Would switching to a TOU plan save you money? Enter your monthly usage, your current flat rate, the TOU plan's peak / mid / off-peak rates, and what percentage of your usage falls in each band. The calculator stacks them honestly - including when TOU costs more than flat.
A TOU plan typically defines three rate bands by time of day and season: peak (weekday afternoons / early evenings in summer, the most expensive band), mid-peak (shoulder hours, moderate), and off-peak (overnight, weekends, the cheapest band). The exact hour boundaries vary by utility - PG&E's E-TOU-C runs peak 4-9pm summer weekdays; ConEd's SC1-VRT2 splits differently; ERCOT retailers offer free-nights products that are effectively two-band TOU.
The point of the rate gap is to encourage shifting load. A heat pump pre-cooling your home from noon to 3pm so the compressor doesn't run from 4-9pm is straight TOU economics. EV charging set to start at 9pm or midnight is the same. Solar households with batteries can run the house from battery during peak and recharge overnight, which is the strongest TOU win pattern.
A household with central AC running 4-9pm in summer, on a 4pm-9pm peak window, often pays more on TOU than on flat-rate. The calculator surfaces this directly - if your peak percentage is high, the saving line goes negative and the alert turns red. Do not enrol in TOU based on marketing - run your actual load profile through the calculator first.
Updated 2026-05-11