Payback Math: How Many Outages Before Backup Power Pays For Itself?

Number 1: How often does your power actually go out?

Not how often you worry about it. How often it happened.

Count the outages over four hours long since 2020. Six years. If you cannot remember, that itself is data — it means the answer is close to zero.

Divide by six. That is your outages per year. For most American suburbs it lands between 0.3 and 2. In parts of Texas, Louisiana, Michigan and rural New England it is meaningfully higher.

Your utility publishes reliability statistics, and many outage maps keep a history. If you want a real number rather than a memory, that is where to find it.

Number 2: What does one outage cost you?

Add up what you actually lose in a typical event:

For a short outage where you keep the doors shut, the honest answer is often under $50. For a two-day outage in summer with a full freezer, it is $400–$900.

Insurance usually does not rescue you here, because the common exclusion is off-premises power failure and the deductible eats what is left. Details here.

Number 3: What does the equipment cost?

Round numbers for the tiers on this site:

Add a panel ($200–$500) if you want multi-day capability.

Number 4: How long does it last?

A LiFePO4 unit rated for 3,000+ cycles, used a handful of times a year and stored properly, will last well past ten years. Something else usually fails first — see How Long Do Solar Generators Actually Last?

Use 10 years as a planning figure. It is conservative for the cells and realistic for the electronics.

Now do the sum

(Outages per year) × (cost per outage) × 10 years vs. equipment cost

Three worked examples:

The suburban house that rarely loses power. 0.4 outages/year × $150 × 10 = $600 avoided against a $700 unit. Roughly break-even after a decade. The math says this is a comfort purchase, not an investment. That is a fine reason to buy — just know which one you are making.

The Texas or Michigan household. 2 outages/year × $450 × 10 = $9,000 avoided against a $900 unit. Ten times over. This is not close, and if you are in this group and have not bought anything, you are choosing to lose money.

The rural well-water household. 1.5 outages/year × $700 (food, plus no water at all, plus a hotel) × 10 = $10,500 against a $2,500 large unit and pump setup. Clearly worth it — and the water is why, not the food. See Can You Run a Well Pump on a Solar Generator?

The things the sum leaves out

Money is not the only axis, and pretending otherwise would be dishonest in both directions.

Buy regardless of the math if: someone in the house depends on powered medical equipment, or refrigerated medication, or you have an infant, or you are on a well, or you are elderly and cannot easily leave in a heat event. Those are safety purchases and the payback calculation does not apply. It never did.

Do not buy if: the answer above came out negative and none of those apply. Spend the money on a chest freezer full of frozen water jugs, a good cooler, headlamps and a $50 hand-crank radio. That kit costs a fifth as much and covers the four-hour outage that is the only kind you get.

We would rather write that sentence than sell you a battery.

The cheapest version that works

If the math is marginal and you want something:

• $40 — headlamps, a battery radio, a fridge thermometer, frozen water jugs
• $250 — a 300Wh unit for phones, router and a fan
• Stop there until you have had an outage that made you wish for more

That is the honest ladder. Most people should be on the second rung, and the industry would prefer you started on the fourth.

The short version

• Count real outages since 2020 and divide by six. Memory is not data; the number usually surprises people.
• One short outage costs under $50. A two-day summer outage costs $400–$900.
• Multiply, compare to equipment cost over ten years, and read the result honestly.
• Buy regardless of the math for medical needs, infants, well water, or if leaving is hard.
• If the math says no, buy the $40 kit and a cooler instead.