HomeWattCost

SRP E-23 vs E-28

E-23 and E-28 cost about the same for a typical Arizona home (within $2 a year). They stay within about 1% of each other at every level of use from 200 to 2,500 kWh a month, with the same daily pattern of use.

Utility SRPTariffs checked 2026-10-29Typical use 1,054 kWh/mo, Arizona

Head to head

ScenarioE-23E-28Cheaper
Typical home, per month$159$158Tie
All-in price per kWh15.0¢15.0¢Tie
Home + EV, charged at the cheapest hour$191$171E-28
Home + EV, plugged in at 6 pm$191$210E-23
Fixed charge$30.00$30.00

Typical home: Arizona average use by month (EIA), shaped hour by hour (NREL ResStock), before taxes. EV: Tesla Model Y Long Range AWD, 1,000 miles a month; cheapest start any hour on E-23, 8 am on E-28.

Month by month

Typical-home bill each month on each plan.

PlanJanFebMarAprMayJunJulAugSepOctNovDec
E-23$113$100$124$120$157$204$269$280$187$134$106$109
E-28$111$99$124$119$157$204$272$283$186$134$105$107

E-23: price by hour

July weekday.

Same price all day
14.0¢12a3a6a9a12p3p6p9p12a

E-28: price by hour

July weekday.

Off-peakMid-peakPeak
12.8¢6.6¢12.8¢40.2¢12.8¢12a3a6a9a12p3p6p9p12a

E-23 or E-28: common questions

Is E-23 or E-28 cheaper?

E-23 and E-28 cost about the same for a typical Arizona home (within $2 a year). They stay within about 1% of each other at every level of use from 200 to 2,500 kWh a month, with the same daily pattern of use. Adding an EV driven 1,000 miles a month and charged at each plan’s cheapest hour, E-28 gives the lower total ($171 against $191 a month).

What is the difference between E-23 and E-28?

E-23 is flat: the same price at every hour, with a fixed charge of $30.00 a month. E-28 is time-of-use (summer weekdays: Mid-peak 12 am–8 am, Mid-peak 3 pm–6 pm, Peak 6 pm–9 pm, Mid-peak 9 pm–12 am; lowest price 8 am–3 pm), with a fixed charge of $30.00 a month.

How the two plans work

E-23: Basic Price Plan

  • One price per kWh at every hour: 14.0¢ in July and 11.0¢ in January.
  • Shifting use to other hours changes nothing on this plan; using less is the only lever.
  • Fixed charge: $30.00 a month.

E-28: Conserve 6-9 p.m. and Save

  • Mid-peak 12 am–8 am, Mid-peak 3 pm–6 pm, Peak 6 pm–9 pm, Mid-peak 9 pm–12 am on July weekdays; 3 of 24 hours carry the top price of 40.2¢.
  • The cheapest July weekday hour costs 6.6¢, so moving 1 kWh out of the top hours saves 33.6¢.
  • January weekdays range from 4.3¢ to 15.1¢.
  • Weekends differ: Mid-peak 12 am–8 am, Mid-peak 3 pm–12 am.
  • Fixed charge: $30.00 a month.

Your own pattern of use decides the winner: compare every SRP plan on your usage, or see all SRP plans, sources and peak hours.