How to Choose the Right Pool Heat Pump for Your Swimming Pool?
If you’re still heating your pool with gas or a conventional electric heater, you’re spending more than you need to. A modern inverter heat pump can cut your pool heating costs by up to 80%, and in most cases it pays for itself within a few seasons. The catch is that buying the wrong size is an expensive mistake, and there’s more to choosing a heat pump than picking the cheapest one with a good brand name on it.
This guide covers what you actually need to know.
Start With How a Heat Pump Works
Unlike a gas heater, a pool heat pump doesn’t generate heat from fuel. It pulls warmth from the ambient air, amplifies it using a refrigerant cycle and transfers that heat into your pool water. Think of it as the reverse of how your fridge works. Because it’s moving heat rather than creating it, the energy efficiency is dramatically better.
That efficiency is measured by the COP, or Coefficient of Performance. A COP of 5.0 means you’re getting five units of heat for every one unit of electricity you put in. When you’re comparing models, COP at 15 degrees Celsius ambient temperature is the number to focus on. Anything above 5.0 is solid. Higher is better.
Getting the Size Right
Undersizing is the most common mistake buyers make. An undersized heat pump runs continuously, never quite reaches the temperature you want, and wears out well ahead of schedule. The rule of thumb is simple: when in doubt, size up rather than down. The extra capacity gets used, and your pool heats faster on cooler days.
Use your pool volume as the starting point for sizing:
| Pool Volume | Recommended Output |
|---|---|
| Up to 40,000 litres | 8 to 12 kW |
| 40,000 to 80,000 litres | 14 to 18 kW |
| 80,000 to 120,000 litres | 20 to 28 kW |
| 120,000 litres and above | Twin unit or 30 kW+ |
To work out your pool volume: length in meters x width x average depth x 1,000 = litres.
If your garden is exposed or you leave the pool uncovered overnight, go up a bracket. An uninsulated pool loses heat fast, and your heat pump needs to be able to keep up.
Four Things Worth Checking Before You Buy
Inverter models, sometimes labelled variable speed, adjust their output to match demand rather than running at full power constantly. Over a full season they typically use 20 to 40% less electricity than fixed-speed equivalents. If you’re planning to use this heat pump for more than one season, and you are, always choose inverter.
Noise is worth checking too. Cheaper units can be surprisingly disruptive, particularly if the heat pump is close to a boundary or a neighbour’s property. Look for a sound pressure rating under 50dB at ten metres. It’s not always listed prominently in the marketing but it will be in the spec sheet.
If you want to extend your swimming season into May and September, check that the unit maintains good efficiency down to at least five degrees Celsius ambient. Some entry-level models drop off significantly below ten degrees, which cuts your season short whether you like it or not.
Finally, warranty. A minimum of two years on parts and labour is the baseline. Better models carry three to five years, and every heat pump in our range at Blue Cube Direct comes with at least a two-year guarantee as standard.
If you ever feel unsure, you can always shoot over a message to find the right one for you!
What About Fitting It?
Most pool heat pumps connect to standard pool pipework using push-fit or solvent-weld fittings, and they need a dedicated electrical supply, typically 16 to 32 amps depending on the unit. The electrical connection needs to be done by a Part P registered electrician, no exceptions. If you need a recommendation for an installer in your area, our team is happy to assist you in the right direction.
Call us or use live chat on the website and we’ll give you a straight recommendation based on your pool size and setup.
Shop pool heat pumps at bluecubedirect.co.uk
Phone: 01234 783 569
Website: https://www.bluecubedirect.co.uk/