ComEd Hourly Pricing: Turning Daily Wholesale Rates Into Savings
ComEd Hourly Pricing bills Chicago-area households at the actual wholesale electricity price, which changes every hour of every day. There is no fixed peak window and no off-peak block — just twenty-four different prices, published the afternoon before.
On June 29, 2026, that meant power cost about 2¢/kWh overnight and passed 60¢/kWh between 7 and 8 p.m. — roughly a thirtyfold swing inside a single day.
ComEd serves Chicago, Cook County and the rest of northern Illinois, and its Hourly Pricing program is voluntary: most customers are on a fixed supply rate by default and have to opt in. It rewards automation more than almost any residential rate in the country, for the reason the numbers above suggest.
This guide explains how Hourly Pricing works, why it’s a great fit for a smart home, and how to capture the savings you can’t realistically chase by hand.
How ComEd Hourly Pricing works
On the standard fixed rate, you pay one supply price no matter when you use power. On ComEd’s Hourly Pricing program, you pay the hourly wholesale market price set by the regional grid operator (PJM), plus the same delivery charges, taxes, and fees every ComEd customer pays — roughly 8¢/kWh on top of the wholesale price under the standard delivery rate.
ComEd also offers an optional Delivery Time-of-Day plan that replaces that flat 8¢/kWh with a delivery charge that varies by time of day instead. It stacks with Hourly Pricing, so the two together price both halves of your bill — supply and delivery — by time of use.
Two things make this different from time-of-use:
- The price changes daily. Tomorrow’s hourly prices are published the afternoon before, so a cheap 2 a.m. tonight might be a different number tomorrow. There’s no fixed schedule to memorize.
- The swings can be large. Overnight and midday hours are often just a few cents per kilowatt-hour of wholesale cost; hot summer evenings can spike well above that. The shape of the curve is different every day.
What the hourly price actually does across a day
“No fixed schedule” is true, but it is not the same as “no pattern.” The price is set by supply and demand on the PJM market, and both follow the clock more closely than the day-to-day variation suggests. A typical northern Illinois weekday runs roughly like this:
| Hours | What is happening on the grid | Typical shape |
|---|---|---|
| Midnight – 6 a.m. | Demand at its daily floor, carried largely by nuclear baseload | The cheapest stretch most nights |
| 6 – 9 a.m. | Morning ramp as Chicago wakes up | Rising |
| 9 a.m. – 3 p.m. | Commercial load steady; solar contributes in summer | Moderate |
| 3 – 7 p.m. | Air conditioning peaks as people get home | The most expensive stretch |
| 7 p.m. – midnight | Demand unwinds through the evening | Falling back toward the overnight floor |
Illinois has an unusually large nuclear fleet, and it matters here: nuclear plants run flat out around the clock, which puts a steady, cheap floor under the overnight hours. That is a structural reason the small hours are reliably the cheapest ones, rather than a coincidence of any particular night.
The important qualifier is that this is a tendency, not a timetable. The trough might land at 1 a.m. tonight and 4 a.m. tomorrow. A mild, breezy spring day can be nearly flat, with barely enough spread to be worth acting on; a still, humid July evening can put the 6 p.m. hour thirty times above the 3 a.m. one, as the chart below shows.
Three things move the curve more than anything else:
- Temperature, because air conditioning is the largest swing load on a summer grid — and in a Chicago winter, electric heating and the early-dark evening peak do something similar.
- PJM-wide conditions, not just Illinois. ComEd sits inside a market stretching to the mid-Atlantic, so a heat wave in Pennsylvania or New Jersey can lift your 6 p.m. price.
- The day of the week, because commercial and industrial demand drops at weekends — which is why Saturday afternoons are often cheaper than Wednesday ones.
What this means in practice: you cannot set one timer and be done, but you also cannot ignore the shape. Keep large flexible loads out of the late-afternoon block and push them toward the overnight trough, then adjust the exact hour against the prices published the day before.
A single day on ComEd Hourly Pricing (June 29, 2026): overnight power costs about 2¢/kWh, then the 7–8 p.m. spike jumps to 44¢ and past 60¢. The cheapest and most expensive hours are only hours apart.
Tomorrow’s hourly prices are published the afternoon before. July 1’s day-ahead curve peaks above 60¢/kWh at 6–8 p.m. — seeing that in advance is exactly what lets a schedule plan around it.
That’s the opportunity and the problem in one sentence: the savings are real, but they move.
Where the savings are
Because the cheapest hours shift day to day, the wins come from reacting to each day’s price curve:
- EV charging during whatever the cheapest overnight stretch happens to be tonight. Not a fixed “after midnight” rule, but the actual low point.
- Pre-cooling or pre-heating ahead of the hours your forecast says will be expensive, so your HVAC coasts through the spike.
- Water heating and battery charging timed to the day’s troughs and away from its peaks.
On a fixed time-of-use plan, “off-peak” is the same every day and you can set a static timer. On Hourly Pricing, the best schedule is genuinely different tomorrow than it was today, which is exactly why a static timer leaves money on the table.
How to capture it: by hand vs. automatically
By hand, you’d check tomorrow’s published hourly prices each afternoon, cross-reference the weather, and reprogram your thermostat, EV charger, and water heater accordingly — every day. Almost nobody sustains that. And even if you did, you’d still be eyeballing how much pre-cooling your house actually needs.
