How much cooling power (HP) do I need for a cold plunge?

It depends on tub volume, insulation and climate, not on price. A 1HP unit (roughly 8,000 to 12,000 BTU/hr) pulls a typical 100 to 160 gallon tub down in a reasonable time and holds it in most climates. A 1/2 to 3/4HP unit is fine for a small, well-insulated tub but will struggle with a big or uninsulated one, undersizing HP is the number one cause of "why is this so slow" complaints.

What does a chiller cost to run each month?

Once the water is cold, running cost is driven by how hard the compressor cycles, not by horsepower. A hot climate, an uninsulated tub or full sun make it cycle nearly continuously; an insulated tub in a mild climate barely runs. Stated draws range from about 600W to 2,900W, so use your unit's real wattage and your electricity rate to work it out, most owners land around $20 to $50 a month.

Do I need a chiller, or is ice cheaper?

Ice is far cheaper to buy and run, but you handle bags of ice each time. A chiller keeps the water cold and, on the filtered models, clean, so you can plunge on demand. For daily use a chiller earns its cost; for a couple of times a week, ice usually wins.

The best cold plunge chillers, matched to your tub and climate

By Craig Fearn, FRSPH·Updated July 2026·Independent, commission never changes our ranking

Some links below are affiliate links, they never change our ranking. Disclosure.

A matte-black cold plunge chiller unit beside a dark cold plunge tub with mist rising, on a slate patio at blue-hour twilight

A chiller is what turns a tub of water you fill with ice into a cold plunge you can use any morning without thinking about it. It is also the single biggest running cost on the cold side, and the spec people get wrong. The trick is simple: match cooling power (BTU per hour) to your tub's volume and your climate, not to the price tag. Here are the ones worth buying, and the sizing and running-cost logic the brands don't spell out.

The one thing to get right: size cooling to the tub, not the budget. Cooldown time scales with BTU/hr, not price. A 1HP unit (roughly 8,000 to 12,000 BTU/hr) cools a typical 100 to 160 gallon tub in reasonable time; drop to 1/2 or 3/4HP and a big or uninsulated tub takes three to four times longer, which is the number one complaint. Once cold, the monthly bill is set by how hard the compressor cycles, driven by your climate, tub insulation and sun exposure, not by horsepower. Work out your figure in the cost-to-run calculator.

The field, compared on cooling power

Chiller	Power	Cooling	Low temp	Tub size	Price
Plunge Chill 1HP Chiller	1 HP	8,000–10,000 BTU/hr	36°F	80–160 gal	$999
The Plunge — Evolve Standard Chiller	~0.5–0.8 HP (600W)	not stated	~39°F	not stated	$499
Nordik Premium 1HP Chiller	1 HP (2,900W)	high	37°F	~105 gal	~$2,500
Ice Barrel Chiller	1/2 HP	moderate	37°F	Ice Barrel 300/400/500, 3/4" fittings for others	$3,999
Penguin Chillers 3/4HP	3/4 HP	7,500 BTU/hr	39°F	150 gal	~$2,099
EcoPlus Commercial 1HP	1 HP	8,525 BTU/hr	not stated	up to 400 gal (tank rating)	~$1,100

Specs are maker-stated, July 2026. Where a figure is not published we say so rather than estimate. The target water temperature you're chilling to (most protocols use 50 to 59°F) matters more than shaving minutes off cooldown, we cover the evidence in the contrast therapy protocol. Confirm specs at the retailer, they change often.

Plunge Chill 1HP Chiller

Best value

$999

Cooling: 1 HP, 8,000–10,000 BTU/hr
Low temp: 36°F
Tub size: 80–160 gal
Filtration: 1-micron filter + 24/7 circulation

Buy it if the most cooling per dollar, with a real filter and a titanium heat exchanger, at less than half the price of the big names.

Watch out listed draw varies by SKU, confirm the amperage suits your circuit before you buy.

