For home batteries, the Tesla Powerwall 2 is the best bang for your buck—or at least the most kilowatt-hours for your cash.
The Powerwall costs less per kWh of storage than almost every other popular battery quoted on the EnergySage Marketplace. The total cost is similar to its closest competitors, but the Powerwall holds about 30% more energy. That extra capacity can keep essential appliances running longer during a blackout, and helps you squeeze extra savings out of solar panels in places like California and Hawaii (where you now need a battery to make solar worth it).
Energy storage isn’t the only feature that matters in a home battery, though, and the Tesla’s other key specs are just OK. The Powerwall can’t power as many appliances at the same time as other popular models. Other brands make it easier to customize a backup system, especially if you want the flexibility to get through multi-day blackouts. And some people just can't stand the Tesla brand, for reasons that have nothing to do with their products' performance or specifications.
Even so, the Powerwall’s low cost per kWh is a huge upside. Not everyone needs a home battery, but if you do, the Tesla Powerwall is well worth a look for the price alone.
Tesla currently offers two Powerwall models: the Tesla Powerwall (also known as the Tesla Powerwall 2) and the Powerwall+. The main difference is that the Powerwall+ includes an integrated inverter and system controller. Most certified installers currently install the Tesla Powerwall+, but you might still be able to install a Powerwall.
The upgraded Powerwall 3 is coming sometime in 2024, though we're not sure yet if Tesla plans to discontinue one or both of the older models reviewed here.
For home batteries, the two most important specs to watch are:
Continuous maximum power output: How much stuff a battery can run all at the same time, measured in kilowatts (kW).
Usable capacity: How long a battery can run your stuff, measured in kilowatt hours (kWh).
When you divide the capacity by the maximum output, it tells you the minimum amount of time a battery can keep your home running on its own. With the Powerwall, that’s a little more or a little less than 2 hours, depending on the variant. The real-world backup window is probably longer than that, because you generally won’t draw the maximum amount of power from your battery.
More on these specs and others in our buyer's guide to home batteries.
What comes with the Powerwall?
Indoor/outdoor rated case, so you can install it wherever it makes the most sense (as long as it aligns with local safety codes and Tesla's own installation requirements).
Backup Gateway, a controller that allows you to select critical circuits and automatically switches to battery power at the first sign of a grid outage.
Powerwall+ comes with built-in inverters for solar and storage (though it's not a hybrid inverter).
Even though the Powerwall 2 has been out since 2016, it remains wildly popular. "I'd say the Powerwall is still the industry standard," says Spencer Fields, head of research at EnergySage. More than 166,000 quotes for home batteries were uploaded to the EnergySage Marketplace in the first half of 2023, and about 25% of them included the Powerwall—good for the second most-quoted battery, behind only Enphase.
What’s the key to its continued success? The brand name probably helps, and installers tell us that they like working with it. More importantly, though, it’s well rounded and reasonably priced.
The low price is hard to beat
Plenty of batteries can effectively provide a few hours of backup power, and help you squeeze extra value out of your solar panels in some circ*mstances. The Powerwall just costs less than almost all of them.
On the EnergySage Marketplace, the typical quoted all-in cost of installation for a single Powerwall with everything included (battery, inverter, backup switch and load manager, permitting, and labor) was about $1,183 per kWh of capacity during the first half of 2023. That's 15% less than the average on the EnergySage Marketplace and about 20% less than the other most popular battery brand, Enphase. Those prices are before a 30% federal tax credit and any state, local, or utility incentives you might qualify for.
At roughly $16,000 all-in, the Powerwall's total cost of installation isn't the lowest we regularly see on the EnergySage Marketplace. Plenty of other popular brands go in for $15,000 total. The Powerwall holds more electricity than those batteries, though (13.5 kWh vs. 10 kWh, typically), and that extra capacity often helps owners offset enough of their nighttime, non-solar energy use to make up the cost difference. The extra backup energy can be useful, too.
The features are adequate for most homes
The Powerwall's most important specs and features are average for what you can expect from a battery in 2023. In other words, it's nothing special, but more than enough to handle what most people need from a battery. They include:
Backing up critical appliances and gadgets during a short power outage. Fridge, lights, water pump, WiFi, TV—that sort of thing, for at least a few hours. Statistically speaking, power outages rarely last longer than that, so the Powerwall should have you covered. This setup might even save you money over time vs. a gas generator. There are plenty of exceptions, of course, and if you want to run an air conditioner or heat pump during an outage, things can get more complicated. But a Powerwall can help you stay safe, fed, entertained, and connected to the outside world.
Making solar panels worth it when the utility company won't give you a fair deal. Some utility companies only allow you to tie your solar panels to the grid when you agree to sell them unused power at a deep discount. This practice typically wipes out the financial advantages of going solar—but a battery like the Powerwall tilts the math back in your favor. It hoards energy from your panels during the day, then powers your home once the sun starts to set (typically in the early evening when the demand on the electrical grid is at its highest). Over time, you should save enough on your electric bills to cover the cost of the battery and then some. You might even be able to use a battery to squeeze some extra cash out of your utility company if they have time-of-use rate plans or virtual power plant programs.
