EDITORIAL METHODOLOGY

Every included assumption should be visible

The lab favors a narrow calculation that can be checked by hand. It does not hide omitted costs behind a single precision-looking verdict.

Energy and operating cost

In wattage mode, annual energy equals watts divided by 1,000, multiplied by hours per day, days per week, 365 ÷ 7, and duty cycle. In annual mode, the calculator uses the entered annual kilowatt-hours directly. Annual operating cost equals annual kilowatt-hours multiplied by the electricity rate in dollars per kilowatt-hour.

Comparison and simple payback

Annual savings equal baseline annual cost minus alternative annual cost. Upfront difference equals alternative purchase price minus baseline purchase price. When both values are positive, simple payback equals upfront difference divided by annual savings.

Simple payback is not a complete investment return. A result should be compared with the expected ownership period. If payback exceeds the years a product is likely to remain in service, energy savings alone do not recover the additional purchase cost within that horizon.

Equivalent service comes first

Two products should provide substantially comparable service before their energy costs are treated as alternatives. Capacity, output, climate, operating mode, and required features can matter more than nameplate watts. When service is not equivalent, the lab compares electricity inputs only and cannot determine which product is the better purchase.

Editorial standards

Decision guides distinguish sourced facts from illustrative assumptions, link to primary sources where practical, disclose material exclusions, and avoid claiming that an average rate is a household tariff. We do not invent product tests, professional credentials, or user outcomes.

For a worked application of these rules, read Keep an old refrigerator or replace it?