Unitil time-of-use & off-peak hours

On GD-3, on-peak hours run 10 AM – 10 PM on weekdays. Below is every active TOU rate plan we track for Unitil — 2 plans — with period boundaries verified against the published tariff. No price values; periods only.

For developers & agents

Query Unitil 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 Unitil, with its period boundaries.

GD-3 Large General Delivery Service Commercial
PeriodSeasonDaysHours
On-Peak All year Mon–Fri 10 AM – 10 PM
Effective
Dec 1, 2024
Verified
EV-RES Residential Electric Vehicle Service EV
PeriodSeasonDaysHours
Mid-Peak All year Mon–Fri 6 AM – 3 PM
On-Peak All year Mon–Fri 3 PM – 8 PM
Effective
Dec 1, 2024
Verified

Frequently asked

  1. What are Unitil's on-peak hours?

    On the GD-3 plan (Large General Delivery Service), on-peak hours run from 10 AM – 10 PM on weekdays. All remaining hours are classified as off-peak.

  2. Does Unitil charge more for electricity at certain times?

    Yes. Unitil 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 2 active schedules; tou.tools does not publish pricing ($/kWh) details.

  3. How do I get Unitil 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 Unitil 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 Unitil's plans?

    For customers on EV-specific plans like EV-RES, 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.