Thermostat settings by state
Thermostat settings in Arizona
By Ismail Farooq · Updated 2026-10-30
How most homes heat: Heat pumps and central AC with electric or gas heat in the desert; gas furnaces in the high country.
Arizona covers four climate zones. Phoenix and Tucson are cooling markets: summer highs are often well over 100 °F, AC runs day and night, and dry air means 78–80 °F indoors feels comfortable. Pre-cooling the house before the late-afternoon peak, then letting it drift up a few degrees, works well with a smart thermostat and suits time-of-use electricity plans common in the Phoenix area.
Flagstaff and the high country are a different climate, with cold, snowy winters where a gas furnace and normal setbacks make sense. In the desert, an AC that can’t keep up in July is usually an equipment problem, not a thermostat one; check filters and the outdoor unit before blaming the settings.
Climate zones in Arizona
| Place | IECC zone |
|---|---|
| Phoenix | 2B |
| Tucson | 2B |
| Kingman | 3B |
| Prescott | 4B |
| Flagstaff | 5B |
Zones follow county lines on the 2021 IECC map, and some counties changed zone between code editions. DOE’s Building America climate zone map lists every county.
Starting settings
- Everyday setpoints: about 68 °F in winter and 78 °F in summer while you’re home, set back while you sleep or are out (DOE’s guidance).
- Gas, oil or propane furnace or boiler: setbacks of 7 to 10 °F are fine; use the thermostat’s early-start feature so the house is warm on time.
- Heat pump: keep winter setbacks small (2 to 4 °F) so a cold morning doesn’t bring on aux heat.
- Dry air: a higher cooling setpoint still feels comfortable, and winter air gets very dry. A whole-house humidifier wired to the thermostat should aim for about 30–40%, lower in very cold weather.
Heat pump lockouts for Arizona
If you have a heat pump, these are starting points for the outdoor temperatures that control backup heat. Your installer’s balance point is better if you have it.
| Zone | Aux heat lockout (electric strips) | Compressor lockout (dual fuel) |
|---|---|---|
| 1–2 | About 40 °F. Aux heat should almost never be needed. | Rarely needed |
| 3 | 35–40 °F | Around 25–35 °F, by gas vs electricity price |
| 4 | 30–35 °F | Around 25–35 °F |
| 5 | 25–35 °F for a standard heat pump; lower for a cold-climate model | Around 20–35 °F |
Rebates
Many utilities give rebates or bill credits for smart thermostats, sometimes in return for joining a peak-day program. Programs change often, so check your electric and gas utility’s website, or search by ZIP code in the ENERGY STAR rebate finder.