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We do not sell energy. We take no commission. Nothing here is a projection. Every number already happened.

We put six real ComEd commercial bills next to each building's own meter data. The demand the meter measured matched the demand ComEd billed, every time. One bill did not match, and we refused to reconcile it.

What we found

  1. On six real ComEd commercial bills, the demand measured by each building's own meter equaled the demand ComEd billed, within 0.004 kilowatts.
  2. The demand charge recomputed from ComEd's published rate matched each bill within ComEd's own rounding, and to the cent on the 2026 restructured bill.
  3. On two buildings, the highest reading of the whole billing period fell outside the 9 AM to 6 PM on-peak window and was never billed. The demand charge is a rule about a window, not the building's physical maximum.
  4. One bill did not reconcile because its interval data belonged to a different building. Phantom Grid declined to reconcile it rather than force a match.
One building, one day
ON-PEAK WINDOW9 AM to 6 PM, the only hours demand is billed0153045kW12a6a9a12p6p12a41.94 kW at 8:30 AMthe day's highest reading, never billed40.91 kW at 9:00 AMthe first on-peak reading, and what set the charge
One summer weekday at Site A, a building of about 41 kW across two meters. Measured by the building's own meter in 30-minute intervals; anonymized to time of day. Each point is one 30-minute reading. The demand charge is set only inside the shaded 9 AM to 6 PM window, so the day's highest reading at 8:30 AM was never billed and the 9:00 AM reading was. This is how the tariff is written. It is not a billing error.
The bill we refused to reconcile

One site did not reconcile, and the instrument declined to reconcile it rather than force a match.

The interval file in one site's folder did not belong to its bill: it was a byte-for-byte copy of a different, larger site's export (about 92 kW), while the bill was a 13 kW site on a different account and meter. Reconciliation was refused. A negative result, "this data is not this site's data," is a valid, load-bearing output: the instrument declines to reconcile mismatched inputs instead of manufacturing a false match.

Every bill, side by side

SiteDelivery classMetersSeasonMeasured kWBilled kWDifferenceBill demand chargeResult
ASmall Load (under 100 kW)2summer40.9140.910.00$596.88Matches the bill
BMedium Load (100 to 400 kW)*1early fall91.94491.94+0.004$1,374.50Matches the bill
CMedium Load (100 to 400 kW)4mid-summer242.568242.57-0.002$3,619.14Matches the bill
DSmall Load (under 100 kW)1fall22.9222.920.00$334.40Matches the bill
ESmall Load (under 100 kW)1spring2026 format46.2046.200.00$597.37Matches to the cent
FSmall Load (under 100 kW)1fall22.5022.500.00$328.28Matches the bill

6 real ComEd commercial bills, reconciled against each building's own 30-minute interval data. Measured demand is the highest total across the building's meters during on-peak hours (9 AM to 6 PM, weekdays). No customer names, addresses, or account numbers.

* ComEd sets a site's delivery class on its trailing-twelve-month peak, not the billing month's. A site drawing under 100 kW this month can still be billed on the 100 to 400 kW class if it crossed 100 kW earlier in the year.

The window, again. On Site B a reading at 7:00 PM, after the 6 PM close, was the true high point of the whole billing period and carried no demand charge, while a lower on-peak reading set the bill. This is how the tariff is written, not a billing error.

Demand Charges

ComEd Demand Charges, Reconciled to the Meter

Six real ComEd commercial demand charges, each reconciled against the site's own interval data. The measured on-peak demand equals the billed demand exactly, and the charge matches within ComEd's own rounding. Plus the one bill we refused to reconcile.

UPDATED AUG 25 2026

The exhibit above is not a projection or a model. Every row is a real ComEd commercial bill set beside the building's own 30-minute interval data, with the Distribution Facilities Charge (the demand charge, on the delivery side of the bill) recomputed from the tariff and checked against what the bill actually charged.

Why is this a reconciliation and not an estimate?

A reconciliation starts from the bill you were actually charged and proves, or fails to prove, that the meter data accounts for it. A calculator does the opposite: it multiplies a number you type in by a rate. The bill shows you only the result of the demand charge, never the single half hour that set it, nor whether that half hour fell inside the on-peak window. Putting the bill and the interval data back together is what makes the charge legible.

Why did we refuse to reconcile one bill?

Because its interval data did not belong to it. The file was a copy of a different, larger building's export, so the meter data and the bill described two different places. The instrument returned "this does not reconcile" rather than the confident number it could have produced from mismatched inputs. An engine that always hands back a confident answer is not honest, only confident. The ability to say no is what makes the other six results worth anything.

What we publish, and what we keep

Every result on this page is yours to check: the demand each building's own meter measured, the demand ComEd billed, the bill's own charge, and the structural findings about the on-peak window. The rates and the on-peak rule are ComEd's, filed and public (ComEd Ill. C.C. No. 10, Rider RDS, and ICC Docket 24-0378), so you can hold every number against the tariff yourself and take nobody's word for it. The engine that reproduces a bill to the last cent stays behind the instrument, and that costs you nothing: checking these results takes the tariff, which is public, and not the engine, which is not.

Reconcile your own bill

You can run the same reconciliation on your own ComEd bill, to the cent, with the free demand charge tool. We do not sell energy and we take no commission. If you have the bill but not the interval file yet, the free bill reader reads the ComEd bill PDF, rebuilds every charge, checks it against what ComEd printed, and offers to request the interval data from ComEd.

The demand charge is the line these six bills were reconciled against, and on a commercial account it appears as the Distribution Facilities Charge. Whether a past peak follows you into later months depends on the ratchet, which the standard ComEd commercial classes do not carry. We have reconciled the rest of the bill too: every line on a ComEd bill covers the rider and adjustment block against the filed tariff.

What does "reconciled" mean here?

That the measured demand from the site's interval data equals the demand ComEd billed, and the charge recomputed from the tariff matches the bill. On these six sites the demand matches exactly and the charge matches within ComEd's own per-line-item rounding; on the 2026 restructured bill it matches to the cent.

Are these real bills?

Yes. Every row is a real ComEd commercial account, anonymized: no names, addresses, or account numbers. The figures are the actual billed demand and the actual Distribution Facilities Charge.

Why did one bill not reconcile?

Its interval file did not match its bill: the data was a copy of a different, larger site's export. Rather than manufacture a match, the instrument declined to reconcile. A refusal is a valid result, not a failure.

Can a demand charge be set by an interval I never think about?

Often, yes. On two of these sites the highest reading of the period fell outside the 9 AM to 6 PM on-peak window and was never billed, while a lower on-peak interval set the charge. The demand charge is a rule about a specific window, not the site's physical maximum.