Can you really "sell power back to the grid" for profit?
This is the most common myth in home batteries, so let's be straight: in most of the United States you cannot freely sell stored electricity to the grid for profit. What you usually get is net metering — credits for solar you export, typically capped at your own usage. Few utilities pay cash for surplus, and when they do it's at a low wholesale rate, not the retail rate you pay. True "buy low, sell high" arbitrage only pays in a handful of markets with specific export tariffs.
So this calculator deliberately models the two things that actually put money in your pocket:
1. Self-consumption (if you have solar)
Instead of exporting cheap daytime solar and buying expensive power at night, you store your own solar and use it later — avoiding the full retail rate. This is the biggest real saving for most battery owners.
2. Time-of-use arbitrage (with or without solar)
If your utility charges more during peak evening hours, you charge the battery when power is cheap (off-peak or from solar) and discharge during peak — pocketing the price difference, minus about 10% round-trip efficiency loss.
Backup power during outages is a third, real benefit — but it's resilience, not cash, so we don't put a dollar figure on it.
Frequently asked questions
Is a Tesla Powerwall worth it in 2026?
Financially, batteries usually have long payback (often 8–15+ years) unless you have high electricity rates, a big peak/off-peak spread, or frequent outages. Many people buy them primarily for backup power and resilience rather than pure ROI.
Do I get paid to send battery power to the grid?
Rarely at a profitable rate. Most utilities offer net-metering credits capped at your usage, not cash payments at retail rates. Treat grid income as a bonus, not the business case.
Is there still a battery tax credit in 2026?
No federal credit for batteries bought outright — Section 25D expired December 31, 2025. Some states and utilities still offer rebates, and leased systems may pass through value via the surviving commercial credit.
How much battery capacity do I need?
For daily bill-shifting, most homes get value from roughly one usable "cycle" a day — often 10–14 kWh (about one Powerwall). For whole-home backup through a multi-day outage you'd need much more, or you size the battery to cover only essential circuits (fridge, lights, internet, medical devices) to keep cost down.
How long do home batteries last?
Modern lithium (LFP) home batteries are typically warrantied for about 10 years or a set throughput, and often retain 60–70% capacity after that. We use a ~15-year life in the calculator, which is why a payback beyond ~15 years means the battery may not fully pay for itself on savings alone.
Can a home battery power my whole house during an outage?
Sometimes, briefly — but a single battery usually can't run heavy loads (AC, electric heat, EV charging) for long. Most backup setups power selected essential circuits. If whole-home, multi-day resilience is the goal, you'll need more storage or a generator alongside it.
Is a battery worth it without solar?
Only if your utility has time-of-use pricing with a big peak/off-peak gap — you charge cheap off-peak and discharge during expensive peak hours. Without either solar or a large TOU spread, a battery is mainly a backup-power purchase, not a savings one, and our calculator will show that honestly.
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