Ton (HVAC Capacity)

In HVAC, “ton” doesn’t refer to weight — it’s a unit of cooling capacity equal to 12,000 BTU per hour. The name is a holdover from the days of using ice for refrigeration: one ton = the cooling provided by melting one ton of ice over 24 hours.

Residential AC sizes

Central AC units come in half-ton increments:

• 1.5 ton = 18,000 BTU/hr
• 2 ton = 24,000 BTU/hr
• 2.5 ton = 30,000 BTU/hr
• 3 ton = 36,000 BTU/hr
• 3.5 ton = 42,000 BTU/hr
• 4 ton = 48,000 BTU/hr
• 5 ton = 60,000 BTU/hr

Most Colorado homes between 1,500-3,000 sq ft fall in the 2-3 ton range. Mountain homes and larger footprints typically need 3.5-5 tons. Don’t guess — a Manual J load calculation is the only correct way to size.

Related: BTU, Manual J.