The default 801 kWh is the EIA Florida average for everything except AC: 13,990 kWh total minus 4,379 kWh AC per year, divided by 12. AC is priced on top of it, so TECO's higher rate above 1,000 kWh applies when your bill crosses it. Use your own bill if you know it. No fixed fees or taxes are included. [7]

Yearly AC kWh = tons × 12,000 Btu/h × 3,409 hours ÷ SEER2 ÷ 1,000. The 3,409 yearly full load hours and the SEER2 levels are the U.S. Department of Energy planning figures for hot-humid Southeast states. A 3 ton, 13.4 SEER2 unit comes to 9,159 kWh a year, matching DOE. We treat that as use at your starting setting. This is an estimate, not a reading from your home. [12]

The DOE hours sit on the heavy side. Florida measured and survey averages are lower: FSEC metered about 6,421 kWh a year of cooling in Central Florida homes, and EIA reports 4,379 kWh for Florida homes with AC. If your home runs lighter, pick "I know my yearly AC kWh" and enter your own number. [7, 14]

Summer month (model constant from a hot-humid Southeast climate; your climate may differ): Tampa averages 3,928 cooling degree days a year, and August has the most, 589 (NOAA 1991 to 2020 normals). We give August 589 ÷ 3,928 = 15.0% of yearly AC use. The average month is 1/12, or 8.3%. FSEC found about 90% of Florida cooling falls April to October, which fits. [13, 14]

We keep the prototype's linear setpoint model: F(T) = max(0.30, 1 + s × (78 − T)). Here s is 0.07 using TECO summer guidance, or 0.03 using the low end of FPL guidance. The 78°F reference and 0.30 floor are model choices inherited from the prototype, not measured physical limits. [6, 10]

Cooling kWh = (annual input ÷ 12) × F(chosen setting) ÷ F(starting setting). A schedule weights F by the hours at home, away and asleep, out of 24. Setbacks are limited to 86°F as a calculator boundary, not safety advice. Away hours take priority if the periods total more than 24. The notice above explains any adjustment.

We price AC as variable charges on (other use + AC use), minus variable charges on other use. One degree cooler compares the selected setting with that setting minus 1°F. Annual savings are average month savings × 12. Dollar results are rounded only for display. [1 to 5]

This is a simple illustration. It assumes an unchanged schedule each day. Monthly shares follow cooling degree days. It does not simulate weather, humidity, recovery time, equipment cycling or efficiency. Summer bills may be higher. FSEC field data also found about 7% more yearly cooling energy per degree, which supports the summer estimate. [14] No thermostat can guarantee these results.

ENERGY STAR reports about 8% average heating and cooling bill savings from certified smart thermostats based on field data. That is context, not an extra discount in this calculator or a prediction for your home. EPA cautions against treating the national average as a local savings value. [8]

Rates checked November 6, 2026 (EST). Size, climate and usage sources added November 7, 2026. Utility prices can change. References support the inputs and guidance, not a guarantee of this model.

1. EIA Electric Power Monthly, Table 5.3: U.S. average residential price 18.16¢/kWh, August 2026 (default rate)
2. Tampa Electric thermostat guidance, May 22, 2025: about 7% per degree in summer
3. EIA 2020 RECS, Table CE4.6.EL.ST: Florida homes average 13,990 kWh total and 4,379 kWh AC a year; released June 2023
4. ENERGY STAR smart thermostat FAQ: field data and approximately 8% average heating and cooling bill savings
5. DOE Energy Saver Guide 2022: schedules, setbacks and heat pump cautions
6. FPL summer guidance: 3% to 5% per degree between 75°F and 78°F
7. ENERGY STAR smart thermostat buying guidance: system types, stages and C-wire compatibility
8. U.S. DOE FEMP, residential central AC, hot-humid Southeast: 3,409 full load hours a year, 13.4, 15.2 SEER2 levels, 9,159 kWh for a 3 ton at 13.4 SEER2. The 14.3 SEER2 option is the 2023 Southeast minimum for split systems under 45,000 Btu/h. Home size ranges are our rule of thumb of about 600 sq ft per ton, not a load calculation.
9. Florida Climate Center, Tampa International Airport 1991 to 2020 normals (NOAA): 3,928 cooling degree days a year, 589 in August
10. FSEC-PF-369-02, metered Central Florida homes: 6,421 kWh yearly cooling, about 90% April to October, about 7% per degree