Search for the best pool heat pump and you will find a dozen lists, most of them written by people who have never installed one, and most of them ranking units in an order that has more to do with affiliate arrangements than performance.
The honest position is that there is no single best unit, because "best" depends on your climate, your pool and how you swim. What there is, though, is a set of criteria that reliably separate a good machine from a mediocre one.
Here is how to judge the best pool heat pumps for yourself, rather than trusting a list.
Criterion one: efficiency where you actually live
Every brochure leads with a coefficient of performance figure. Almost none of them lead with the conditions it was measured at.
COP is a ratio of heat output to electrical input, and it is enormously sensitive to ambient air temperature. A peak COP measured at a warm ambient temperature is a real number and a nearly useless one, because it describes the machine's single most favourable operating point.
What to ask for instead: performance across a range of ambient temperatures, particularly at the cool end of the conditions you will operate in. A unit with a slightly lower headline figure that holds its performance as the air cools will cost you less across a season than one with a spectacular peak number that falls away.
Compare like with like, at the same conditions, or you are not comparing anything.
Criterion two: genuine variable speed
The word "inverter" is on nearly every premium unit sold in Australia and it describes at least three different technologies.
On off units run at one speed: maximum. They overshoot, switch off, drift down, and fire back up.
Stepped inverters have a handful of fixed speeds. Better, but still cycling between fixed points rather than matching demand.
Full inverters vary compressor speed continuously across the range.
This matters because heat pumps are most efficient running slowly, and most of a heat pump's working life is spent holding a temperature rather than heating from cold. A unit that can sit at low output indefinitely spends most of the season in its efficient band. One that cannot, does not.
Ask the direct question: is compressor speed continuously variable or stepped? Any supplier who cannot answer plainly has answered you anyway.
Criterion three: it holds temperature, not just reaches it
Reaching a set temperature is easy. Holding it steadily is where the difference shows.
On off units produce a sawtooth: overshoot, drift, overshoot. The water is rarely at the temperature on the display. A variable speed unit holds a much flatter line, which you feel every time you get in.
Temperature stability is rarely advertised and it is one of the most noticeable differences in daily use.
Criterion four: build quality where it counts
Two components determine whether a unit lasts.
The heat exchanger. Pool water is chemically aggressive, particularly when chemistry is not perfectly maintained. Ask what it is made from and what the warranty says about water balance.
The compressor. Thermal cycling wears mechanical components. A unit that runs steadily at part load cycles far less than one slamming between full power and off, which is a durability argument as well as an efficiency one.
Also worth asking: what is the casing made from, and how does it handle a coastal environment? Salt air is unforgiving on equipment sitting outside year round.
Criterion five: support that exists in Australia
This is the criterion nobody weighs at purchase and everybody weighs in year five.
Is there local parts availability? Is there a service network? Is there a phone number answered by someone who knows the product?
A cheaper unit from a brand with no local presence is a gamble on nothing going wrong for a decade. Heat pumps are long term equipment and they do occasionally need attention.
Criterion six: correct sizing beats a better badge
Worth saying plainly, because it undercuts the entire premise of ranked lists.
A correctly sized mid range unit will outperform an incorrectly sized premium one, every time. Undersize and it never reaches temperature. Oversize and you have overpaid, and with on off technology you have introduced short cycling.
The best heat pump is the one that fits your pool volume, your target temperature, your climate and your cover habits. That is not a product you can pick off a list.
Request a free personalised pool heat report and the sizing question gets answered properly.
What to be sceptical of
A single headline COP with no conditions stated. Meaningless without context.
"Up to" figures. Up to is doing all the work in that sentence.
Ranked lists with no methodology. If the article does not say how it judged, it did not judge.
Guaranteed running costs. Nobody can guarantee that. It depends on your climate, your target temperature, your cover use and your electricity tariff.
Comparisons between units at different test conditions. Extremely common and completely invalid.
Frequently asked questions
Is a more expensive unit always better?
No. It is often better built and better supported, but the wrong size in a premium badge still underperforms the right size in a mid range one.
How do I compare two units fairly?
Get performance figures at identical ambient conditions, confirm whether each is a full or stepped inverter, check minimum operating temperature, and compare warranty terms including what voids them.
Does brand matter?
Mostly through support and parts availability rather than the badge itself.
Should I buy on COP alone?
No. COP at your operating conditions is one criterion among several, and sizing matters more than any of them.
What about running costs?
They depend on your climate, target temperature, cover use, running hours and tariff. Any figure quoted without those inputs is a guess.
Judge it yourself
Ask the six questions above of any supplier and the field narrows quickly.
Have a look at the Evo Force-i Pro, browse the full pool heater range, or request a free personalised pool heat report.
