Is a solar battery worth it?
Bill savings and backup power are two different things. This calculator counts the savings honestly and tells you how many hours of backup you'd get.
Bill savings
$1,287 a year
Pays back in about 11.4 years, inside a typical 10–15 year warranty.
- Value per kWh shifted
- 38.3¢
- 15-year net
- $4,894NPV −$1,287
- Backup for essentials
- 10 hrswithout solar recharging
The honest take
- Backup has real value if outages are common or costly for you (medical equipment, a home office, a sump pump). Put a dollar figure on that yourself; we don't include it.
- A portable power station can cover a fridge and internet for a short outage at a fraction of the cost.
When batteries pay off
Batteries save money when power you'd otherwise export earns much less than power you buy at peak times, such as under California's net billing with time-of-use rates, or when a program pays for battery capacity. Under full retail net metering, the grid already acts like a free battery.
Valuing backup
If outages are common or costly for you, backup has value that bill savings miss. Estimate it yourself, and compare a home battery with a portable power station or generator.
Questions
Do solar batteries pay for themselves?
Often not on bill savings alone. They come closest where export credits are low, peak prices are high, or incentive and virtual power plant programs pay you.
How long will a battery power my house?
A 13.5 kWh battery with a 10% reserve can run about 1.2 kW of essential loads for roughly 10 hours, longer if solar recharges it during the day.