Watt & Worth

Two-appliance ownership comparison

Compare two written purchase estimates over the same planning period.

Editable illustrative defaults · not current prices or rates. Use nonnegative finite values; comparison period up to 100 years. Results update as you type. JavaScript is required for interactive calculation; the formula and worked example are below.

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years
A · Planned total cost
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B · Planned total cost
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Difference (B minus A)
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B running-cost payback
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Illustrative estimate only — not an offer or quote.

Compare the same job

Use two real quotes for appliances that meet your capacity, fit and installation requirements. Enter a tax-inclusive purchase price and all delivery, installation and haul-away costs for each. Add annual electricity, water, subscriptions and consumables in the annual field, avoiding double counting. The defaults are illustrative numbers, not quotes or typical market prices.

Formula and illustrative example

Planned cost = purchase + installation + annual running cost × years. A is $800 + $150 + ($100 × 10) = $1,950. B is $1,050 + $150 + ($60 × 10) = $1,800. B minus A is −$150, so B costs $150 less over that scenario. The extra $250 up front divided by $40 annual savings gives a simple payback of 6.25 years.

What is excluded

These are undiscounted cash amounts with constant annual costs. Repairs, financing, changing utility rates, resale and uncertain rebates are excluded unless you intentionally include documented costs. Payback does not predict durability. A cheaper option that fails the fit or safety checks is not a valid alternative. If B does not save annual running cost, the tool reports no running-cost payback rather than inventing a date.

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