It depends on your utility’s bill and portal, which is why this page cannot show a universal screenshot. What you want is maximum demand in kilowatts (or amps) over the previous 12 months, preferably from 15-minute interval data, not a monthly total of kilowatt-hours. kWh tells you how much energy you used; peak kW tells you the highest rate of use, which is what the existing-loads method starts from. Many residential bills never print a demand figure at all. When they do, the label may be “peak demand,” “maximum kW,” “interval demand,” or something equally local.
A practical search order:
- Log in to the utility portal and look for usage, interval, Green Button, or AMI data. Export a year if you can, and find the highest kW reading. Watch the interval length: hourly averages can hide a short peak that a 15-minute reading would show.
- Read a year of PDF bills for a demand line. Do not confuse a peak charges time-of-use period with a measured kW demand.
- Call the utility and ask for the 12-month maximum demand at the meter, in kW. Say it is for an electrical load calculation.
If you have rooftop solar, ask whether the number is net imported kW or a gross measurement — see the solar-and-measured-demand page. Convert kW to amps at 240 V by dividing the watts by 240 (a 9.6 kW peak is 40 A). Then use the calculator’s measured-demand mode. The electrician and the AHJ still decide whether the data qualifies.
This is not a permit calculation, a utility approval, or a substitute for a licensed electrician, HVAC contractor, or the authority having jurisdiction. Panel Headroom is an independent educational site. It is not a utility, a certification body, or a contractor. Electrical and generator work that is done incorrectly can cause fire, shock, or carbon monoxide poisoning. Use the adopted electrical code and manufacturer instructions; pull permits where required.