Owners seem to like it
At least as far as we can tell. The Tesla brand earns a 4.5 out of 5 star rating on the EnergySage Marketplace, based on more than 570 reviews. Most of those reviews are about Tesla installers rather than the equipment itself. But since you would be getting a Powerwall installed by a certified Tesla pro, that rating bodes well for your installation experience.
Detailed user reviews about the Powerwall are hard to come by. That's probably because after you install a Powerwall, it's more about what you don't notice. When the grid goes out, the Powerwall should kick on before you see the lights flicker. You might notice a lower electric bill if you're stuck with one of those solar billing plans that favors the utilities. The battery itself? It's just a box, sitting somewhere inconspicuous.
Influential YouTuber Matt Ferrell posted a few videos about his experience with his Powerwall. His only specific feedback about the product (rather than battery storage in general) is that he likes the Tesla app because it has a clean interface and makes it easy to choose a preferred charging behavior for your situation.
It's not the best system for lengthy blackouts
If multi-day power outages are a regular part of life in your neck of the woods, you'll most likely need a higher continuous output (measured in kW) and more capacity (measured in kWh) than a single Powerwall can offer, especially if you want to be able to run an air conditioner or a heat pump.
You can always install multiple Powerwalls. According to Tesla, you can string together up to 10 Powerwall 2 units in a series, which is enough power to keep most homes running for a couple of days, even without solar power refilling the system.
Powerwalls can also be installed in parallel—essentially working like two separate backup systems—to double the power output. The Powerwall 3, coming in 2024, will also have a higher maximum power output.
That said, other brands like Enphase and Homegrid offer more flexibility for scaling up your system, now or in the future, and have some of the industry's highest power outputs. "Storage isn't one size fits all," Fields says, "and the building blocks for the other brands are better." Homegrid in particular makes it easier to add both capacity (kWh) and power output (kW). Alternatively, you could look into a generator-integrated system, like Generac's PWRCell battery.
The app is too basic for some owners' preferences
Though some owners like the Powerwall app's clean interface and relative simplicity, others find it lacks the control they would like. "If you like self-driving cars, you will love it. Set and forget for 25 years. If you want control, it falls short by a mile," wrote one user on the EnergySage Marketplace.
One Redditor pointed out that the app has no setting that dynamically switches between charging from solar panels or the grid. Few people will need this setting since almost nobody is on a residential electric rate plan with prices that change in real time. (You can set up the app to switch behaviors at certain times of day to take advantage of time-of-use plans.) Another Redditor who chose Enphase over Tesla points out: "Enphase is easier to get a bit creative with, has programmable relay outputs which can be used to load shed or keep stuff online when there's no grid but plenty of solar, etc." Several other battery brands offer controls more like Enphase's.
The Powerwall also has a feature called StormWatch that claims to prioritize charging the battery in anticipation of significant weather events (just in case you need backup power). Reviews are mixed. Some owners claim it works no problem, others claim it never works, or only works intermittently.
Tesla's inverter isn't the best choice for every roof
If you have a roof with more than a few juts, angles, and shaded areas, make sure your installer pairs the Powerwall with an inverter system suited to those conditions, like Enphase or SolarEdge. The Powerwall battery pack itself doesn't have anything to do with this. But most installers default to a Powerwall variant called the Powerwall+, which is a Powerwall 2 with built-in, Tesla-brand inverters. Installers like the Powerwall+ because it saves time and hassle when they’re setting up combined solar and storage systems.
But Tesla's inverter doesn't optimize the power output of each solar panel like the leading brands do. The most popular inverters manage the power at an individual, panel-by-panel level. The Tesla inverter groups the panels into just four zones. If one panel in that zone gets shaded and the power output drops, every other panel in that zone also drops to that lower power level, even if they're getting direct, unimpeded sunshine.
If shifting shade patterns aren't an issue on your roof, you'll have no problem with the Powerwall+. Even if some solar panels will get some shade, a good installer can probably design around it. But the more nuance you have in your roof, the stronger the case for picking a non-Tesla inverter, and that means skipping the Powerwall+. The regular Powerwall paired with a different inverter could work fine.
After years of crystal ball-gazing by the clean-technology media, Tesla officially announced that their next-generation battery, the Powerwall 3, is coming in 2024. (Limited installations may have already begun, according to Electrek.) Its specs will align more closely with today's market-leading batteries.
The main upgrade is that the continuous output has jumped to 11.5 kW, supplying about twice as much power at once as the basic Powerwall 2. You should be able to keep your entire house running with that level of output, even if that includes an AC or a heat pump and a bunch of extra appliances and gadgets simultaneously. Height-wise, the case is significantly shorter than the existing Powerwall+ so that it can fit into more spaces.
This article was originally published on August 7, 2022, and has been updated.
