Is battery backup worth it?

Two questions decide this, and neither is about the battery. The first is how much an outage actually costs you. The second is whether your utility offers a time-of-use rate you would be willing to switch to. Answer those and the rest is arithmetic.

The short answer

On a standard flat rate, whole home battery backup will not meaningfully lower your bill. You are buying resilience, and it should be judged on that alone. On a time-of-use rate, the same hardware becomes a machine that lowers your bill every month, and the backup capability comes along with it.

That is why a generic savings figure is worth nothing. The same system in two houses on two rate plans produces completely different outcomes.

Question one: what does an outage cost you?

This is not only about comfort. Count the things that carry an actual price:

• A freezer and fridge full of food, replaced once or twice a year
• Days of work missed because there is no power and no internet
• A flooded basement when the sump pump stops
• A hotel stay when the house gets too hot or too cold to stay in
• Medical equipment that someone in the house depends on

For some households that adds to a few hundred dollars a year of nuisance. For others — anyone running a CPAP, anyone with a flood-prone basement, anyone working from home — a single bad outage justifies a large part of the purchase on its own.

Question two: does your utility offer a time-of-use rate?

This is the lever that turns battery backup from insurance into an investment. On a time-of-use plan, electricity costs more during a defined peak window and less the rest of the day. A battery charges when power is cheap and runs your house through the expensive hours, so you buy very little at the high rate.

In South Carolina that means moving from Dominion's standard Rate 8 to Rate 7. How that actually works →

If your utility has no equivalent plan, the savings side of the case largely disappears and you are back to judging it purely as backup.

When it is not worth it

Worth saying plainly, because most sites selling batteries will not. Battery backup is a poor purchase if your power is reliable, your utility has no time-of-use option, and nobody in the house depends on electricity for health reasons. In that situation you are spending five figures to solve a problem you do not have.

The analyzer is built to tell you this. If the numbers do not work for your house, it says so rather than producing an encouraging figure.

What payback actually looks like

The calculation is simple once you have your own numbers: take the system cost, subtract incentives, and divide by what it saves you monthly.

What makes published payback figures unreliable is that every input varies — the spread between peak and off-peak pricing, how much electricity you use during the peak window, the size of system you buy, and whether you add solar. Two neighbours can reach very different answers. Here is the full breakdown on Rate 7, worked with published bills.

Incentives matter here too. The 2026 tax credit changes the net cost, and it applies to battery storage in a way it does not to a generator.

How to get your own answer

Everything above is the framework. The number is specific to your house, your usage, and your rate plan. Run your bill through the analyzer and it works through your backup time, your savings from a rate switch, and a right-sized system with pricing — including telling you when it is not worth doing.