What are the best batteries for whole home backup?

In September 2022, a Category 4 storm named Hurricane Ian hit Florida, leaving about 2.7 million people without power – almost 400,000 people were still powerless five days later. As storms continue to increase in severity and more people are stuck with no lights, no air conditioning, and no Internet, battery backup power is becoming more important and more popular as a home addition. While you might just want to power your most critical appliances during an outage, it's also possible you want the comfort of backing up your entire home. In this article, we'll explain which batteries offer the best solutions for whole-home backup.

Whole home backup refers to a battery storage system that can power your entire home in the event of an outage – for how long depends on factors such as your energy consumption, the size of your system, and if you're pairing your battery with solar panels. Most battery systems provide partial-home backup, meaning you can continue running your most critical loads – like your phone, computer, Internet, refrigerator, and some lights – during an outage, but not your entire home. Check out this article to learn more about how much of your house you can power with a typical battery and for how long.

It's important to keep in mind that batteries are quite expensive: Our latest Marketplace data shows the median battery cost at about $1,300 per kilowatt-hour (kWh). So, you should expect a typical 10 kWh battery for partial-home backup to cost about $13,000, while a whole-home backup system will likely cost at least $40,000.

Let's say you experience power outages often and are tired of either having no electricity at all or having to pick and choose which devices you're able to back up with a small battery or generator – you're a great candidate for a whole home backup system. Here are some of the factors you'll want to consider when assessing different battery systems:

Battery capacity and scalability

The most important factor when choosing a battery system for whole home backup is the size of the system. You can determine the system size based on the capacity of each individual battery and the number of batteries stacked together in the system. Some battery companies offer large individual batteries, while others allow you to stack multiple small batteries in tandem to create a large system size.

So, what's the battery capacity you'll need for whole-home backup? According to the Energy Information Agency (EIA), the average American home uses about 30 kWh of electricity each day – probably closer to 25 kWh in the winter and 35 kWh in the summer. This means that if you want to power your home for a full day, you'll need a battery system that's at least 30 kWh. If you want to run your house for days on end, you'll want to also install solar panels so you can charge your battery system during the day. But keep in mind that storms often bring rain, snow, and clouds: conditions that definitely aren't ideal for solar. You might want to factor this into your calculations depending on how long power outages (and stormy conditions) typically last near you.

Battery power

Power, expressed in kilowatts (kW), is a measure of how many devices you can power with your battery at the same time. There are two different metrics of power that are important to consider when choosing a battery for whole home backup: peak power and continuous power. Peak power indicates the amount of power your battery can supply over a very short period of time (typically just a few seconds) to turn on very power-hungry appliances, such as a sump pump or your HVAC system.

Continuous power, on the other hand, refers to how much power the battery can continually supply over a sustained period of time. Most devices require much less power to run than to turn on; however, if you're running many devices at once, you could exceed your battery's continuous power supply. Learn more about the differences between peak power and continuous power in this article.

Energy management system compatibility

Energy management systems are devices that provide both monitoring and control of your energy usage. Typically, they either replace your existing electrical panel or attach it to its circuit wires. Energy management systems are smart, and simply using the associated app; you can program them to automatically turn loads on and off to maximize your battery's capacity and power.

What does this look like? Maybe you don't need your air conditioner running at all times throughout the power outage – you can set your energy management system to automatically turn this load on and off at certain times during the day so you have it when you need it and conserve your battery capacity when you don't. Similarly, your energy management system will ensure you aren't powering too many loads at once and exceeding your battery's continuous power output.

As a new technology, options are still quite limited when it comes to energy management systems, and not all systems are compatible with every battery! If you want to install an energy management system to maximize your battery system, be sure to check which batteries it can integrate with.

We curated a list of the best battery options if you want whole home backup – but ultimately, the one that's best for you will depend on your own unique setup.

Blue Planet Energy

Best for: guaranteed long lifespan

• Maximum capacity: 480 kWh

• Peak power: 17 kW

• Continuous power: 8 kW

• Smart panel compatibility: Schneider Electric

Blue Planet Energy is a battery company based in Hawaii. In Hawaii, almost 80 percent of new rooftop installations include a battery, many of which are off-grid because Hawaii's electricity cost is the highest in the nation. So, it's no surprise that Blue Planet Energy made our list of top batteries for whole home backup! Blue Planet Energy batteries offer high capacity and power and come with one of the best warranties in the industry: they guarantee that their batteries will last 15 years (or 8,000 cycles, whichever comes first) and will retain 74 percent of their initial capacity at year 15.

