Start with incremental cost
If you must buy an appliance anyway, compare the efficient model’s additional purchase price—not its entire price—with the annual operating savings. Replacing a functioning appliance early requires comparing the full replacement cost and remaining useful life.
Simple payback
Simple payback is easy to understand, but it does not account for financing, repair risk, energy-price changes, resale value, or the time value of money.
Use three scenarios
Calculate conservative, expected, and high-usage cases. A robust purchase usually remains sensible across the range. If the conclusion changes with a small assumption, measure your current device before buying.
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How this page was prepared
PowerCost Lab publishes this page to help readers make a specific electricity-cost decision. Worked figures are recalculated from the inputs shown, assumptions remain visible, and market facts are separated from user-entered estimates.
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