An energy comparison is useful only when the numbers mean the same thing. Start with a documented consumption figure, identify its unit and record the conditions behind it.
Keep energy and power separate
For this worksheet, use energy consumption in kWh per day or per year. Do not substitute a nameplate amperage or wattage value and treat it as measured daily consumption. If you cannot find comparable consumption data, mark the energy comparison as incomplete.
Make the arithmetic visible
Estimated annual electricity cost = kWh/day × operating days/year × electricity rate in USD/kWh.
For illustration only, an entered value of 5 kWh/day, 365 days and $0.15/kWh produces $273.75 per year. This is a hypothetical arithmetic example, not measured performance of a named freezer or a current national electricity price.
The calculator applies this formula to your inputs and can compare two models. A model’s monthly figure is the annual estimate divided by twelve, not a forecast of each monthly bill.
Compare like with like
The DOE’s commercial purchasing guidance explains its energy-cost examples with explicit assumptions. Its published refrigerator example should not be copied as a universal freezer saving. Follow the same principle: preserve the model type, data source and assumptions when comparing figures.
Separate energy cost from ownership cost
A complete purchasing worksheet has separate lines for equipment price, delivery, installation, documented energy cost and the other costs you can substantiate. Do not fill in a lifetime repair estimate or service life without evidence.
The calculator excludes demand charges, taxes, maintenance, financing, tariff changes and differences between test conditions and your site. It therefore cannot tell you which freezer is the best overall purchase.
When the data is missing
Ask the supplier for the energy figure’s source and test basis. Record the answer as pending if it is unavailable. A blank field is more useful than a precise-looking guess disguised as product data.
Source and calculation notes
DOE/FEMP commercial refrigeration purchasing guidance, accessed September 13, 2026. The formula is an energy-cost worksheet; the 5 kWh/day example is hypothetical. No product savings claim is made.