Manual-J-Lite Planning Tool
AC Size / BTU Calculator
Use this tool before an AC replacement estimate to understand the likely BTU and tonnage range. Florida humidity, duct leakage, west-facing glass, attic heat, additions, and return airflow can all change the final answer.
Last updated June 5, 2026Reviewed by Climate Control Services team
Quick answer
What size AC do I need for my Florida home?
A quick Florida planning estimate starts around 20 BTU per square foot, then adjusts for ceiling height, insulation, sun exposure, and extra occupants. The right installed size still needs a load calculation and duct review before replacement.
How This Calculator Works
Estimated BTU = square footage x 20 x ceiling-height factor x insulation/sun/occupancy adjustments. Estimated tons = BTU divided by 12,000, rounded to the next common half-ton planning size.
Florida Factors to Review
Palm Beach County homes often need sizing decisions to account for humidity removal, attic heat, coastal exposure, additions, duct leakage, and whether the current system ever cooled evenly.
Calculator FAQs
Is 20 BTU per square foot enough for Florida?
It is only a planning baseline. Florida homes can move above or below that number depending on insulation, windows, ceiling height, shade, duct condition, humidity load, and room layout.
Can I replace my AC with the same tonnage?
Sometimes, but the old tonnage should not decide the replacement by itself. The home may have changed, or the old system may have been oversized, undersized, or limited by ducts.
Why can an oversized AC be a problem in Florida?
An oversized AC can satisfy the thermostat quickly without enough runtime to remove moisture, which can leave the home sticky, uneven, and short cycling.
Estimate Disclaimer
Calculator results are planning estimates for homeowner education. They are not a Manual J load calculation, diagnostic finding, utility bill audit, financing approval, rebate confirmation, or installed-price quote. Climate Control Services can inspect the home, review equipment, and explain written options before work begins.