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Appliance running cost comparison calculator

Replacing a working appliance only pays if the energy saving beats the purchase price within its life.

per kWh
years
Payback period
4.58years
= Exact Reasonable payback
Annual saving
98.18
Net saving over its life
531.79
Existing running cost
153.41
Replacement running cost
55.23
Energy saved per year
350.6 kWh
Running cost reduction
64.0 %
Pays back within its life
1
Show the working
  1. Existing appliance power = 250
  2. Replacement power = 90
  3. Hours per day = 6
  4. Electricity price = 0.28
  5. Cost of the replacement = 450
  6. Expected life = 10
  7. Existing running cost = 250/1000 * 6 * 365.25 * 0.28 = 153.405
  8. Replacement running cost = 90/1000 * 6 * 365.25 * 0.28 = 55.2258
  9. Annual saving = 153.405 - 55.2258 = 98.1792
  10. Payback period = 98.1792 > 0 ? 450 / 98.1792 : 0 = 4.583 46
  11. Net saving over its life = 98.1792 * 10 - 450 = 531.792
  12. Energy saved per year = (250 - 90)/1000 * 6 * 365.25 = 350.64
  13. Pays back within its life = 4.583 46 > 0 && 4.583 46 < 10 ? 1 : 0 = 1
  14. Running cost reduction = 153.405 > 0 ? 98.1792/153.405*100 : 0 = 64

Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.

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    The formula

    • payback = purchase price / annual saving

    Scrapping a working appliance early has an embodied carbon cost that a running-cost calculation never shows.

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