Key facts
- Horsepower labels are not standard. Penguin's two 1/2 HP units are rated 5,000 and 5,750 BTU per hour (maker spec pages, checked Oct 23, 2026).
- Penguin's packaged plunges hold 83 to 96 gallons and ship with a 7,500 BTU per hour chiller drawing 450 watts on 110 to 120V.
- 1 HP class units in our catalog are rated 11,500 to 15,000 BTU per hour and draw 830 to 1,270 watts.
- Climate, sun, lid use and how many people plunge per day change the heat load more than tub shape does.
Published chiller specs
| Chiller | Cooling | Power | Current | Voltage | Price at maker |
|---|---|---|---|---|---|
| Penguin Chillers 1/2 HP Water Chiller | 5,000 BTU/hr | 450W | 3.9A | 100-120V | From $1,000 |
| Penguin Chillers 1/2 HP High Efficiency (HE) Water Chiller | 5,750 BTU/hr | 450W | 3.9A | 110-120V | From $1,100 |
| The Cold Life Pro Curve Chiller | 3/4HP, 7500 BTU | 110V, 450W, 4AMP Power Cord 10' Power Cord w/ GFCI Hose | Not listed | Not listed | From $3,799 |
| Penguin Chillers 1 HP High Efficiency (HE) Water Chiller | 11,500 BTU/hr | 830W | 7.2A | 110-120V | From $2,000 |
| Penguin Chillers 1 ½ HP Water Chiller | 15,000 BTU/hr | 1270W | 11A | 110-120V | From $2,600 |
| Penguin Chillers 2 ½ HP Water Chiller | 25,000 BTU/hr | 3200W | 14.7A | 208-240V | From $3,600 |
A simple sizing rule
| Your setup | Start with |
|---|---|
| 80 to 100 gal, indoors or shaded, 1 to 2 users, lid on, 45 to 50 F target | 1/2 HP class, about 5,000 to 5,750 BTU/hr |
| 80 to 100 gal outdoors with summer heat, or a 37 to 40 F target | 3/4 HP class, about 7,500 BTU/hr |
| 120 gal or more, hot sun, desert climate, or several users a day | 1 HP class, 11,500 BTU/hr or more |
This table is our editorial starting point built from the maker pairings above, not a maker rule. When you are between two sizes, size up: an oversized chiller simply cycles off sooner, while an undersized one runs all day and may never reach your set point.
Worked example
A 95 gallon plunge in a Seattle garage, used once a day with the lid on, is the easy case: a 1/2 HP HE unit at 5,750 BTU per hour has room to spare. Move the same tub to a sunny Henderson patio in July and the heat load climbs sharply, so a 1 HP HE unit at 11,500 BTU per hour, in shade, is the safer choice. At 830 watts, each running hour uses about 0.83 kWh.
Placement and power
- Give the chiller the air clearance the manual lists so it can reject heat. See chiller noise and placement.
- Use a GFCI protected receptacle on a circuit that is not shared with other big loads. See GFCI and electrical requirements.
- Estimate running cost with our chiller power and cost guide.
Related guides
- Cold plunge chillers in Las Vegas heat
- Cold plunges through a Pacific Northwest winter
- The best cold plunges of 2026
- Renu Therapy cold plunges compared
- The Cold Life plunges compared
Frequently asked questions
What size chiller do I need for a cold plunge?
For a typical 80 to 100 gallon home plunge used by one or two people, indoors or in shade, a 1/2 HP class chiller rated around 5,000 to 5,750 BTU per hour is the usual starting point. Size up to a 1 HP class unit, 11,500 BTU per hour or more, for hot climates, sun, larger tubs or back-to-back users.
Is 1/2 HP enough for a cold plunge?
Often, yes. Penguin Chillers rates its 1/2 HP HE unit at 5,750 BTU per hour on 450 watts, and the same company pairs a 7,500 BTU per hour chiller with its 83 to 96 gallon plunges. A 1/2 HP unit struggles most in hot sun, a garage that bakes, or when the lid stays off.
Why compare BTU instead of horsepower?
Horsepower describes the compressor, not how much heat leaves the water, and labels are not standardized. Two 1/2 HP units in the Penguin line are rated 5,000 and 5,750 BTU per hour. The Cold Life calls its 7,500 BTU per hour chiller 3/4 HP. Compare published BTU per hour and watts.
Does a 1 HP chiller need 240V?
Not always. Penguin lists its 1 HP HE unit at 110 to 120V, 7.2 amps and 830 watts, and its standard 1 HP at 110 to 120V and 11 amps. Its 2 HP unit moves to 208 to 240V and 14.7 amps. Check the manual, and use a GFCI protected dedicated circuit either way.
How much power does a cold plunge chiller use?
The 1/2 HP units in our catalog draw about 450 watts while the compressor runs, so roughly 0.45 kWh per running hour. The 1 HP HE draws 830 watts. Your monthly cost depends on how many hours it runs, which depends on climate, lid use and set point. See our chiller running cost guide for the formula.
Can a chiller keep up in Las Vegas summer heat?
It can, with margin and shade. Hot air reduces how well any chiller sheds heat, and some units list maximum operating air temperatures near 100 F. In desert climates, size up a class, keep the chiller shaded and ventilated, and keep an insulated lid on. See our Las Vegas chiller guide.
Keep reading
Browse our cold plunges collection, see all guides, or ask us a question about your project.