UniSource Energy Services time-of-use & off-peak hours

On ERRDTT, on-peak hours run 3 PM – 7 PM and 6 AM – 9 AM and 6 PM – 9 PM on weekdays. Below is every active TOU rate plan we track for UniSource Energy Services — 12 plans — with period boundaries verified against the published tariff. No price values; periods only.

For developers & agents

Query UniSource Energy Services periods programmatically.

One call returns the current period and the next transition time for any U.S. ZIP or address — GET /query/current over REST, or the same data through MCP for AI agents.

Get a free API key Read the docs

Rate plan schedules

Every active time-of-use plan we track for UniSource Energy Services, with its period boundaries.

ERRDTT Residential Demand Time-of-Use Tech (R-Tech) [pilot] Residential
PeriodSeasonDaysHours
On-Peak May 1 – Sep 30 Mon–Fri 3 PM – 7 PM
On-Peak Oct 1 – Apr 30 Mon–Fri 6 AM – 9 AM
On-Peak Oct 1 – Apr 30 Mon–Fri 6 PM – 9 PM
Effective
Feb 1, 2024
Verified
ERRESDT Residential Demand Time-of-Use Residential
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 3 PM – 7 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 PM – 9 PM
Effective
Feb 1, 2024
Verified
ERREST Residential Service Time-of-Use Residential
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 3 PM – 7 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGLGSST Large General Service Schools Time-of-Use Commercial
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 3 PM – 7 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGLGST Large General Service Time-of-Use Commercial
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 2 PM – 8 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGMGSST Medium General Service Schools Time-of-Use Commercial
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 3 PM – 7 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGMGST Medium General Service Time-of-Use Commercial
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 2 PM – 8 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGSGSDT Small General Service Demand Time-of-Use Commercial
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 2 PM – 8 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGSGST Small General Service Time-of-Use Commercial
PeriodSeasonDaysHours
On-Peak May 1 – Oct 31 Mon–Fri 2 PM – 8 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
EGDCFCX Stand-Alone Electric Vehicle Charging (DCFCX) EV
PeriodSeasonDaysHours
Super Off-Peak All year Every day 10 PM – 4 AM
On-Peak May 1 – Oct 31 Mon–Fri 2 PM – 8 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 5 PM – 9 PM
Effective
Feb 1, 2024
Verified
ERDSOTE Residential Demand Super Off-Peak Time-of-Use Electric Vehicle EV
PeriodSeasonDaysHours
Super Off-Peak All year Every day 10 PM – 5 AM
On-Peak May 1 – Oct 31 Mon–Fri 3 PM – 7 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 PM – 9 PM
Effective
Feb 1, 2024
Verified
ERSOTE Residential Super Off-Peak Time-of-Use Electric Vehicle EV
PeriodSeasonDaysHours
Super Off-Peak All year Every day 10 PM – 5 AM
On-Peak May 1 – Oct 31 Mon–Fri 3 PM – 7 PM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 AM – 9 AM
On-Peak Nov 1 – Apr 30 Mon–Fri 6 PM – 9 PM
Effective
Feb 1, 2024
Verified

Frequently asked

  1. What are UniSource Energy Services's on-peak hours?

    On the ERRDTT plan (Residential Demand Time-of-Use Tech (R-Tech) [pilot]), on-peak hours run from 3 PM – 7 PM and 6 AM – 9 AM and 6 PM – 9 PM on weekdays. All remaining hours are classified as off-peak.

  2. Does UniSource Energy Services charge more for electricity at certain times?

    Yes. UniSource Energy Services offers time-of-use (TOU) rate plans where electricity costs vary depending on the period. The period—peak, off-peak, mid-peak, or super off-peak—depends on the time, day, and season. This page lists boundaries for 12 active schedules; tou.tools does not publish pricing ($/kWh) details.

  3. How do I get UniSource Energy Services time-of-use periods in my app?

    Schedules are accessible programmatically via the tou.tools REST API and MCP server for AI agents. By querying a U.S. address or ZIP code, your application can instantly retrieve the current period and next scheduled transition time. Developer API keys are free.

  4. Do UniSource Energy Services time-of-use hours change during holidays or seasons?

    Yes. Peak hours and rate periods can vary by season (typically summer and winter halves) and special holidays. While some schedules like E-ELEC keep stable hours year-round, others introduce super off-peak windows or adjust peak times. Check each rate plan card above for specific seasonal boundaries.

  5. What is the best time to charge an EV under UniSource Energy Services's plans?

    For customers on EV-specific plans like EGDCFCX, ERDSOTE, ERSOTE, the most cost-effective time to charge is during super off-peak or off-peak hours. Charging during these designated windows significantly reduces electricity costs and minimizes demand on the grid.