Chiller Sizing Information

Plug in the following three inputs into the calculator below to get the estimated chiller size you need for your application.

  • The incoming water temperature
  • The chill water temperature you require
  • The flow rate



Chiller Size Calculator


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General sizing formula:

  1. Calculate Temperature Differential (?T°F) ?T°F = Incoming Water Temperature (°F) - Required Chill Water Temperature
  2. Calculate BTU/hr. BTU/hr. = Gallons per hr x 8.33 x ?T°F
  3. Calculate tons of cooling capacity Tons = BTU/hr. ÷ 12,000
  4. Oversize the chiller by 20% Ideal Size in Tons = Tons x 1.2
  5. You have the ideal size for your needs

For example, what size chiller is required to cool 40GPM from 70°F to 58°F?

  1. ?T°F = 70°F - 58°F = 12°F
  2. BTU/hr. = 40gpm x 60 x 8.33 x 12°F = 239,904 BTU/hr.
  3. Ton Capacity = 239,904 BTU/hr. ÷ 12,000 = 19.992 Tons
  4. Oversize the chiller = 19.992 x 1.2 = 23.9904
  5. A 23.9904 or 25-Ton chiller is required

There also industry specific rules of thumb for chiller sizing depending on your application:

Unsure what size chiller you need? Cold Shot Chillers is here to help. Contact us and we will work with you to determine the ideal sized chiller for your custom application.

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or call us at 1.800.473.9178