The complete buyer’s guide to home backup batteries in 2024

When you picture a battery, the first thing to come to mind is probably the disposable batteries you put in everyday appliances like your TV remote—but did you know you can power your entire house with (much larger) batteries?

Whether you frequently experience outages, are paying exorbitant electric bills, or simply want more energy independence, batteries can be a great investment for your home. You don't need a home solar panel system to reap the benefits of batteries, but you'll get the most out of your system when you pair them together, especially if your utility doesn't pay you a lot for the excess electricity your solar panels generate and send to the grid. 

We'll explain how to decide if backup batteries are right for you and, if so, how to get a battery system that fits your needs at the best price.

Batteries work by storing energy produced now for use later. Instead of having to produce electricity at the exact time when you need it, batteries allow you to generate electricity at any time, providing flexibility for how you meet your demand with supply. Storing energy offers many benefits, from financial savings to backup power in a grid outage.

For most battery systems, there's a limit to how much energy you can store in one system—to store more, you need additional batteries. Additionally, in most cases, batteries can't store electricity indefinitely: Even if you don't pull electricity from your battery, it will still lose its charge over time.

We'll focus on the benefits of home backup batteries throughout this guide, but it's also important to understand why batteries are increasing in importance at a much larger scale: 

You don't need solar to install a home battery, but remember that batteries only store energy—they don't produce it. To truly increase your grid independence and your electric bill savings, you'll want to pair your battery system with a solar power system. Here's how it works: 

1. Your solar panels generate direct current (DC) electricity from the sun's energy.

2. The DC solar energy flows through an inverter (or multiple inverters), which converts it to alternating current (AC) electricity, the type of electricity that most home appliances use.

3. You run your home on this AC electricity. 

4. Any extra electricity you don't consume charges your batteries (either pre- or post-inversion, depending upon the system you install – more on this below).

5. When the sun goes down or the power goes out, the energy stored in your batteries powers your home.

Most batteries last about 10-15 years, meaning you'll have plenty of time to break even on your investment. While many homeowners can benefit from installing a battery system, they're not right for everyone. Here are a few questions to answer when deciding if you should add a battery to your home: 

According to our latest Solar & Storage Marketplace Report, the median battery cost on EnergySage is $1,339/kWh of stored energy. This means that a 10 kWh battery will likely cost over $13,000. This price tag is high, but if you've determined that a battery is right for you based on your answers to the questions we outlined above, it will pay off over time. 

For example, if you're a California homeowner looking to go solar, your utility will put you on a particular TOU rate plan, and you won't have access to net metering, making you a great fit for a home battery. By installing a solar-plus-storage system instead of a solar-only system in California, you could save $21,600 to $43,900 more over 20 years and, despite higher upfront costs, break even on your investment 1-2 years sooner.

Keep in mind, if you live somewhere with net metering and a flat, non-time varying electricity rate, the only financial savings from installing energy storage come from avoiding outages or receiving any available state incentives. In those instances, you won't see any more bill savings from adding a battery to your solar panel system. 

Learn more about how much batteries cost.

If you want to install a home battery but are overwhelmed by the cost, don't worry: Plenty of incentives are available that will significantly lower the price. Depending on where you live, you could break even on your storage investment in less than a year! Here are some of the top battery incentives that will either reduce your upfront cost or increase your long-term savings:

Your eligibility for many of these battery incentives depends on how you pay for your battery. If you finance it with a lease, you'll miss out on some of the best incentives available, including the ITC and state rebates. Here are the three main ways to pay for your battery system: 

1. Cash: Paying for your battery system with cash is the best way to maximize your long-term savings, but many homeowners don't have the money required to purchase their battery system upfront, especially if it's paired with solar.

2. Loan: Many people choose to finance their battery systems with a loan: You'll still qualify for incentives, and you could start saving on day one if your monthly loan payments are less than your previous electric bills. If you're buying a new solar-plus-storage system, adding the price of a battery to your solar loan will increase your monthly bills slightly.

3. Lease: It may be challenging to find a lease for a standalone battery system, but adding a battery to your solar lease is relatively easy. However, with a lease, you won't own your system, so you won't qualify for some of the best solar incentives, as explained above. That said, if you're worried about controlling your battery to optimize savings under complex utility rates or reduced net metering, financing a battery with a lease is a good way to lock in your monthly payments without needing to make battery dispatch decisions on your own.

