SRP E-27 Peak Hours: Summer and Winter Schedule
These primary sources support the schedule and rate claims in this guide.
Summer on-peak
2-8pm weekdays
May 1–October 31, excluding E-27 holidays
Winter on-peak
5-9am & 5-9pm
November 1–April 30 weekdays; not 2-8pm year-round
Demand basis
Max 30-min kW
Highest on-peak interval in the billing cycle, tiered
On SRP's E-27 Customer Generation Price Plan, peak hours are not 2pm–8pm every day of the year. Summer weekdays use a 2pm–8pm on-peak window. Winter weekdays use morning and evening windows instead. Demand is progressive, not a single flat dollars-per-kW number.
This page was rebuilt from SRP's E-27 tariff in the 2025/2026 ratebook (published 2026-04-27), including the temporary May–October 2026 fuel and purchased-power adjustment already reflected in the site constants. It covers E-27 only. Other SRP residential plans use different peak windows. Confirm the plan name on your bill before copying this schedule.
Who this schedule applies to
E-27 is limited to residential customers with on-site generation who do not buy all of their energy from SRP. It is currently marketed as the Customer Generation Price Plan. The ratebook states the plan will be eliminated as of the November 2029 billing cycle, with remaining customers moved to E-16. Non-generation SRP plans are outside this page.
Current E-27 on-peak and off-peak windows
| Calendar period | On-peak (MST) | Off-peak |
|---|---|---|
| May 1 – October 31 | 2 p.m. – 8 p.m. Monday–Friday, excluding holidays | All other hours, weekends, and holidays |
| November 1 – April 30 | 5 a.m. – 9 a.m. and 5 p.m. – 9 p.m. Monday–Friday, excluding holidays | All other hours, weekends, and holidays |
Times are Mountain Standard Time as written in the tariff. Weekends are off-peak all day on E-27. Christmas Eve and the day after Thanksgiving are not on the E-27 holiday list, so a weekday Christmas Eve or Black Friday still uses the normal on-peak windows.
E-27 off-peak holidays in 2026
The tariff names six holidays: New Year's Day (observed), Memorial Day, Independence Day (observed), Labor Day, Thanksgiving Day, and Christmas Day (observed). Those days are off-peak all day.
| Holiday | 2026 date | E-27 treatment |
|---|---|---|
| New Year’s Day (observed) | Thu, Jan 1 | Off-peak all day |
| Memorial Day | Mon, May 25 | Off-peak all day |
| Independence Day (observed) | Jul 4 is Sat in 2026 | Off-peak all day on the observed weekday SRP applies |
| Labor Day | Mon, Sep 7 | Off-peak all day |
| Thanksgiving Day | Thu, Nov 26 | Off-peak all day |
| Christmas Day (observed) | Fri, Dec 25 | Off-peak all day |
July 4 falls on Saturday in 2026. The E-27 tariff names Independence Day as observed but does not spell out the weekend observation rule in the ratebook text reviewed for this page. U.S. utility practice commonly observes a Saturday Independence Day on the preceding Friday (July 3 in 2026); Saturday is already off-peak because it is a weekend. Confirm the observed weekday on your SRP materials or bill if you need certainty for a specific date.
Three billing seasons for prices
Peak hours follow the May–October and November–April windows above. Energy and demand prices use three billing-cycle seasons from the ratebook:
- Summer: May, June, September, and October billing cycles
- Summer Peak: July and August billing cycles
- Winter: November through April billing cycles
| Billing season | On-peak energy | Off-peak energy | Demand tiers ($/kW) |
|---|---|---|---|
| Summer | 6.24¢/kWh | 5.22¢/kWh | $9.77 / $16.24 / $29.18 |
| Summer Peak (Jul–Aug) | 7.85¢/kWh | 5.75¢/kWh | $11.90 / $19.97 / $36.05 |
| Winter | 6.73¢/kWh | 6.34¢/kWh | $4.93 / $7.02 / $11.00 |
Demand tiers are first 3 kW, next 7 kW, and all additional kW. Service charges are $20, $30, or $40 depending on dwelling type and service amperage. These are tariff core charges before taxes and other riders. Model the base math with the SRP E-27 bill calculator.
Why progressive demand matters more than the energy spread
In July–August, moving one kWh from on-peak to off-peak changes the base energy charge by about 2.10¢. In winter, the energy spread is only about 0.39¢ per kWh. The larger E-27 lever is usually the on-peak demand charge.
Example only: an 8 kW maximum thirty-minute on-peak demand in a July–August billing cycle prices as 3 kW × $11.90 plus 5 kW × $19.97, or about $135.55 for that cycle's demand charge alone. It is not 8 × a single flat $/kW rate. Your meter and bill decide the actual demand.
- Avoid stacking AC, pool pumps, dryers, ovens, and Level 2 EV charging inside the same on-peak half-hour.
- In summer, finish major flexible loads before 2pm or start them after 8pm on weekdays.
- In winter, watch both the morning 5–9am window and the evening 5–9pm window—not only late afternoon.
- Use the pool pump calculator and EV charging calculator for equipment-level timing estimates.
- For solar self-use versus export timing on E-27, remember exports are netted by matching time-of-use period, not one flat export rate.
Do not mix E-27 with other SRP peak schedules
Other SRP residential plans use different clocks. For example, some demand and TOU plans use evening-centered windows rather than E-27's summer 2–8pm block and winter split windows. APS TOU-E is also different: a 4–7pm weekday peak with a winter super-off-peak band—see the APS off-peak hours guide. The plan printed on your bill is the authority.
SRP publishes current plan materials on its price plans section. If a consumer page and the ratebook ever disagree, use the ratebook and your bill.
Frequently asked questions
What are SRP E-27 peak hours in summer?
From May 1 through October 31, on-peak hours are 2 p.m. to 8 p.m. Mountain Standard Time, Monday through Friday, excluding the six tariff holidays. All other hours are off-peak.
What are SRP E-27 peak hours in winter?
From November 1 through April 30, on-peak hours are 5 a.m. to 9 a.m. and 5 p.m. to 9 p.m. Mountain Standard Time, Monday through Friday, excluding the same holidays. The summer 2–8pm window does not apply in winter on E-27.
Does E-27 use one flat demand charge?
No. Billing demand is the maximum thirty-minute integrated kilowatt reading during on-peak periods in the billing cycle. That demand is priced in progressive tiers for the first 3 kW, the next 7 kW, and all additional kW, with different tier prices by billing season.
Source notes
- SRP ratebook with temporary FPPAM (E-27 section) — on-peak definitions, holidays, seasons, energy prices, progressive demand tiers, service-charge tiers, demand interval, export netting, and November 2029 elimination note. Published 2026-04-27.
- Site constants in
SRP_RATES— verified 2026-07-27 against that ratebook for calculator use. - SRP price plans hub — consumer-facing plan navigation; not a substitute for the tariff text.
Source set reviewed 2026-07-27. Rates, temporary adjustments, and plan availability can change. The linked SRP ratebook and your own bill take priority over this summary. Results on the companion calculator are estimates of core E-27 charges, not a complete bill.