FixerCalc

HVAC Replacement Cost Calculator

Homeowners get quoted in tons and thousands of dollars. This calculator shows a coarse tonnage band from square footage and a cost range from editable $/ton—then tells you plainly it is not a load calculation.

Last reviewed 2026-08-25. How we calculate

Results update as you type. Units stay imperial inside the math.

House
System

Results

  • Rule-of-thumb capacity

    3.6 tons

    Not Manual J. Show this as a talking number only.

  • Tonnage band (400–600 sq ft/ton)

    3.0 – 4.5 tons

  • Installed cost range

    $16,200 – $30,600

  • System

    heatpump

Sq ft per ton used for midpoint
500
Conditioned area
1,800 sq ft
  • This is not Manual J, Manual S, or Manual D. Do not order equipment from this page.
  • Duct repairs, electrical upgrades, permits, and heat-pump vs. furnace design can dominate the price.

How this calculation works

  1. A mild climate uses 1 ton per 600 sq ft, mixed 500, harsh 400. We also show a band using 600 and 400 as bookends so you see uncertainty.
  2. Cost = suggested tons × your $/ton range + extras. Equipment only vs. full system replacement is a bid scope issue.
  3. Nothing here uses windows, insulation, or orientation. Those belong in Manual J.

tons_mid = sqft / sqftPerTon(climate); tons_low = sqft/600; tons_high = sqft/400; cost = tons_mid × $/ton + extras

What to do next

  • Hire a contractor who will perform (or show) a Manual J before you sign.
  • If someone sizes only from square footage and the existing unit’s tonnage, ask for the load calc anyway—old units were often wrong.
  • Ask whether ducts will be tested. A new condenser on leaky ducts wastes money.

FAQ

What is a ton?
12,000 BTU/h of cooling capacity. It is a unit of power, not the weight of the outdoor unit.
Can I use this to buy a 3-ton unit online?
No. Charge, airflow, line-set, and electrical have to match. Mismatched equipment is a comfort and warranty problem.

Sources

  • Rule of thumb only: about 1 ton per 400–600 sq ft depending on climate. Not ACCA Manual J
  • Default installed $/ton bands: typical US replacement planning ranges, 2026

Cost defaults are typical US planning bands, last reviewed 2026-08-25. Edit the price fields on this page rather than treating them as a local market index.