AC running cost in Phoenix, AZ: SRP vs APS
Phoenix averages 4,765 cooling degree days a year at Phoenix Sky Harbor Intl Airport, about 1.6× Arizona's statewide average. A typical 2,000 sq ft home's central AC uses roughly 5,391 kWh a year (estimate; see method).
Phoenix climate (NOAA 1991–2020 normals, Phoenix Sky Harbor Intl Airport)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2 | 16 | 105 | 259 | 528 | 792 | 945 | 910 | 727 | 390 | 88 | 2 |
Cooling degree days, base 65°F. Source: NOAA NCEI Monthly Normals, station USW00023183
SRP (Salt River Project): Basic Price Plan (E-23), not time-of-use
Estimated AC energy cost for a 2,000 sq ft Phoenix home (average insulation, 14 SEER2): $666/year, peaking at $145 in Jul.
| Month | Energy price | AC kWh | AC cost |
|---|---|---|---|
| Jan | 10.97¢ | 2 | $0 |
| Feb | 10.97¢ | 18 | $2 |
| Mar | 10.97¢ | 119 | $13 |
| Apr | 10.97¢ | 293 | $32 |
| May | 11.66¢ | 597 | $70 |
| Jun | 11.66¢ | 896 | $104 |
| Jul | 13.60¢ | 1,070 | $145 |
| Aug | 13.60¢ | 1,029 | $140 |
| Sep | 11.66¢ | 823 | $96 |
| Oct | 11.66¢ | 441 | $51 |
| Nov | 10.97¢ | 100 | $11 |
| Dec | 10.97¢ | 2 | $0 |
Prices: winter (Nov–Apr) 10.97¢, summer (May/Jun/Sep/Oct) 12.04¢, summer peak (Jul–Aug) 13.98¢/kWh, minus SRP's temporary $0.0038/kWh reduction for May–Oct 2026 billing cycles. Excludes monthly service charge, taxes and fees. Sources: www.srpnet.com · www.srpnet.com
Time-of-use option (Conserve 6-9 p.m. and Save): Jul–Aug on-peak 40.20¢, off-peak 12.76¢, super off-peak 6.61¢/kWh. Pre-cooling before the peak window is the main lever. Source: SRP plan comparison
APS (Arizona Public Service): Time-of-Use 4pm-7pm Weekdays (R-TOU-E)
On-peak is 4-7 p.m. Monday-Friday (excluding listed holidays). Your AC cost depends on how much of its running happens on-peak. Adjust the share below (25% is a placeholder assumption, not measured data).
Summer (May–Oct bills): on-peak 34.396¢, off-peak 12.345¢. Winter: on-peak 32.543¢, off-peak 12.351¢, super off-peak (10am–3pm weekdays) 3.495¢/kWh. Basic service charge $0.458/day (not included: doesn't change with AC use). Excludes adjustors, taxes and fees (per APS). Tariff effective March 8, 2024 (Decision No. 79293), tariff sheet retrieved Oct 2026. Sources: APS tariff · APS plan page