ACCA Manual J (Whole House)

What Size Air Conditioner for 1,500 Square Feet?

A 1,500 sq ft house lands near 2.5 tons, but climate moves it a lot. Here is the range, the typical size, and the calculator to nail it down.

Quick answer: A 1,500 sq ft house needs roughly 2.5 tons (~30,000 BTU) in a moderate climate, from 21,000 BTU (cold) to 37,500 BTU (hot). Size it with a Manual J load calculation, not floor area alone.

The Numbers for 1,500 Sq Ft

Cooling capacity (typical, moderate climate)30,000 BTU/hr
Tonnage~2.5 ton
Range by climate (cold to hot)21,000 - 37,500 BTU
Typical equipmenta 2.5-3 ton central air conditioner

Whole-house figures use ~14 BTU/sq ft (cold climate) to ~25 (hot humid), ~20 typical. The accurate number comes from an ACCA Manual J calculation; use the calculator below.


Estimate Your Exact Load

Enter your climate zone, insulation, windows, and duct location for a Manual-J-style estimate and tonnage.

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Frequently Asked Questions

What size AC does a 1,500 square foot house need?

Roughly 2.5 tons (about 30,000 BTU) in a moderate climate. The real range runs from about 21,000 BTU (1.8 tons) in a cold climate to about 37,500 BTU (3.1 tons) in a hot, humid one. A whole-house load depends on climate, insulation, windows, and ceiling height, so it is sized with an ACCA Manual J calculation, not floor area alone. Typical equipment: a 2.5-3 ton central air conditioner.

How many BTU for a 1,500 sq ft house?

Plan on about 18-20 BTU per square foot in a moderate climate, which is roughly 30,000 BTU for 1,500 sq ft. Hot climates push toward 22-25 BTU/sq ft and cold climates drop to 12-16, so the same house can need anywhere from 21,000 to 37,500 BTU depending on where it is.

Can I size a whole house by square feet alone?

Only as a ballpark. Square footage gives a starting tonnage, but two 1,500 sq ft houses in different climates, or with different insulation and window areas, can need a full ton apart. For equipment you are going to buy and install, run a Manual J load calculation. Oversizing short-cycles the system and leaves the house humid; undersizing cannot keep up on design days.


Other Sizes