Free tool

Generator vs home battery 10 year cost calculator

With typical US prices, a standby generator usually costs less over 10 years than a home battery, because it is cheaper upfront and fuel for a few outages a year is modest. Change any assumption below to see how your quotes, outage hours and fuel prices change the answer.

By The WattFort TeamUpdated Runs in your browser, nothing is sent anywhere

Enter your own local prices for accuracy. Your choice is remembered on this device.

Rates updated 13 Nov 2026

Your 10 year comparison

Defaults are typical US figures. Change any of them to match your quotes.

Assumptions

Your result

Suburban house with solar panels on the roof

How the calculator works

  • Upfront = installed price × (1 minus rebate).
  • Generator each year = (outage hours + exercise hours × exercise fuel share) × fuel use per hour × fuel price, plus servicing.
  • Battery each year = outage hours × average load ÷ round trip efficiency × electricity price, plus upkeep. That is the grid electricity needed to refill what you used.
  • Running totals are added for each year, plus a battery replacement in the year you choose.

It ignores financing, inflation, resale value and any daily savings from solar or tariffs, so treat it as a like for like backup comparison. For what each option can actually power, see our generator size calculator and power station runtime calculator.

Frequently asked questions

Is a home battery cheaper than a generator over 10 years?

Usually not on cost alone. Our default figures use the midpoints of the price ranges Duke Energy quotes and 11 outage hours a year, the US average in 2024. With those figures, the standby generator stays cheaper over 10 years because its upfront price is lower and fuel for occasional outages is modest. A battery can close the gap with incentives, a lower installed quote, or savings from solar or time of use tariffs, which this tool does not count.

What costs does the calculator include?

Upfront purchase and installation less any rebate, fuel for outages and weekly exercise runs, yearly generator servicing, grid electricity to recharge the battery after outages, battery upkeep, and an optional battery replacement. Every figure is editable.

Why does the generator use fuel when there is no outage?

Most standby generators run a short automatic exercise cycle, often weekly, to keep the engine healthy. We assume 13 hours a year at half the normal fuel rate. Check your manual and change the figure if yours differs.

Does this include savings from solar or time of use tariffs?

No. It compares backup costs only. If you pair a battery with solar or use it to shift grid use to cheaper hours, it can save money every day, which a generator cannot do. Our guide on whether a home battery is worth it without solar covers that.

What if I have many more outages than average?

Raise the outage hours. Longer outages add fuel cost to the generator while the battery cost barely moves. A battery only lasts as long as its stored energy unless it has solar, though, so check it can actually cover your outages.

Which currency does it use?

You can show every amount in US dollars, pounds, euros, Canadian dollars, Australian dollars, Indian rupees or Pakistani rupees using the currency selector at the top of the calculator. Amounts are converted from US dollars at live exchange rates loaded when you open the page and refreshed every few hours, with saved rates used if you are offline. Rates come from ExchangeRate-API (open.er-api.com), and the backup rates built into this page are from 13 November 2026. Treat them as a guide only and enter your own local prices for accuracy. Amounts you type are converted back to US dollars for the maths. The defaults are typical US figures from US sources.

Sources

Figures are typical values for planning, not a substitute for your appliance labels or an electrician's load calculation.

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