A water chiller is a refrigeration unit that pumps water out of the plunge, cools it through a heat exchanger, and returns it. It replaces ice entirely, holding a set temperature continuously. Most units combine the compressor, a circulation pump and a filter in one chassis, and connect to the tub with two hoses.
Why it matters when you are comparing products
A chiller is the difference between a plunge you use daily and one you use when you remember to buy ice. It is usually the single most expensive component of a cold plunge setup.
Where this comes up
- Chillers — Standalone chillers with published capacity.
- What size cold-plunge chiller do you need? — Sizing one to your tub volume and climate.
Reviewed 2026-08-15