Load Factor by Building Type: Worked Examples

Load factor is the shape of a building's electricity use compressed into one number: average demand divided by peak demand over a billing period. Building type is a decent predictor of shape, because a cold store and a machine shop do different things with power at different hours. It is not a measurement. The examples below run five building types through the same formula so you can see what each shape produces, and one of them is a real site measured on a reconciled ComEd bill rather than an illustration.

If you want the formula itself explained first, what load factor is and how it is calculated covers it. If you want your own number, the load factor calculator works it out from two figures on your bill.

The formula every example uses

Load Factor = kWh used / (Peak kW x hours in the period)

A 30 day billing period is 720 hours. The numerator is the energy the building actually used. The denominator is what it would have used running at its single highest interval for the whole month. So every example below is the same question asked of a different shape: how close does normal operation come to the peak?

The four illustrations that follow use round numbers chosen to show the arithmetic. They are not typical values for those building types and they quote no rate. The distillery at the end is measured.

A one shift machine shop

Suppose a shop runs one shift, five days a week, and starts several large machines within the same half hour most mornings. Say it uses 12,000 kWh in a 30 day month and its highest 30 minute interval is 80 kW.

Load Factor = 12,000 / (80 x 720) = 12,000 / 57,600 = about 21 percent

The building is dark two thirds of the hours in the month and its peak happens when everything starts together. Both of those push the number down. Nothing about a 21 percent figure is wrong for a shop like this; it is what that shape looks like.

An office building on business hours

Suppose an office uses 45,000 kWh in the month and peaks at 150 kW on a hot afternoon when the cooling plant and every workstation are running.

Load Factor = 45,000 / (150 x 720) = 45,000 / 108,000 = about 42 percent

Offices sit in the middle. They run hard for roughly ten hours on weekdays, carry a lighting and equipment base overnight, and their peak is usually weather driven rather than process driven. A weekend building automation schedule moves this number more than most people expect, because it changes the numerator without touching the peak.

A restaurant with a lunch and dinner peak

Suppose a restaurant uses 30,000 kWh and peaks at 75 kW during a dinner service when the kitchen line, dish machine, walk in coolers and dining room cooling all coincide.

Load Factor = 30,000 / (75 x 720) = 30,000 / 54,000 = about 56 percent

Refrigeration never stops, which keeps the average up, and the two service peaks are broad rather than spiky. Restaurants often land higher than their owners guess for exactly that reason: the coolers do the work overnight.

Cold storage running around the clock

Suppose a cold storage warehouse uses 120,000 kWh and peaks at 200 kW when compressors stage up together on a warm afternoon.

Load Factor = 120,000 / (200 x 720) = 120,000 / 144,000 = about 83 percent

This is the high end. The building draws close to its peak at every hour of every day, so the peak that sets the demand charge is spread over a very large number of kilowatt hours. The same demand charge costs far less per kWh here than at the machine shop, and load factor vs demand charge works that arithmetic through on a real bill.

A distillery, measured on a reconciled ComEd bill

This one is not an illustration. A distillery in ComEd territory, billed as a Small Load delivery account under 100 kW, used 3,873 kWh over a 30 day period ending in September 2025. Its billed site coincident peak demand was 40.91 kW, set in the 30 minute interval beginning 9:00 AM on a Friday as the morning ramp crossed into the on peak window. The bill was reconciled to the cent against the meter's own interval data.

Load Factor = 3,873 / (40.91 x 720) = 3,873 / 29,455 = about 13 percent

Thirteen percent. A batch process building that runs hard for a few hours a few mornings a week and idles the rest of the month produces a number below every illustration above, and below every commonly quoted range. That is the point of including it. The 40.91 kW peak set a $596.88 Distribution Facilities Charge, which was 60 percent of the whole bill, and it did so in a month where the building used less energy than the machine shop illustration.

Six ComEd businesses, measured for three years

The illustrations above are arithmetic. These are meters. Six ComEd commercial accounts, three years of 30-minute data each, load factor worked out for every month from the site's own kWh and its highest half hour. Sites are named by type only.

business	months	load factor, lowest / typical / highest month	overnight floor, typical	floor as share of energy
print shop, four meters	35	32 / 47 / 55 percent	42 kW	46 percent
bowling alley	35	33 / 45 / 58 percent	15 kW	41 percent
weekend-peaking site	41	31 / 41 / 57 percent	11 kW	57 percent
seasonal retail site	34	19 / 34 / 51 percent	2 kW	34 percent
distillery, two meters	35	6 / 15 / 30 percent	2 kW	35 percent
auto repair shop	34	9 / 15 / 25 percent	0.3 kW	10 percent

Two things stand out. The first is how wide each building's own range is: the same distillery ran from 6 percent to 30 percent depending on the month, and the seasonal site from 19 to 51. A single load factor describes one billing period, not a building. The second is what drives the high end. The three sites above 40 percent all carry a large always-on floor, 11 to 42 kW, that keeps the average up overnight. The auto shop at 15 percent has almost nothing running when it closes, and the distillery's 2 kW floor is small against peaks of 40 to 60 kW. The 13 percent measured on the distillery's September 2025 bill, above, sits inside its own range, a little under its typical month.

The hour the peak lands, by business type

The same six meters also answer where the monthly peak happens, which is the half hour a demand charge is built on.

business	most common hour of the monthly peak	months in that two-hour band
auto repair shop	9 AM	41 percent
distillery	10 AM	71 percent
seasonal retail site	11 AM	29 percent
weekend-peaking site	12 PM, Saturday or Sunday	63 percent
print shop	1 PM	54 percent
bowling alley	7 PM	60 percent

Morning starts for the shops that switch everything on at once, midday for the production building, evening for the one whose customers arrive after work. Whether the tariff bills that hour is a separate question: ComEd's window is 9 AM to 6 PM on weekdays, and how often the demand charge missed the real peak works through what that meant for each of these six.

What the building type tells you, and what it does not

The ranges usually quoted, industrial 60 to 90 percent, commercial 30 to 60, highly variable loads under 30, are rules of thumb. They are useful for guessing which end of the scale a building sits on before you have a bill. They are not measurements, and the one measured site on this page sits under all of them.

What the type predicts is the shape: how many hours the building runs, and whether its peak is a process event or a weather event. What it cannot tell you is the number, because two buildings of the same type with the same equipment can differ by whether their big loads start together or ten minutes apart. The bill can tell you that. Interval data can tell you which half hour did it. The type can only tell you where to look first.