Yes, a smart thermostat can run a heat pump, but only if it supports your equipment and the settings are right. Two settings matter most: the reversing valve wire (O/B) and the backup heat settings. Climate Pros Tucson matches you with licensed pros who can confirm both at your wall.

What is the O/B wire?

A heat pump flips between cooling and heating with a reversing valve. The thermostat signals it on a wire marked O or B. Brands differ on which one they energize in cooling. The thermostat setup has to match your equipment, and the installer should confirm it. A wrong choice can heat when you ask for cool.

What is aux heat?

Auxiliary heat is backup, usually electric strips or a gas furnace in a dual-fuel setup. It should kick in when the heat pump can’t keep up or during defrost. If it runs too often, power use climbs. Ask the pro how the thermostat decides when to use it.

Does that matter in Tucson?

Less than in colder places, but it still counts. The Tucson airport sees fewer than 12 freezing nights a year, and winter design temperature is 35F, so the heat pump handles most heating alone. In Summerhaven on Mount Lemmon, with about 53 nights a year at or below 32F, backup heat is a question for the pro. In the basin, a thermostat that leans on strips needlessly wastes power.

Which settings should you ask about?

  • Reversing valve (O or B) setting
  • Backup heat on or off, and when it can run
  • Defrost handling
  • Dual-fuel switchover, if you have gas
  • Compatibility with your exact equipment model

How do TEP time-of-use plans fit in?

TEP’s time-of-use plan has summer weekday on-peak from 3 to 7 p.m., May to September, and winter weekday on-peak from 6 to 9 a.m. and 6 to 9 p.m. A schedule helps you plan around those windows. See Nest vs Ecobee and the Nest 4th gen checklist.

Where to go next

Read about heat pump service, thermostat installation, and the Tucson HVAC hub. Also see heat pump vs AC.

Get the settings checked

Call (520) 353-2520 and we’ll match you with a licensed local pro. Share your heat pump’s make and model.