Yes, on Hourly Pricing they are, and the size of the gap is something you can measure rather than assume. On ComEd's flat rate the price is the same at 3 AM as at 3 PM. On ComEd Hourly Pricing you pay the wholesale price for each hour, and the wholesale price at night is set by the plants that run when almost nobody is using power. This page gives you the measured overnight number, what it leaves out, and the one question that decides whether your house is the kind that benefits from it.
What ComEd hourly prices look like overnight
We hold the settled hourly price for the ComEd zone, the same PJM series ComEd invoices Hourly Pricing on, for every hour from June 2025 through July 2026. That is 10,228 hours. Averaged across all of them:
- Overnight, 10 PM to 6 AM: 2.51 cents per kWh
- Afternoon, 2 PM to 7 PM: 5.80 cents per kWh
- Every hour of the day: 3.90 cents per kWh
So the overnight price ran at less than half the afternoon price over fourteen months, and about two thirds of the all-hours average. That gap held in every month of the record. In the mildest month, April 2026, overnight averaged 1.86 cents against 2.13 in the afternoon. In the hottest, July 2026, it was 3.09 against 14.58.
These are energy prices before ComEd's own adjustments. The bill applies a distribution loss factor of 5.17 percent and two small uncollectible cost factors on top, so the price on a Hourly Pricing bill runs a little above the figures here. The shape does not change.
What the overnight price leaves out
The cheap overnight number is the supply price only. Delivery charges, the customer charge, taxes and riders are billed the same way on Hourly Pricing as on the flat rate, at every hour, so they do not get cheaper at night. And Hourly Pricing bills carry a separate capacity charge, set by your draw during the five highest demand hours of the prior summer. Overnight use does nothing to that charge in either direction; all ten of the peak hours on file for the last two summers fell on weekday afternoons.
The comparison people actually want is against the flat rate, and the flat rate is not 3.90 cents. ComEd's Price to Compare is 10.399 cents per kWh from June 2026. But that number bundles capacity and other supply costs that Hourly Pricing bills as separate lines, so putting 2.51 next to 10.399 overstates the saving. The honest comparison prices your own hours on both rates, capacity included, which is what is Hourly Pricing worth it is about.
Who the overnight price is for
The overnight price only helps if you can move meaningful energy into those hours. For most homes that means one thing: an electric vehicle. A car that charges from 11 PM to 5 AM puts most of its energy into the cheapest hours in the record, and a car is often the single largest load in the house. Electric water heaters on a timer and pool pumps are the other common candidates. Lighting, cooking and television are not, because they happen when you are awake.
The other half of the question is what your house does in the afternoon. A home that charges a car overnight and also runs air conditioning hard from 2 to 7 PM in July is buying its cheapest hours and its most expensive hours in the same month. Whether that nets out in your favor depends on how much of each you use, and the only place that answer exists is in your own interval data.
Are ComEd rates lower at night on the standard rate?
No. On the default flat rate the supply price is the same in every hour. The overnight discount exists only on Hourly Pricing, where the price follows the wholesale market hour by hour.
What hours are cheapest on ComEd Hourly Pricing?
Across the fourteen months we hold, the cheapest hours cluster between about 1 AM and 5 AM. Those are also the hours when the price most often falls below zero; what happens when the ComEd hourly price goes negative covers that separately.
Is charging an EV overnight on Hourly Pricing cheaper than the flat rate?
For the energy in the car, almost always, because 2.51 cents against a flat supply rate above 10 cents is a wide gap. For the whole bill, it depends on the rest of the house, especially summer afternoons and the capacity charge those set. The car helps; the air conditioner decides.
Does the overnight price change by season?
Yes, but less than the afternoon price does. Overnight averaged between 1.79 cents (January 2026) and 3.09 cents (July 2026) across the record. The afternoon ranged from 2.13 to 14.58. Summer widens the gap by raising the afternoon, not by lowering the night.