Automatically is the whole point of a rate like this. Hungry Machines pulls the next day’s hourly prices, combines them with tomorrow’s forecast plus a custom model of your home, then builds an optimized schedule each night. It charges the EV in the genuine overnight trough, pre-cools just enough to skate past the expensive hours, and times your water heater and battery to the day’s cheapest energy. Then it does everything again tomorrow against tomorrow’s new prices.
Against a day with a steep evening spike, Hungry Machines pre-cools in the cheap morning hours (blue line) and lets the room drift up through the expensive evening — staying inside the comfort band the whole time. Result: 63% off that day’s cooling cost.
A milder day with a smaller spike calls for a gentler pre-cool right before the evening peak. Same limits, same automation, 33% saved. The right amount of pre-cooling changes every day, which is why a static timer leaves money on the table.
In this situation, automation is the only realistic way to capture what the rate offers.
Do peak rates apply on weekends?
On Hourly Pricing the question doesn’t apply — there is no peak window at all. ComEd Hourly Pricing has no 4–9 p.m. block, no weekday/weekend split, and no calendar rule of any kind. Saturday at 6 p.m. is priced by that hour’s wholesale market, exactly like every other hour.
That is a real difference from a time-of-use plan, not a technicality. On a fixed plan you can answer “when is power expensive?” once and set a timer. On Hourly Pricing the expensive hours are wherever demand and generation put them that day — and weekend afternoons are often cheaper than weekday ones, because commercial and industrial demand drops.
So the honest guidance inverts. Rather than memorising a window, you want tomorrow’s published prices, which arrive the afternoon before. The cheapest weekend hour and the cheapest weekday hour are found the same way: by reading the curve. That is a daily task, which is why it suits automation rather than habit.
Common questions
Is ComEd Hourly Pricing risky?
Your price follows the market, so a rare spike costs more in that hour. On June 29, 2026, the wholesale price ran near 2¢/kWh overnight and passed 60¢ between 7 and 8 p.m. — a 30× swing inside one day. That number is the risk and the opportunity in the same sentence.
The exposure is smaller than it looks, for two reasons. Spikes are concentrated in a handful of summer evening hours, and you capture every cheap hour in between — which is most of them. What turns the volatility from a hazard into an advantage is moving flexible load away from the spikes, because the same 30× spread that punishes an unmanaged home rewards a scheduled one.
The honest caveat: on a fixed rate you cannot lose to a price spike, and a household with no flexible load and no automation has little to gain here.
How is this different from time-of-use?
Time-of-use has fixed daily price blocks — PG&E’s 4–9 p.m. peak is the same 4–9 p.m. tomorrow, next week, and next July. You can learn it once, set a timer, and be roughly right forever.
Hourly Pricing has a brand-new price for all 24 hours, published the afternoon before. There is no schedule to memorise, because there is no schedule. The cheapest hour tonight might be 2 a.m.; tomorrow it might be 11 a.m. because wind generation is high and demand is low.
That difference decides what a good strategy looks like. On time-of-use, a static timer captures most of the available savings. On Hourly Pricing a static timer captures some of it and misses the rest, since it cannot know that tomorrow’s trough moved six hours.
Do I need an EV or battery to benefit?
No, though they help most. An EV is the ideal load for this rate because it is large, entirely flexible about when it charges, and needs the same kilowatt-hours regardless — so moving a 40 kWh charge from a 60¢ hour to a 2¢ hour is close to free money.
But pre-cooling a home with central AC captures meaningful savings on its own. Your house is already a thermal battery: cool it while power is cheap and it coasts through the expensive hours, no hardware required. A water heater does the same thing with hot water.
What actually determines the benefit is not which appliance you own but how much of your consumption is time-flexible. A home whose usage is mostly lighting and electronics has little to shift, whatever else is in the garage.
ComEd’s High Price Alerts
ComEd emails or texts an alert whenever the price holds at or above 14¢/kWh for four consecutive 5-minute windows — a signal that the current stretch is genuinely expensive, not just above average. You can sign up for the alerts directly at hourlypricing.comed.com.
Hungry Machines doesn’t need the alert to act on it. The nightly schedule is built from tomorrow’s published price curve, so on a normal day it has already moved flexible load out of the hours a threshold like that would fall in — pre-cooling ahead of a hot afternoon, or holding EV charging for the overnight trough. ComEd Peak Time Savings rewards the same behavior directly: a bill credit for staying below your recent average during the hottest event days of the year, and it stacks with Hourly Pricing.
Next steps
Prefer fixed daily windows to a new price every hour? ComEd Time-of-Day Pricing covers the same territory with four set periods that repeat every day, and Delivery Time-of-Day does the same for just the delivery charge, stacking with Hourly Pricing. Downstate Illinois, on Ameren rather than ComEd? Ameren’s Power Smart Pricing is the same hourly idea for central and southern Illinois. If your utility uses fixed time-of-use blocks instead, the approach is a little different — see our guides for PG&E, SDG&E, SCE, and ConEd in New York. Outside the US, the same day-to-day pricing drives Octopus Agile in the UK and Australia’s wholesale market. For the software category itself, see our guide to home energy management systems.
To let your home react to ComEd’s prices automatically, see how Hungry Machines works and sign up now.
For the cross-utility picture, see the cheapest time to run your appliances and whether peak rates apply on weekends.