Tesla Powerwall: What you need to know before buying one

Blog Post by SunSource Homes

In 2015, energy icon Elon Musk shared his latest creation with the world: the Tesla Powerwall.

An innovative home battery, the Tesla Powerwall sparked joy for eco-conscious people around the globe.

Many people want to get their hands on one but what exactly sets a Tesla Powerwall apart from any other home battery? How does it work? Should you get a Tesla Powerwall for your home or is it just a bunch of hype?

tesla powerwall

What is the Tesla Powerwall?

According to Tesla, a Powerwall is simply “a home battery.” The first Powerwall launched in spring 2015; the second came in fall 2016 and had twice the capacity of the original. Both versions of the Powerwall outperform most home energy batteries in terms of storage capacity.

How the Tesla Powerwall works

Typically, when a homeowner adds solar panels to their home, they remain connected to the grid. Whenever their solar panels overproduce, they send that energy back into the grid. If their home uses more energy than their solar panels produce, it automatically switches to the grid for power.

When you install a home battery, your battery will store the excess energy rather than sending it back into the grid. If you need more energy than your solar panels are producing, your battery will take over. Your battery will also act as a backup generator in the event that your solar panels go offline.

tesla powerwall how it works
Graphic Courtesy of Energy Sage

This process will happen over the course of an entire day. You’ll produce the most when the sun is high in the sky, around noon. The excess energy you generate will then be stored in your Tesla Powerwall. When the sun goes down and your solar panels’ production decreases, you’ll use that electricity you stored during the day.


But even if you don’t have a solar system, the Powerwall can still be useful.  According to Tesla, the “Powerwall detects grid outages and automatically becomes your home’s main energy source.” If you want to use the battery daily without a solar system, you will have to manually switch your energy source from the grid to your battery.

Tesla is working to make this process automatic but has not given a date for when this feature will be available for homes without solar panels.

Does this mean I can go off the grid?

While the battery will help you take charge of your electricity bill, this doesn’t guarantee your ability to completely disconnect from your utility company. A single battery will only provide you backup for a few hours. This won’t cover you if you have a cloudy day, and especially not several days – or weeks- of inclement weather.

It is possible, but going off the grid is still a feat that would require many batteries which means it would be expensive.

How much does the Tesla Powerwall cost?

A Tesla Powerwall 2.0 is currently listed for $6,700. The hardware needed to support the battery is approximately $1,100. You’ll also need to factor in the costs for any needed electrical upgrades, taxes, permit fees, and connection charges. Then, add in the price for paying your installer. This varies from company to company.

When shopping around, always pick an installer that

Unfortunately, there are many companies who are taking advantage of buyers. So it is important to check reviews of other customers and check with Tesla yourself to make sure the company is indeed certified. (SunSource is one of the few installers that can claim all three of these traits.)

Remember that these fees do not take into account financial incentives. If you chose to install the Powerwall as part of a solar system, you can claim the installation costs when you process your federal solar tax credit.


How long will a Tesla Powerwall last?

tesla powerwall installation

Your Powerwall comes with a 10-year warranty that is unlimited, meaning there is nothing that voids your warranty. The warranty assumes you are using your battery daily and guarantees to retain at least 70 percent of its capacity to charge for 10 years.

Just like all rechargeable batteries, the Tesla Powerwall loses some of its ability to hold a charge over time. That’s why Tesla only guarantees the deterioration won’t go pass a 30 percent loss of storage.

How to purchase a Tesla Powerwall

You can purchase a Tesla Powerwall directly from Tesla or through a certified installer, like SunSource Homes.

If you want to purchase one from Tesla directly, visit the Tesla website and fill out their form for requesting a Powerwall. The form calculates how many batteries you need based on the square footage you select and your estimated daily use of kWh. After you complete your selection, the form will show you the final price, including hardware for installation. Please note that the form does not add in the calculations for labor and installation. That is information you will have to get from your solar installer.

tesla powerwall how to purchase
The beginning of the form on Tesla’s website

Whenever batteries are on back-order, Tesla allows you to reserve your Powerwalls with a $500 down payment.

Don’t want to wait? Check out the sonnenBatterie from one of the leaders in the energy industry.

If you want to purchase batteries from an installer, find a company that is a certified installer and tell them you are interested in a Tesla Powerwall. They will handle all the paperwork for you.

If you are interested in solar panels as well, it would be best to chose a company that is a reputable solar installer that carries a certification for installing Tesla Powerwalls. This way, you will cut down on installation costs as you’ll pay one company for two jobs rather than two separate companies.

Whichever path you chose, Tesla only sends Powerwalls to the homeowner, not to the company. You should receive your Powerwall at your home and then have a certified installer come set up your battery.

Is going solar with a battery backup a good choice for your home? Get a free, no obligation quote and find out now. 

If you have more questions about the Tesla Powerwall please contact us.
Interested in learning more about solar systems? Check out our Solar 101 series for answers to common solar questions.