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Efficiency payback calculator

Is the efficient model worth its higher price? Put two products side by side, choose your state, and read the payback period and the total cost over the years you will keep it. For cordless gear, switch to the battery tab to see what an hour of work really costs.

Electricity price
Using 18.31 c/kWh. Your bill shows your rate.

Residential averages, July 2026: EIA Electric Power Monthly, Table 5.6.A, pulled 2026-10-05.

How do you know the usage?
A bedroom heater running 8 hours a day for 4 winter months is about 960.
Product A (usually the cheaper one)
Rated watts while running.
Product B (the efficient one)
Rated watts while running.
Time
0 keeps today's price flat.

Result

The extra price comes back in 2.2 years. Over 10 years you keep $214.65.

Standard model runs for
$153.80 / year
Efficient model runs for
$126.34 / year
Yearly saving
$27.46
Extra price of B
$60.00
Payback
2.2 years
Total cost of A over 10 years
$1,738.04
Total cost of B over 10 years
$1,523.39

The prefilled numbers are a worked example, not a product listing. Replace them with your own. Runs entirely in your browser; nothing is sent anywhere.

How to use it

  1. Pick your state, or type the cents per kWh from your own bill.
  2. Enter the price of each product and either its watts (with hours of use) or the kWh per year from its label.
  3. Set how many years you will keep it. Read the verdict, then change the price of the efficient model to see where it stops paying off.

The formula

Payback in years equals the extra price divided by the yearly saving. The saving is the difference in annual kilowatt-hours multiplied by your price per kWh. For battery tools the cost per hour is the tool price spread over its hours of use, plus the battery pack price spread over every hour the pack delivers, plus the electricity used to refill it. Read the walk-through in What a 1,500-Watt Space Heater Really Costs to Run.

FAQ

How is the payback period calculated?
Extra purchase price divided by the yearly electricity saving. If the electricity price changes each year, the saving grows or shrinks year by year until the running total covers the premium.
Where do the electricity prices come from?
They are the average residential price per state from the U.S. Energy Information Administration, Electric Power Monthly Table 5.6.A. The page shows the month and the date we pulled them. Your own bill is more exact, so you can type your rate instead.
What does "battery wear" mean?
It is the share of the battery pack price used up by each hour of work: pack price divided by the total hours the pack delivers over its charge cycles. For cordless tools it often costs far more per hour than the electricity that charges it.
Does it count maintenance, repairs or resale value?
No. It compares purchase price and electricity only. If one model needs filters, belts or a service plan, add that to its price before comparing.