Pool Heaters & Chillers: reviews & buyer's guide

Why heating decides how much a pool gets used

An unheated pool is genuinely comfortable for only part of the year, even in a warm climate. Cooler months and cool snaps leave the water too cold to enjoy, and a pool nobody wants to get into is an expensive ornament. Heating closes that gap, and it is often the difference between a pool used a few times a season and one used most of the year.

The heating question has two parts: which type of heater, and how to run it efficiently. Get both right and a heated pool is a year-round pleasure at a reasonable cost. Get them wrong and heating becomes a bill that makes you ration the comfort you paid to build.

Heat pump versus gas heater

A heat pump does not create heat; it moves it. It draws warmth from the surrounding air and transfers it into the pool water, using electricity only to run the process. Because it moves heat rather than generating it, a heat pump is highly efficient and inexpensive to operate. Its trade-off is that it works best in mild and warm air temperatures and heats the pool gradually rather than instantly. Many heat pumps carry the ENERGY STAR label, and certification can be checked at energystar.gov.

A gas heater burns natural gas or propane to heat the water directly. Its strengths are speed and independence from air temperature: it heats a pool, or a spa, quickly, in any weather. Its weakness is running cost, because every hour of heat has a fuel cost attached, and that cost rises with fuel prices. A gas heater suits owners who want fast, on-demand heat, especially for a spa, while a heat pump suits owners who want efficient, steady, season-extending warmth for the pool.

What to look for in a pool heater

For a heat pump, look at the efficiency rating, the heating capacity relative to your pool size, the build quality of the components for a long outdoor life, and quiet operation. For a gas heater, look at the heating output, the efficiency rating, and durable, corrosion-resistant internal components. For both, a heater that integrates with pool automation is far easier to run sensibly, and correct sizing to the pool is essential.

Pairing any heater with a pool cover transforms its economics. A cover holds heat in overnight, so the heater works far less to maintain temperature. Heating without a cover is heating water and then letting much of that heat escape into the night air.

The other half of comfort: pool chillers

In a hot climate, the temperature problem is not always that the water is too cold. Through the peak of summer, a pool can heat up so much under relentless sun that it stops being refreshing. Water that has climbed into the high eighties or beyond feels more like a warm bath than a cool dip, and on the hottest days a pool can fail to do the one thing it is most wanted for: cool you down. That is the problem a pool chiller solves.

A pool chiller is a unit that removes heat from the pool water, the reverse of what a heat pump heater does. Many work on an evaporative principle, drawing pool water through a chamber where air flow evaporates a small amount of it and carries heat away, returning the rest cooler. The result is a pool held at a genuinely refreshing temperature even at the height of summer. For a pool in a hot region, a chiller can be as valuable as a heater is in a cool one.

Some equipment combines both functions. Certain heat pumps are heat-and-cool units, heating the pool in the cooler months and cooling it in the hottest, giving an owner true year-round temperature control from a single piece of equipment. For a pool that suffers both a cold season and a punishingly hot one, a heat-and-cool unit, or a heater and a dedicated chiller together, delivers comfortable water every month of the year.

How WETYR Pools helps

WETYR Pools sizes, supplies, installs, and services pool heaters and chillers, and we design solar pool heating for owners who want the lowest possible running cost. We help you weigh a heat pump against a gas heater, decide whether a chiller or a heat-and-cool unit is worth it for your climate, and integrate the equipment with automation and a cover, so the water is the temperature you want it, every season of the year.