The record
What has actually happened to the power here
Three events in five years, each dated, each sourced, with the number of customers affected and how long restoration took. Read it before deciding how urgent a generator is for your address — and read the reliability figures underneath it, because they do not describe these days at all.
The dated record
10 August 2020
Midwest derecho
- Winds above 80 mph across the Chicago area.
- More than 800,000 ComEd customers lost power initially, and 263,140 were still without it more than 24 hours later.
- In DuPage County specifically, 58,000 homes were without electricity.
- Most restoration was complete by 14 August with some areas on 15 August — roughly four to five days end to end, using 1,500 technicians brought in from around the country.
Source: ABC7 Chicago and ComEd news release.
20–21 June 2021
EF-3 tornado, Naperville to Woodridge
- Rated EF-3, peak winds 140–165 mph, on a 14.8-mile path up to 600 yards wide.
- It began near 75th Street and Springbrook Prairie and tracked through Naperville, Woodridge, Darien and Burr Ridge.
- 900 structures were affected, 300 significantly damaged and 29 left uninhabitable.
- More than 22,000 DuPage County customers lost power, including over 6,000 in Woodridge.
- It was the first EF-2 or stronger tornado in the Chicago metro since June 2015.
Source: NWS Chicago and ComEd reporting.
14–16 July 2024
Derecho sequence
- Non-tornadic downburst gusts of roughly 90 mph across DeKalb, Kane and DuPage Counties.
- Geographic impact comparable to the August 2020 derecho.
Source: contemporaneous reporting.
Taken together these are the events that empty a freezer, stop a sump pump through a storm that is also filling the basement, and leave a home without heat or cooling for days rather than hours.
Observed pattern, not a forecast: DuPage County sees roughly one to three significant severe weather events a year capable of causing multi-day outages. Nothing here predicts what any future year will bring.
Why the reliability figures look so good
ComEd reports system average interruption duration to the Illinois Commerce Commission, and the numbers are genuinely low. They are also measured with Major Event Days removed.
| Year | SAIDI, excluding Major Event Days |
|---|---|
| 2021 | 59.6 minutes per customer |
| 2022 | 36.3 minutes per customer |
| 2023 | 37.9 minutes per customer |
Source: Illinois Commerce Commission performance metrics, dockets P2025-0383 and P2025-0514. The ICC target for 2033 is 31.5 minutes, a mandated 15% reduction.
Both things are true at once, and that is the point. On an ordinary year the grid here is reliable by the measure the regulator uses. The days that make people buy generators are the days that measure excludes — so a homeowner who has read about record reliability and then spent four days without power in August is not confused. They are looking at two different questions.
The outage and the water arrive together
The local detail that matters most here is not the length of the outage. It is that the storm causing it is the same storm filling the basement. DuPage County glacial till is clay, clay holds water and transmits pressure against foundations, and a sump pump without power during a heavy rain is the failure mode people actually experience.
The City of Naperville itself recommends backup power for sump pumps in its guidance on home flooding, explicitly linking power outages to sump failure risk. DuPage County operates more than fifteen major flood control facilities, including the Fawell Dam on the West Branch DuPage River.
That pairing is why the sump circuit is usually the first thing to settle when deciding what a generator here needs to carry, and it is a large part of what the worth-it calculation is actually protecting. Duration is also what separates the two machines: whole-house or portable turns almost entirely on how long the power stays off and whether anyone is home to work a portable while it is.
What this page does not do
It does not forecast. Three events in five years is a record, not a rate, and no figure here indicates what the next storm season holds for your address. It does not describe outages at properties served by a municipal utility rather than ComEd — most Naperville addresses are on Naperville's own electric utility, and their reliability record is a separate matter. And it makes no claim that a generator would have carried any particular home through any of these events, which depends entirely on what was installed and what it was asked to run.
Decide what you want covered
If the record above describes days you have already had, the next question is which circuits you want running through the next one. Tell us the property and what matters most, and we will get the request to installers covering your part of the region.
Installation by town
Generator installers by town
Permit fees, inspection steps and the utility you deal with change from one suburb to the next. These pages carry the local details.