Buying link coming soon

The Plunge — Evolve Standard Chiller

Cheapest way to chill

$499

Cooling: ~0.5–0.8 HP (600W), not stated
Low temp: ~39°F
Tub size: not stated
Filtration: chiller only, no filtration

Buy it if the lowest entry price from the best-known plunge brand, if you already have a tub.

Watch out no filtration, so you manage water quality yourself, and it is slower to pull a big tub down.

Buying link coming soon

Nordik Premium 1HP Chiller

Best filtration

~$2,500

Cooling: 1 HP (2,900W), high
Low temp: 37°F
Tub size: ~105 gal
Filtration: 3-stage + ozone

Buy it if the cleanest water of the group, three-stage filtration plus ozone, matched to Nordik tubs.

Watch out a US price is not clearly published, and the ozone system is more to maintain.

Buying link coming soon

Ice Barrel Chiller

Best for Ice Barrel owners

$3,999

Cooling: 1/2 HP, moderate
Low temp: 37°F
Tub size: Ice Barrel 300/400/500, 3/4" fittings for others
Filtration: see listing

Buy it if a plug-and-play match if you already own an Ice Barrel, dedicated ports make install trivial.

Watch out the priciest here for only 1/2 HP, you pay for the brand fit, not the raw cooling power.

Buying link coming soon

Penguin Chillers 3/4HP

Proven workhorse

~$2,099

Cooling: 3/4 HP, 7,500 BTU/hr
Low temp: 39°F
Tub size: 150 gal
Filtration: micron filter + built-in pump

Buy it if a long-trusted unit with a built-in pump and filter, popular for DIY stock-tank builds.

Watch out no direct affiliate program, so we earn nothing from it, it is here on merit.

Sold through specialist cold-plunge retailers. We don't have an affiliate link for this one, so we earn nothing from it, it's here on the specs alone.

EcoPlus Commercial 1HP

Cheapest 1HP

~$1,100

Cooling: 1 HP, 8,525 BTU/hr
Low temp: not stated
Tub size: up to 400 gal (tank rating)
Filtration: chiller only

Buy it if the most raw cooling power for the money if you will add your own pump and filter.

Watch out it is a hydroponics chiller, not plunge-specific, so no filtration and a DIY plumbing job.

Sold on Amazon and hydroponics retailers. We don't have an affiliate link for this one, so we earn nothing from it, it's here on the specs alone.

Chiller plus your own tub, or an all-in-one?

A standalone chiller plus a stock tank or insulated tub is the cheapest route to always-cold water, and lets you size the cooling to your climate. But it is a plumbing job, and an uninsulated tub will run the chiller hard. If you would rather not build anything, an all-in-one cold plunge tub arrives with the chiller matched and the insulation sorted. And if you are still testing whether the habit sticks, start with a portable ice bath and add a chiller later. Pair the whole thing with heat in our sauna and cold plunge packages.

Common questions

How much HP do I need?

Match it to tub volume and climate, not price. 1HP (about 8,000 to 12,000 BTU/hr) suits a typical 100 to 160 gallon tub; smaller units struggle with big or uninsulated tubs.

Monthly running cost?

Driven by compressor cycling, not HP, so climate and insulation decide it. Most owners land around $20 to $50 a month. Calculate yours.

Chiller or ice?

Ice is cheaper but hands-on; a chiller gives cold on demand and, on filtered models, clean water. Daily use favours a chiller.

Sources & method

Horsepower, BTU/hr, temperatures, tub ratings and prices are taken from each brand's own product pages (Plunge Chill, Plunge, Nordik, Ice Barrel, Penguin Chillers, EcoPlus), current July 2026. Where a maker does not publish a figure, such as The Plunge's BTU rating or an uncertain wattage on some Plunge Chill SKUs, we mark it rather than guess. Cooling-to-tub sizing and running-cost drivers are general refrigeration facts cross-checked against multiple owner reports. Confirm specs and the electrical requirement with the retailer before buying.