Are Home Batteries Actually Worth It?
Depends on what you're trying to solve.
If you lose power once every 5 years for a few hours? Probably not worth $10,000-15,000. But if you're in Texas during winter storms, California during wildfire season, or anywhere with regular outages? The math changes fast. And if your utility has time-of-use rates where electricity costs 3x more at peak hours? Batteries can pay for themselves in 7-10 years just by storing cheap power and using it during expensive periods.
How Much Battery Capacity Do You Actually Need?
Real question: What are you trying to keep running? I've helped dozens of homeowners right-size their battery systems, and this is where most people overspend.
A Tesla Powerwall (13.5 kWh) can run a fridge, internet, lights, and some outlets for 24+ hours. Add a heat pump or AC? Maybe 8-12 hours. Try to run everything in your house like normal? 4-6 hours max.
Essential Loads vs. Whole Home
Most people pick "essential loads" backup. That's fridge, freezer, internet, a few lights, phone chargers, garage door, maybe a sump pump.
Whole-home backup sounds great but costs 2-3x more because you need multiple batteries. If you're serious about multi-day outages, you also need solar to recharge during the dayâotherwise you're just delaying the inevitable.
With Solar vs. Without
Battery-only systems give you backup power but don't recharge during outages. Once depleted, you're done.
Battery + solar systems recharge daily, giving you indefinite backup (as long as the sun shines). This is the move if you live somewhere with multi-day outages. But you're looking at $25,000-40,000 total for a properly sized system.
Battery Options - What's Actually Good?
I'll be straight with you: Tesla Powerwall dominates for a reason.
Tesla Powerwall 3
13.5 kWh capacity, $9,000-11,000 installed. Industry standard. Works great with or without solar. Integrated inverter means simpler installation. The app is excellent. Availability can be spotty depending on your area, but if you can get one, it's the default choice.
Enphase IQ Battery 5P
5 kWh per unit, modular design. Great if you already have Enphase microinverters. More expensive per kWh than Powerwall ($3,500-4,500 per 5kWh unit), but the modularity means you can start small and add more later. Good option if you need exactly 10 kWh or 15 kWh and want to avoid oversizing.
LG RESU / Generac PWRcell
Solid alternatives if Powerwall isn't available. Similar pricing, similar performance.
The main difference? Installer preference and local availability. Most solar installers carry one or two brands. If they push hard for a specific battery, it's usually because that's what they stock and know how to installânot because it's objectively better.
Should You Get a Generator Instead of a Battery?
Generators are way cheaper upfront. No question. But in my experience, the ongoing hassle makes batteries worth the premium for most homeowners.
A decent whole-home standby generator costs $5,000-8,000 installed. A portable generator? $500-1,500. But you need to store gasoline (fire hazard, goes bad after 6 months), deal with noise and exhaust, and remember to actually start the thing during an outage. Batteries are silent, automatic, and work inside without carbon monoxide risk.
For occasional short outages, a portable generator makes more sense financially. For frequent outages or if you have solar, batteries are better long-term.
Common Questions I Get
How long do home batteries last?
10-15 years. Most warranties guarantee 70% capacity at year 10. After that, the battery still works but stores less energy. You're not replacing it every 3 years like a car batteryâthis is a long-term investment. Factor in one replacement over 25-30 years if you're pairing with solar.
Can I install a battery myself?
No. These systems connect to your main electrical panel and require permits, inspections, and licensed electricians. Some batteries (like Powerwall) also require certified installers or the warranty is void. Don't try this yourself.
Do batteries work during a blackout if I don't have solar?
Yes, but only until they're depleted. A 13.5 kWh battery running essential loads might last 24-36 hours. Without solar to recharge, once it's empty, you're back to no power. If outages in your area last longer than a day, you need solar or a generator too.
What about tax credits?
If you install a battery with solar, it qualifies for the 30% federal solar tax credit. Battery-only systems? Only if you're charging them from solar at least 75% of the time (which requires having solar already). If you're just charging from the grid for backup, no federal creditâbut check your state. Some states offer separate battery rebates.
Can I add a battery to my existing solar system?
Usually, yes. But it depends on your inverter setup. If you have microinverters (Enphase) or optimizers (SolarEdge), adding a battery is straightforward. If you have a string inverter, you might need to replace it with a hybrid inverter that supports batteries. Your solar installer can assess thisâget a quote before assuming it's plug-and-play.
What size battery do I actually need?
Run the numbers on your essential loads. Fridge (150W), freezer (100W), internet/router (50W), a few LED lights (50W), phone chargers (20W). That's ~370W continuous, or ~9 kWh per day. A 13.5 kWh battery gives you about a day and a half of runtime. If you want 2-3 days without solar, you need 20-30 kWh (two Powerwalls or equivalent). If you have solar, one battery is usually enough because it recharges daily.
Are batteries worth it just for time-of-use arbitrage?
Maybe. It depends on your rate spread.
If you're paying $0.10/kWh overnight and $0.45/kWh at peak (like some California SDG&E customers), you can save $0.35/kWh by storing cheap power and using it during expensive hours. A 13.5 kWh battery cycling daily saves ~$1,700/year. At that rate, payback is 6-8 years. But if your spread is only $0.10/kWh, you're saving $500/year and looking at 20+ year payback. Do the math for your specific utility rates.