While Blue Planet Energy batteries don't have any specific energy management system integrations, like most battery systems, they work with Schneider Electric's Square D Energy Center.

Enphase

Best for: solar energy systems with microinverters

• Maximum capacity: 40.32 kWh

• Peak power: 5.76 kW

• Continuous power: 3.84 kW

• Smart panel compatibility: Lumin

If you've been looking at solar energy systems or batteries, you've probably come across Enphase during your research. They're best known for their microinverters, which convert the electricity generated by each solar panel into usable electricity. Enphase offers both the most popular inverters and the most popular batteries on the EnergySage Marketplace.

Enphase's Full Energy Independence setup supports homes in need of whole home backup. Their IQ Battery systems work well with Lumin energy management systems, which come in the form of either a subpanel or modular devices that connect to your circuit wires. While they're on the lower end of capacity and power, if you have or want to install a solar energy system with Enphase's popular microinverters, you'll likely want to choose their batteries for full home backup.

Generac

Best for: generator integration

• Maximum capacity: 36 kWh

• Peak power: not provided

• Continuous power: 11 kW

• Smart panel compatibility: Generac PWRmanager

Generac is a household name that entered the battery industry in 2019 when they acquired battery manufacturer Pika Energy. Generac offers the smallest system in our whole home backup lineup, but their PWRcell batteries can uniquely integrate with their PWRgenerator to keep your home running for long-duration outages (especially when the sun isn't shining). In fact, Generac's PWRgenerator is the first generator of its kind designed to recharge a battery system directly!

Generac also offers their own energy management system called the PWRmanager, which integrates with their battery system to help manage your largest loads.

HomeGrid

Best for: high electricity households

• Maximum capacity: 576 kWh

• Peak power: 24 kW

• Continuous power: 16 kW

• Smart panel compatibility: Savant

If your household consumes a lot of electricity and you want to be energy-independent, HomeGrid is a great solution. Of the battery systems on our list, theirs can reach the highest capacity and highest power output, making them a great choice for whole home backup. HomeGrid's battery setups are also highly customizable due to their modularity: you can stack up to eight battery modules, each of which is 5 kWh. The modules stack similarly to Legos, making it easy to add additional capacity down the road if you decide you need more backup.

HomeGrid batteries paired with Sol-Ark inverters integrate with the new Savant Power System, an energy management system that makes regular electrical panels smart.

SolarEdge

Best for: electric vehicle (EV) charger integration

• Maximum capacity: 87.3 kWh

• Peak power: 7.5 kW

• Continuous power: 5 kW

• Smart panel compatibility: Lumin and Span

SolarEdge is another big name in the solar industry, primarily known for their optimized string inverters that convert power at the string level but provide panel-level performance optimization and monitoring. SolarEdge recently launched the SolarEdge Home, a whole home solution designed to help you control your energy all in one place: the SolarEdge app. With a SolarEdge Home setup, your SolarEdge Home Battery and EV Charger connect directly to the Hub Inverter, reducing the need for additional writing.

SolarEdge batteries can also directly integrate with Lumin or Span energy management systems to provide detailed monitoring and control over individual circuits on your electrical panel.

Can solar panels withstand hurricanes?

Yes, solar panels can withstand hurricanes! Hurricane Ian caused wind speeds up to 155 mph, but most solar panel projects fared extremely well – one solar-powered community didn't lose any power and only experienced minimal damage. 

How much is a whole house battery backup?

A whole house battery backup system will likely cost at least $40,000. However, if you want to power your home solely on a battery for more than a day, expect it to cost upwards of $80,000 to $100,000.

How long will 10 kWh power a home?

Typically, you can power the essentials – like your phone, computer, Internet, refrigerator, and some lights – for about 24 hours with a 10 kWh battery. If you're trying to power a heat pump or an air conditioner with your 10 kWh battery, you'll likely only be able to run it for about three hours.

Thinking about installing a solar-plus-storage system for whole home or partial backup? On the EnergySage Marketplace, we'll connect you with our pre-vetted network of solar-plus-storage installers. When you register your property, you'll receive multiple quotes from installers so you can compare options head-to-head. If you're looking for specific equipment – like one of the batteries we mentioned in this article – simply make a note in your profile to let installers know. Or, if you're still struggling to make a decision, reach out to your personal Energy Advisor who can help guide you through the process (for free!).