AC Tonnage Calculator

The AC Tonnage Calculator estimates recommended air conditioner size from room dimensions, ceiling height, occupants, room type, and sunlight exposure. Results are shown in tons of refrigeration (TR) and BTU per hour for HVAC sizing.

BTU to ton conversion

One ton of refrigeration equals 12,000 BTU per hour:

$$\mathrm{Tons} = \frac{\mathrm{BTU/hr}}{12{,}000}$$

Calculation methods

Quick estimate uses floor area, kitchen load, extra occupants, ceiling height above 8 ft, and sunlight adjustment. Manual J simplified uses:

$$\mathrm{BTU/hr} = \mathrm{Area} \times \mathrm{Height} + \mathrm{People} \times 100 + \mathrm{Windows} \times 1{,}000 + \mathrm{Doors} \times 1{,}000$$

Related tools: Air Conditioner BTU Calculator and BTU Calculator.

Frequently Asked Questions

How many BTU are in one ton of AC?

One ton of refrigeration equals 12,000 BTU per hour. Divide total BTU/hr by 12,000 to get tonnage.

Why does kitchen AC sizing need more capacity?

Kitchens generate extra heat from stoves, ovens, and refrigerators. The quick estimate method adds 4,000 BTU/hr for kitchen spaces.

What happens if AC tonnage is too low?

An undersized unit runs continuously, struggles to reach set temperature on hot days, and uses more energy while providing poor comfort.

What is Manual J calculation?

Manual J is an industry-standard residential HVAC load method that accounts for room volume, occupants, windows, and exterior doors to size cooling systems more accurately than area-only rules.

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AC Tonnage Calculator