Find the energy number.
On a US EnergyGuide label, look for estimated yearly electricity use in kWh. The dollar figure depends on electricity prices and is not an energy measurement. The FTC’s label guide explains what the label represents and where to find one.
A plug-in energy meter can provide a reading for your own conditions. Enter the kWh accumulated over a full 24-hour period; a momentary watt reading is a different input. A single day may miss changes in temperature, defrost cycles or normal use.
From a label to a load.
Average watts from a yearly label = annual kWh × 1,000 ÷ 365 ÷ 24. For a 24-hour meter reading, average watts = measured kWh × 1,000 ÷ 24. These averages already include on/off usage over their measurement or estimate period, so we do not apply a second generic duty-cycle reduction.
The planner needs running watts and usage separately. We divide the average by your running watts and round usage upward to a whole percentage. That can slightly increase the energy estimate. Both the original average and the planner’s average are shown above.
Walk through the example.
438 kWh per year is 1.2 kWh per day, or 50 W on average. With 150 W entered as the running load, that implies 33.33% usage; the planner rounds it up to 34%, giving 51 W. Adding 10 W of station idle draw brings the modeled load to 61 W.
For 12 hours, that is 732 Wh. At 80% usable capacity and full starting charge, the modeled nominal requirement is 915 Wh. The 900 W startup example is checked separately against the station’s output.