A time of use rate charges different prices for electricity in different hours of the day. Instead of one flat price for every kilowatt hour, the day is cut into windows, usually a peak window in the late afternoon and evening, an off-peak window overnight, and sometimes a middle tier between them, each with its own fixed price. The windows and prices are published in advance and stay put for a season or a year, so you always know what an hour will cost before it arrives.
The pitch is simple: shift what you can into the cheap hours and you pay less. Whether that actually happens for a given home is not decided by the rate. It is decided by the home's usage shape, and that is the part this page is honest about.
How a time of use plan works
Every time of use plan is three published facts: the window boundaries, the price in each window, and the season they apply to. A typical structure prices the peak window, often mid afternoon to early evening on weekdays, several times higher than overnight hours. Weekends and holidays are usually all off-peak. Your meter records when you use power, your usage in each window is added up, and each window's total is billed at that window's price. There is no guessing and no market movement; the schedule is the whole rate.
That predictability is the real difference between time of use and its dynamic cousin. The prices are fixed, so a hot afternoon costs you the same peak rate as a mild one, whether the grid is straining or not.
Time of use vs real-time pricing
Time of use and real-time pricing are both time-varying rates, and they answer opposite instincts. Time of use trades accuracy for certainty: a few fixed windows, known in advance, that only roughly track what electricity actually costs hour to hour. Real-time pricing trades certainty for accuracy: the price changes every hour with the actual market, so cheap hours are genuinely cheap and scarce hours are genuinely expensive.
In ComEd territory, the widely available time-varying residential rate is the dynamic one: ComEd Hourly Pricing, formally called Real-Time Pricing, where the price moves with the wholesale market every hour. You can watch today's prices move live to see how a dynamic rate behaves compared to a fixed window schedule.
What decides whether a time-varying rate pays
The same thing decides it for time of use plans and real-time pricing alike: when your home uses power. Both rate styles reward the same shape, usage that leans overnight and stays light on summer weekday afternoons, and both punish the opposite shape. A home with an electric vehicle charging at midnight has the friendly shape. A home that runs air conditioning hard from three to eight on July weekdays does not, and no rate schedule changes that; it just changes how visibly the afternoon costs.
This is why the honest first step is not choosing a plan, it is knowing your shape. Our free interval data analysis tool reads your own meter export and shows exactly that: your load profile hour by hour, your always-on floor, and how much of your summer use lands in the expensive afternoon window. That is a fact about your home, not advice, and it is the fact every time-varying rate decision rests on.
What are time of use electricity rates?
A rate structure where the price per kilowatt hour depends on the time of day. The utility publishes fixed windows, typically peak, off-peak, and sometimes shoulder, with a fixed price for each. Usage in each window is billed at that window's price, so the same kilowatt hour costs more at 5 pm than at 2 am.
Do time of use plans save money?
They save money for homes whose usage already leans into the cheap windows or can genuinely move there, and they cost money for homes concentrated in the peak window. There is no universal answer, because the plan prices hours and every home fills those hours differently. The deciding fact is your own usage shape, which your interval data shows directly.
What is the difference between time of use and real-time pricing?
Time of use uses a few fixed price windows published in advance; real-time pricing changes the price every hour with the wholesale market. Time of use is predictable but only roughly tracks real costs. Real-time pricing follows real costs closely but moves constantly. Both reward overnight-leaning usage and both are decided by the same thing: when you use power.
What hours are peak for electricity?
For most utilities the peak window falls on weekday afternoons and evenings, commonly somewhere between 2 pm and 8 pm, when air conditioning and household activity stack on top of each other. Overnight hours are off-peak, and weekends are usually off-peak all day. The exact boundaries are published by the utility offering the plan.
Does ComEd have time of use rates?
ComEd's widely available time-varying residential rate is Hourly Pricing, a real-time rate where the price changes hourly with the market rather than by fixed windows. The mechanics, the live prices, and what decides whether it pays for a specific home are covered across this section.
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