Cold Plunges with Chiller

Without a chiller, a cold plunge is an ice bath: you buy 100 pounds of ice for the first fill, top up daily, and drain and refill every week or two because standing water with no filter does not stay clean. A chiller replaces all of that. It is a small refrigeration unit with a pump; water circulates out of the tub, through a filter (and on most units an ozone or UV stage), across a cooling coil and back, and the controller holds whatever temperature you set, on a schedule if it has an app. The water stays usable for months with a filter change, and the cost moves from ice to electricity: a 1 HP chiller draws around 800 to 1,000 W while the compressor runs and cycles on and off, which in a garage works out to a few dollars a week, less in a cool room, more outdoors in summer.

Horsepower and gallons

Chiller size is rated in horsepower, and the right size depends on the water volume and where the tub lives:

• 1/3 HP: 50 to 80 gallons, indoors. The small inflatable-tub chillers.
• 1/2 HP: up to about 100 gallons indoors, or a smaller tub outdoors. The PlungeBox Half HP (39°F to 59°F) is in this class.
• 1 HP: 100 to 155 gallons, or outdoor use in a hot climate. The Icebound Pro chiller on the Endurance bundles (37°F to 107.6°F) is 1 HP on a 155-gallon tub.
• 1.5 HP and up: multi-user, commercial, or when you want the water back to temperature within an hour of use. The TheraFrost runs 1.75 HP.

More horsepower cools faster and holds in heat; it also costs more and draws more. A 1 HP unit on a 155-gallon tub is the sensible middle for a home.

The other specs

Lowest temperature (37°F to 40°F on the better units; some stop at 45°F); filtration (a cartridge filter at minimum, ozone or UV to keep bacteria down between changes); app control and scheduling, which lets the chiller pre-cool before your morning session and idle warmer in between; heating, on the Natural High and MedEq cold-and-hot systems, which turns the same tub into a warm soak; and noise and placement, since a compressor is about as loud as a window air conditioner and is best outside the room or on a rubber mat. Every chiller needs a GFCI outlet; the large pools may need their own circuit.

Tub-and-chiller bundles

• Icebound Essentials Pink Endurance Plunge Bundle, $1,699, Big Tex Endurance Bundle, $1,799, and Endurance Plunge Bundle, $2,099: the 155-gallon insulated Endurance tub pre-matched with the 1 HP Icebound Pro chiller, 37°F to 107.6°F, Wi-Fi scheduling, ozone and dual-stage filtration. The same three tubs in a different color and finish; the Endurance is the double-slipper.
• Modtub 2.0 Cold Plunge System, $2,495: the 90-gallon rotomolded Modtub with its chiller, the outdoor-permanent option. Being published to the store; it appears in the grid as soon as it is.

All-in-one systems

• Natural High Extreme Cold and Hot Plunge System, $2,489: insulated tub with a chiller-heater, 36°F to 107°F, ozone, app control. The lowest-priced unit here that also heats.
• Fire Cold Plunge All-In-One System, $3,695: integrated chiller and ozone in one cabinet.
• Therasage TheraFrost Cold Plunge System, $4,988: 1.75 HP chiller, ozone purification, app control; the most cooling power here.
• Icebound Essentials Resolute Pro All-In-One Cold Plunge, $4,999: 116-gallon hard-sided acrylic fixture with a Balboa spa controller, 40°F to 104°F, ozone. The one that looks like furniture.

Pools

• MedEq Acrylic Cold and Hot Plunge Pool With Massage Jets and Chiller, $6,250: cools, heats and jets.
• Natural High Premier Cold and Hot Plunge System, $6,490: acrylic, 35.6°F to 107°F, ozone, cold and hot.
• MedEq Stainless Steel Cold Plunge Pool With Integrated Chiller, $9,250: the commercial-grade stainless pool.
• MedEq Cold and Hot Plunge Pool With Integrated Chiller and Heater, $9,550: cold and hot in a wood-clad stainless pool.

Add-ons

• Therasage TheraFrost Flow, $987: pump, filtration and ozone for a tub you already own, with no chiller; the fix for water that will not stay clean.
• PlungeBox Half HP Water Chiller Pro, $1,799: 0.5 HP, 39°F to 59°F, for compatible tubs. Being published to the store.

Horsepower, gallons and temperature range are being confirmed for the Fire, Natural High, Modtub and MedEq systems and will fill the table as they arrive; the MedEq warranty terms are confirmed at quote.

• First chilled plunge, under $2,100: an Icebound Endurance bundle ($1,699 to $2,099): 155 gallons, 1 HP, 37°F, Wi-Fi, ozone, and the tub stands on its own if the chiller is ever away for service.
• Outdoors, year round: Modtub 2.0 System ($2,495), rotomolded, or the Icebound bundles under a cover.
• Cold and hot in one unit: Natural High Extreme ($2,489) is the entry; the Natural High Premier and the two MedEq cold-and-hot pools are the fixtures. All four are also on Contrast Therapy.
• The most cooling power: TheraFrost ($4,988) at 1.75 HP.
• A finished fixture for a home gym or spa room: Icebound Resolute Pro ($4,999) or the Natural High Premier ($6,490).
• Commercial, clinic or team room: the MedEq stainless and acrylic pools ($6,250 to $9,550), built for all-day use and more than one body a session; ask us about electrical and floor loading before ordering.
• Already own a tub: see the next section.

What to compare

Horsepower against your gallons and climate; the lowest temperature the unit will hold; filtration plus ozone or UV; app scheduling; whether it heats; the electrical requirement (standard GFCI outlet for the bundles and all-in-ones, a dedicated circuit for some pools); the floor load (155 gallons of water is about 1,300 pounds before the tub); and who handles the warranty. Chillers are the component that fails, so a unit sold by a brand with US support matters more here than on an ice-only tub.

If your tub has chiller ports (two bulkhead fittings, usually with 3/4-inch hose barbs), a chiller connects with two insulated hoses and runs from a GFCI outlet. The four Icebound tubs and the Modtub 2.0 Tub on Ice Bath Tubs have them and pair with the chillers in their bundles; the PlungeBox Half HP chiller ($1,799) is the standalone unit for PlungeBox and other compatible tubs, holding 39°F to 59°F. Inflatable tubs without ports are ice-only. If the water is the problem rather than the temperature, the TheraFrost Flow ($987) adds a pump, filter and ozone without cooling.

A DIY chiller build (an aquarium or hydroponic chiller, a separate pump, a filter housing, insulated hose, a GFCI) can come in under $1,000 and works if you are comfortable plumbing it and accept that no one warranties the assembly. A bundle is the same parts matched, insulated and covered by one warranty, which is what the price difference buys.

Buying from us

Every system is new, with the manufacturer warranty handled through us as your US point of contact (1 year on Icebound, Natural High, Fire, Therasage and Modtub; MedEq terms confirmed at quote). Freight is free to domestic USA addresses in the lower 48, curbside, on a pallet for the pools; Alaska, Hawaii and international by quote. 30-day returns on eligible products in original condition. Every cold tub we sell, chilled or not, is on Cold Plunge Tubs.