How to size a cold plunge chiller

The submersible pump is what makes this the bathtub answer. A chiller normally needs a tub with inlet and outlet ports; a bathtub has neither. Dropping a pump into the water and running two hoses over the rim is inelegant and it works, and it is the cheapest route to a cold plunge for anyone who cannot give up floor space for a tub at all.

Six hundred watts is eleven cents an hour at full draw, comfortably mid-range here. The 79-gallon rating is a good match for a standard bathtub, which holds somewhere between 40 and 80 gallons at plunge depth.

The reusable metal mesh filter rather than disposable cartridges is a genuine running-cost detail that gets ignored because it is not electricity. Cartridge filters are a recurring purchase; a rinsable metal screen is not, and over a year that difference is larger than the difference in power draw between two chillers.

An availability note, because we said we would keep it current: this listing went to "Currently unavailable" on 2026-09-09 and we routed its buy link to a search rather than to a product nobody could add to a cart. Re-checked on 2026-09-12, it is back in stock with a buy-box offer, so the link points at the listing again.

The disclosure worth buying this for is the sizing band. Every other chiller here publishes one volume figure and leaves you to guess whether it is a comfortable rating or a ceiling; this listing publishes both, recommending 79 to 105 gallons and naming 132 gallons as the maximum limit. Size to the band rather than to the ceiling - a unit run at its stated maximum is a unit running continuously - and the sizing method is the same one we use everywhere else on this site.

It also arrives as a complete loop rather than a box that needs parts. The listing names a built-in filter pump, a submersible pump for tubs with no ports, insulated hoses, quick-connect fittings and sealing tape, and describes the filter as something you rinse once a week rather than a cartridge you replace. That is a recurring-cost detail rather than a feature, and it is the same distinction we draw across the whole category: a rinsable screen costs nothing ongoing, a cartridge is a subscription.

The gaps are real and they cost it points. No rated wattage is published anywhere on the listing, which means there is no honest running cost for this unit - not an estimate, not a range - and the electrical-fit and cost-to-run components of its score have no input and score zero. No warranty term is published either. And no decibel figure: the one listing in this category that published one has gone, so no chiller on this site publishes a noise figure at all, which is worth knowing if the box has to live near a bedroom.

Two hundred and thirty gallons at 37 F is the largest published capability in this roundup, and it is the only unit that plausibly pairs with the 216-gallon tubs elsewhere on this site. Sizing a chiller under its tub is the most common expensive mistake in this category: an undersized unit runs continuously, never reaches setpoint, and costs more in electricity than the right one would.

The wattage is not published, which on a 1 HP unit is a real gap. The TURBRO in this roundup is also 1 HP and publishes 1,030 W, so the order of magnitude is not a mystery - but we are not going to attribute another manufacturer's figure to this one, so the cost-to-run component scores zero and the score reflects it.

At 83 pounds this is by far the heaviest chiller here, which is why the caster wheels are a specification rather than a nicety. It is also why the external filter matters: a 20-micron cartridge you can change without moving the unit is the difference between maintaining it and not.

This is what a complete chiller spec sheet looks like: 1,030 W rated power, 9,553 BTU/h maximum cooling capacity, AC 110 to 120 V at 60 Hz, a 36 to 86 F range, and a stated cooling time with the starting temperature named. Every one of those is checkable, and together they let you predict what the unit will do in your room rather than hope.

The BTU figure is the one nobody else publishes and the one that actually lets you size a chiller properly. Horsepower is a compressor rating, not a cooling rating, and the relationship between the two varies by design. BTU per hour is the heat actually removed, which is the number that matters when you are deciding whether it can hold 132 gallons at 40 F in a warm garage.

At 1,030 W it is nineteen cents an hour at full draw - lower than both 1,200 W half-horse units here despite being a full horsepower, which is either better efficiency or a difference in how the figures were derived. The three-stage filtration is named by micron rating rather than described, and the ozone generator is a real sanitation method rather than a marketing word.