as -15 °C
    • Capable of heating and cooling all year round
    • Comes with a winter cover
    • A two-year warranty on parts and labour

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For information or advice on buying an Air Source Pump, hot tub or swim spa, or to book a showroom visit, contact us online or give us a call on 01974 241 642. Our friendly team will be happy to help. 

Step-By-Step Guide to Hot Tub Maintenance 
Hot Tub Accessories Guide