Learn more about how to pay for your battery system.

Batteries aren't the only form of home energy storage. If you've experienced a power outage in the past, you may have already invested in a generator. There are two primary reasons homeowners have historically opted for backup generators over batteries: They cost less upfront than home backup batteries, and they're easier to find and set up on your own—with some, you may not need any help from an electrician.

However, home backup batteries are becoming an increasingly popular choice over home generators, offering many of the same backup power functions as conventional generators but without the need for refueling. While they're more expensive upfront and require an electrician to install, when paired with solar panels, you can "refuel" them for free with the sun's energy. They're also much quieter than generators and don't come with emissions-related health concerns. 

Home batteries vs. generators

The best battery for your neighbor may not be the best battery for you, but some key factors can help you differentiate between the various brands and models. Here are some questions to answer when selecting the right battery for your home:

What's the battery chemistry?

Your battery's chemistry refers to the primary compound used to store energy. Today, most home batteries use lithium-ion chemistries due to their high power density, though you may still find portable or car lead-acid batteries. Three types of lithium-ion battery chemistries are popular in home batteries:

1. Nickel manganese cobalt oxide (NMC): NMC is today's most common home battery chemistry. Most homeowners choose NMC batteries for their relatively low price point and high energy density. However, they tend to have shorter lifespans and are less stable than other lithium batteries, making them slightly more prone to safety issues.  

2. Lithium iron phosphate (LFP): LFP batteries are quickly gaining on NMC batteries in popularity due to their relatively long lifespans, stability, and moderate price point. However, they often have lower energy densities than NMC batteries and tend to cost more.

3. Lithium titanate (LTO): LTO batteries are new to the home battery market. They cost more upfront than NMC and LFP batteries and have lower energy densities but offer the longest lifespans, fastest charge times, and the highest level of safety because they're not flammable.

Types of battery chemistries compared

Do you already have solar?

Batteries can be either AC- or DC-coupled when paired with solar, and some brands, like LG Chem, offer both solutions for their battery models. Here's how each type of system works:

• AC-coupled: If you already have a solar installation, in most cases, you'll need to choose an AC-coupled battery. With an AC-coupled solar-plus-storage system, your solar panels produce DC electricity, which your solar inverter converts to usable AC electricity. Then, your storage inverter converts the electricity you don't use back to DC electricity for storage in your battery. When you want to pull electricity from your battery, it's converted back to AC electricity. If you are pairing storage with a solar panel system that uses microinverters, you will have to install an AC-coupled solution because the microinverters change the DC to AC electricity right at each individual solar panel.

• DC-coupled: DC-coupled batteries provide more efficiency if you don't already have solar and are looking to install a solar-plus-storage system or a storage-only system. With a DC-coupled solar-plus-storage system, your solar panels produce DC electricity, which flows directly through your battery. Your inverter then converts any electricity you don't store one time so you can use it or send it to the grid. You may not be able to participate in some battery incentive programs with DC-coupled systems because your utility can't control the flow of electricity in and out of the battery.

AC- vs. DC-coupled batteries

Does the battery come with an inverter?

Like solar panels, batteries need an inverter to convert their stored DC electricity into usable AC electricity. Different types of inverters exist, depending on whether your battery system is AC- or DC-coupled. DC-coupled batteries often come with an integrated hybrid inverter for both solar and storage. AC-coupled batteries sometimes come with an integrated storage inverter, which only works with storage, meaning you'll need a separate solar inverter. Some batteries don't come with an inverter, so you must pair it with a separate, third-party inverter. 

You may be able to save on equipment costs with a hybrid inverter, but you could have higher installation costs if retrofitting to an existing solar system, and you could miss out on some incentives, as we previously described. 

How much storage capacity and power do you need?

There are two ways to measure the output you'll get from your battery: usable capacity and power rating. Usable capacity is measured in kWh and describes the maximum amount of electricity your battery can store on a full charge. The higher the usable capacity, the longer your battery's runtime. When comparing the usable capacity of different batteries, you'll also want to consider how many batteries you can stack in parallel; even if the usable capacity of one battery is low, if you can connect multiple batteries to one inverter, it may allow you to customize your system to meet your energy needs better.

