Free HVAC sizing tool

Manual J Sizing Calculator

Tell us about your home — square footage, ceilings, insulation, ducts, windows — and we'll estimate the cooling load (sensible + latent) plus the recommended residential tonnage. Tuned for climate zone 2A / Southeast Louisiana.

Sizing inputs
Tell us about your home

Total area of all cooled/heated spaces.

8 / 9 / 10 ft are most common in SE Louisiana.

4

Count only the south/west-facing windows that take afternoon sun.

3

People routinely home during the day add latent load.

Your result
4-ton 15-16 SEER two-stage heat pump
Total
43,609
BTU/hr cooling
System
4 tons
12,000 BTU/hr per ton
Sensible
29,654
BTU/hr (temperature)
Latent
13,955
BTU/hr (humidity)
How we got there
  • Base load23,400 BTU/hr
  • Ceiling (9 ft)× 1.10
  • Insulation (average)× 1.15
  • Duct location (attic)× 1.22
  • Sun-facing windows (4)+2,000 BTU/hr
  • Occupants (3)+1,200 BTU/hr latent
  • Envelope tightness× 1.10

Download a printable PDF with the full breakdown and your contact info.

Want a real Manual J audit?

This calculator is a homeowner approximation. A 30-minute on-site visit confirms the numbers against actual window orientation, duct runs, and shading before equipment is ordered.

Call (225) 555-0100 — Emergency