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Ton

A ton of heat pump capacity is 12,000 Btu per hour.

Editorial staffEdited by heatpumpwiki

History 1

A ton of capacity is 12,000 Btu per hour, about 3.5 kW. NIST lists the "ton of refrigeration (12 000 Btu_IT/h)" as 3,516.853 watts.Source 1 NRCan: a ton "is equivalent to 3.5 kW or 12 000 Btu/h."Source 2

Nominal tonnage is a label for comparison. Actual capacity changes with outdoor temperature, especially in heating. For sizing, the capacity at your design temperature matters more than the nominal ton. See Manual J, Manual S and Manual D explained and Btu (British thermal unit).

Sources

  1. 1.NIST Guide to the SI, Appendix B.9: Factors for units listed by kind of quantity or field of science. National Institute of Standards and Technology. Accessed Oct 25, 2026
  2. 2.Heating and cooling with a heat pump. Natural Resources Canada. Accessed Oct 25, 2026

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