Last updated: October 3, 2026
AC and heat pump size calculator for Tucson homes
Enter your square footage, pick your part of the Tucson area and set the home profile. You get a cooling load estimate in BTU per hour and a tonnage range to compare against a contractor's quote. It's a rule of thumb, not the load calculation the City of Tucson requires.
Want the real load calculation? Call (520) 353-2520. Climate Pros Tucson matches you with a licensed local pro who runs the load and sizing calculations the City of Tucson requires before quoting.
Call (520) 353-2520How this works. The baseline BTU per square foot is a rule of thumb scaled to the code summer design temperature for your area (City of Tucson 105F; Pima County 107F west of the Tohono O'odham Reservation's eastern boundary; 90F above 4,000 feet). Home age and ceiling height apply estimator multipliers. The result is a check on a quote, not a bid, and Climate Pros Tucson publishes no installed prices. For rebates, TEP's Efficient Home Program lists current amounts for participating contractors.
FAQ
Is this a real load calculation?
No. A full load calculation (ACCA Manual J) accounts for window orientation, shading, insulation, air leakage and duct losses room by room. The City of Tucson requires load and sizing calculations for new and replacement HVAC equipment, so the licensed contractor runs one before quoting. This tool gives you a number to compare against that quote.
Why does the calculator use 105F for Tucson?
That is the City of Tucson's summer design dry bulb temperature under its 2024 energy code amendments, with 35F for winter. Pima County uses 107F west of the Tohono O'odham Reservation's eastern boundary and 90F above 4,000 feet. Design temperatures are what code-compliant sizing uses, not the record high.
Does this work for heat pumps?
Yes, in the Tucson basin. The airport averages about 2.6 cooling degree days for every heating degree day (1991-2020 normals), so a heat pump sized for cooling normally has heating to spare at the 35F design temperature. On Mount Lemmon and in Summerhaven, heating drives the choice; ask the pro for a heating load there.
Does it work for a rooftop package unit?
The load is the same whether the equipment is a split system or a package unit on the roof. The pro picks the equipment that matches the load and fits the roof or pad.
What about two-story homes?
The calculator assumes one story or a uniform two-story layout. If the upstairs runs hotter, a zoned system or a mini split for the upper floor needs its own load calculation per zone.
Next: compare a heat pump with AC and a gas furnace, read what size AC a Tucson home needs, or see AC installation across the Tucson area.
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