Thermostat settings by state
Thermostat settings in California
By Ismail Farooq · Updated 2026-10-30
How most homes heat: Gas furnaces in most homes, with fast growth in heat pumps; many coastal homes have little or no AC.
California has more climate zones than any other state, from the low desert to the Sierra. Coastal homes from San Diego to San Francisco need little cooling and gentle heating, while the Central Valley and inland Southern California are hot and dry in summer. Time-of-use electricity rates are the default for most customers of the big utilities, so the cheapest way to cool is to pre-cool before the late-afternoon and evening peak, then let the house drift up.
Smart thermostats can also earn money or bill credits through utility demand response programs, which nudge the setpoint up for a few hours on the hottest days. California also sets its own building energy code (Title 24), which uses its own 16 climate zones, so a contractor may quote a different zone number from the IECC zones shown here.
Climate zones in California
| Place | IECC zone |
|---|---|
| El Centro | 2B |
| Los Angeles | 3B |
| San Diego | 3B |
| San Francisco | 3C |
| Sacramento | 3B |
| Fresno | 3B |
| Eureka | 4C |
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.
- Marine (mild) areas: heat pumps rarely need aux heat, and many homes need little cooling.
- Freeze protection: keep the away or minimum temperature at about 55 °F or higher in winter, and make sure the thermostat keeps working without Wi-Fi.
Heat pump lockouts for California
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 |
| 6–8 | From the heat pump’s rated output at low temperatures; cold-climate models often run well below 10 °F | Often 0–25 °F, from the installer’s balance point |
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.