Your battery will come with two power ratings, both measured in kW. Its peak power rating measures the amount of power your battery can output in a short period. It's important to have a battery with a high peak power rating if you need it to run appliances that require a lot of energy to start, like an air conditioner or a sump pump. Your battery's continuous power rating measures the amount of power your battery can output consistently. The higher its continuous power rating, the more appliances you can run at once.

Ultimately, the amount of capacity and battery backup power you need depends on how much of your house you plan to power with your battery—and for how long. 

How well does the battery perform?

Two primary metrics differentiate batteries in terms of performance. Depth of discharge (DoD) indicates the percentage of the battery that can be discharged relative to its overall capacity. In other words, it's the amount of your battery's capacity you can use in one cycle for optimal battery performance: The higher the DoD, the more you'll get out of your battery.

Roundtrip efficiency measures the electrical losses involved with charging and discharging a battery. Batteries with higher roundtrip efficiencies better convert incoming electricity into stored electricity and back to usable electricity; they're considered higher-performance batteries.

How long will the battery last?

Every time you charge and discharge your battery, it slightly reduces its ability to hold a full charge. A battery system is a big investment, so you'll want to ensure it lasts. The best way to feel confident that your battery will continue working efficiently is to choose one with a strong warranty. Battery warranties include many different components and clauses, which all impact the assurance you can feel when choosing a long-lasting battery. 

Your battery's warranty period is measured in years and covers the integrity and output of your system–typically, battery companies offer 10-year warranties. Most battery warranties also include an end-of-warranty capacity guarantee, which states that by the end of the warranty period, the battery will still maintain a certain percentage of its original usable capacity. Batteries also often come with a cycles clause (a specified number of times you can drain and charge your battery under warranty) and/or a throughput clause (the total amount of energy the manufacturer expects the battery to deliver throughout its lifetime). Similar to how many car warranties come with a time and/or mileage component (i.e., ten years, 100,000 miles), if you hit your warranted cycle life or throughput before your battery reaches the end of its warranty period, it could end your warranty term. 

You'll also want to look at other warranty information, like if labor and shipping costs are covered for repairs and replacements; batteries are considered hazardous waste, which means that these costs can be extremely high in some cases if you need to send the battery back to the manufacturer for diagnostics.

Is the battery compatible with energy management systems?

Energy or load management systems enable you to both monitor and control your energy consumption, typically at the circuit level. In most cases, if you're installing a battery, you'll need to install a critical load panel, which protects your appliances and battery from unintended electrical failures and enables you to power only your most essential devices during power outages.

Energy management systems replace the need for a critical load panel by providing real-time flexibility, allowing you to turn circuits on and off remotely. They can replace your main electrical panel, serve as a sub-electrical panel (similar to a critical loan panel), or be installed along individual circuit lines for a more modular approach. Most importantly, these systems allow you to get more out of your battery during power outages by only powering the most important loads at a given time. One of the most prominent energy management system brands, Span, claims that their smart home panel provides 40% longer backup than battery-only systems. 

Some battery companies are now manufacturing their own energy management systems, while others are compatible with third-party systems like Span and Lumin. Not all batteries are compatible with all energy management systems, so make sure to pick a battery compatible with the energy management system you prefer. 

How much does the battery cost?

You'll want to get the most bang for your buck when purchasing a home battery. Battery cost comes down to two key factors: the equipment and installation time. Some batteries are more expensive due to factors like their chemistry or supply chain strength, while others may be bulky and large and, therefore, more difficult (and expensive) to install. 

Thousands of homeowners request battery quotes through our Marketplace every year, providing us with unparalleled insight into the cost of different battery brands. Based on our latest Solar & Storage Marketplace Report, there's an extensive range in battery prices: HomeGrid offers the lowest cost batteries at $480/kWh, likely in large part due to their flexible configuration, which makes them easy to transport and quickly install, while Sonnen offers the highest cost batteries at $1,570/kWh, likely due to their extremely strong warranty. The most quoted battery company on the EnergySage Marketplace is Enphase, which surprisingly is the second most expensive battery brand at $1,490/kWh. 

What are the best home batteries?

While there are many great battery companies, a few stand out above the rest. Depending on what you're looking for in a battery system, HomeGrid, Villara Energy Systems, Sonnen, and SolarEdge offer some of the best solar batteries today:

Best backup batteries compared

If you're ready to install a home battery system, we're here to help. Here's how to get started without feeling overwhelmed: