Cooling rate is how fast a chiller lowers water temperature, usually published in degrees Fahrenheit per hour. Manufacturers state it against a specific water volume and ambient temperature, and both matter: the same chiller cools 66 gallons far faster than 200, and works harder on a 90°F patio than in a 65°F garage.
Why it matters when you are comparing products
A cooling rate quoted without its water volume and ambient temperature is not comparable to anything. Check what conditions the figure assumes before treating it as a spec.
Where this comes up
- Cold plunges with chillers — Systems where the maker publishes a cooling rate.
Reviewed 2026-08-15