Heat Pumps

Hot Tub & Swim Spa Heat Pumps

A heat pump is the smartest way to cut hot tub running costs in the UK. Instead of generating heat like a standard electric element, it moves heat from the air into your water, delivering several units of heat for every unit of electricity it draws — especially in mild-to-cool conditions. From £1,799.

The range

  • Best value inverter — the iNHEAT SpaLine 7kW (£1,799, heating & cooling, Wi-Fi, runs to -25°C) and the plug-and-play Gecko (5/7.5kW, £1,899).
  • Ultra-quiet — the AQUARK Mr.Silence (7–21kW, Mitsubishi inverter, titanium exchanger, from £1,999) and the full-inverter Inverboost PBS (7.5–21.5kW, from £1,899).
  • High output / cold-weather & swim spas — the Inverboost UX (11/14/17kW, from £2,700) and top-discharge Inverboost VX (17kW, £4,799) for larger volumes and year-round use.

What to check before you buy

  • Your water volume — larger tubs and swim spas need higher kW for fast heat-up.
  • How you use it — weekends-only vs most nights changes what "best value" looks like.
  • Placement — heat pumps need airflow clearance and sensible positioning.
  • Power supply — most need a dedicated electrical supply; check with your electrician.

Unsure on size? Message us your hot tub model (or water volume in litres) and we'll recommend the right unit. For the full picture, see our hot tub running costs guide.

Heat pump FAQs

How much can a heat pump save vs a standard heater?

Because a heat pump moves heat rather than generating it, it delivers several units of heat per unit of electricity (its COP), where a standard element is always 1:1. The exact saving depends on your tub, usage and the weather, but heat pumps are consistently the cheapest way to keep a tub warm across a UK year. See our running costs guide for real figures.

What size heat pump do I need?

It's driven by water volume and how cold you run. As a rough guide, smaller tubs suit 5–7kW, larger tubs and most year-round users want 9–14kW, and swim spas or very large volumes need 14kW+. Send us your model or litres and we'll size it for you.

Are heat pumps noisy?

Modern inverter units are quiet — the AQUARK Mr.Silence and Inverboost models are designed specifically for low noise, ramping output up and down rather than cycling on and off. Sensible placement (airflow, not against a bedroom wall) keeps them unobtrusive.

Can a heat pump heat a swim spa?

Yes — choose a higher-output model (the Inverboost UX/VX range) sized for the larger water volume. Swim spas hold far more water than a hot tub, so they need more kW to heat and hold temperature efficiently.

Do heat pumps work in winter?

Yes. Efficiency (COP) drops as the air gets colder, but inverter units like the iNHEAT SpaLine are rated to operate well below freezing. For deep winter, size up slightly so the unit maintains temperature comfortably.