Villara Energy Systems VillaGrid: The complete review

VillaGrid review

Villara Energy Systems, located near Sacramento, California, is part of the Villara family of companies (established in 1947), which has been installing home energy equipment (including solar, batteries, and generators) for about 20 years. In 2021, it launched the VillaGrid, the only 20-year home battery currently available on the market. The VillaGrid is the industry's first lithium titanate (LTO) home battery, with power, safety, and longevity as the core of its purpose. With its long warranty and extended battery life, coupled with the ability to work in extreme weather conditions, it's a great option if you're considering installing a home storage system.

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Key Takeaways

  • The VillaGrid is the longest-lasting battery available for residential use in the market currently and comes with a 20-year warranty (double the industry standard).

  • The VillaGrid can be tailored to fit the storage needs of individual homeowners and is meant to increase energy accessibility during unexpected or scheduled power outages and reduce electricity bills.

  • The VillaGrid is a modular system and can be stacked together to create larger, more powerful battery systems to match the needs of an individual home.

  • The industry's first lithium titanate (LTO) home battery, the VillaGrid, is the only nonflammable lithium-ion battery chemistry in the market, making it extremely safe.

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The VillaGrid pairs well with solar panel systems, especially if your utility has reduced or removed net metering, introduced time-of-use rates, or instituted demand charges for residential electricity consumers. Installing a storage solution like the VillaGrid with a solar energy system allows you to maintain a sustained power supply during both day and night, as long as you store enough energy from your solar panels when the sun is shining.

The VillaGrid is sized for day-to-day use at your home and can only pair with Sol-Ark inverters, with additional inverter options to be added in the future. When your solar panels produce more electricity than you can use in your home, you can store the excess electricity in the battery system instead of sending it back into the grid. Later, when your panels aren’t producing enough electricity to meet your home'saren't needs, you can use the stored energy in your VillaGrid battery instead of having to buy it from your utility company.

The VillaGrid is a high-power density, high-efficiency battery that is elementally different from other batteries currently available on the market. With the longest warranty and the widest operating temperature range in the industry, this battery is quickly gaining traction among homeowners looking for storage. The VillaGrid can be tailored to fit your individual storage needs and is meant to increase energy accessibility during unexpected or scheduled power outages.

When evaluating the VillaGrid, there are various important metrics and technical specifications to keep in mind. Among the most important are the size of the battery (power and capacity), its chemistry, depth of discharge, and roundtrip efficiency.


The VillaGrid comes in two sizes, 5.75 and 11.5 kilowatt-hours (kWh). Two important metrics to keep in mind when comparing the VillaGrid to other home storage options are power and usable capacity. Power (measured in kilowatts, or kW) determines the maximum amount of electricity that can be output at a single time, while usable capacity (measured in kilowatt-hours, or kWh) is a measure of the maximum amount of energy stored in your battery that you can actually use on a full charge. The VillaGrid includes a maximum peak power rating of 30 kW and a continuous power rating of 10 kW to go along with 5.75 or 11.5 kWh of usable capacity for either of the models.

The VillaGrid is also modular; it can be stacked together to create even larger, more powerful battery systems. The module architecture of the battery also makes it very serviceable in the field: the front cover can be professionally removed by a qualified contractor to reveal five individual battery modules, and some updates can even be done remotely over the Internet.

Basic functionality

The functionality of one solar power battery next to another can vary; some batteries have excellent off-grid capabilities, while others offer software solutions specific to rate arbitrage. Here are the important qualities of the VillaGrid:

Backup power

In case of a power outage, you can store the excess energy generated by your solar panels in your VillaGrid storage system so that it's available even when the sun goes down. With the large, long-lasting battery as well as some minimal energy conservation efforts on your end, the VillaGrid can continue supporting your electricity needs until the following day – even while the grid is down!


The VillaGrid is the industry's first available lithium titanate (LTO) home battery. Most lithium-ion batteries use graphite as their anode (check out this article to learn how batteries work), which is made of carbon and is flammable (though still very safe). However, LTO battery cells don't include any carbon, meaning they aren't flammable and can provide you with extra peace of mind. Villara's LTO battery can also handle a wide range of temperatures, charging and discharging down to -22 degrees Fahrenheit and up to 131 degrees Fahrenheit.

Performance metrics

Two key ways to evaluate the performance of a solar battery are its depth of discharge and roundtrip efficiency.

Depth of discharge (DoD) indicates the percentage of a battery's energy that has been discharged relative to the overall capacity of the battery. Because the useful life of a battery decreases each time you charge, discharge, and re-charge it, many battery manufacturers specify a maximum DoD level for optimal battery performance. In general, batteries with a higher depth of discharge are considered higher-quality products. The VillaGrid boasts a depth of discharge of 97 percent across all battery sizes, reflective of its safe and advanced LTO battery chemistry.

Roundtrip efficiency is a measure of the electrical losses involved with charging and discharging a particular battery. The higher the percentage, the more efficiently the battery is able to convert incoming electricity into stored electricity and then back into usable electricity. VillaGrid has a roundtrip efficiency of 98 and 99 percent, depending on the model; this means that for every 10 kilowatt-hours (kWh) of electricity, you put into the battery, you’ll receive 9.8 or 9.9 kWh of output, respectively. It's important to note that roundtrip efficiency can be difficult to compare, depending on if manufacturers report alternating current (AC) to AC or direct current (DC) to DC and the rate of charge and discharge.

In most cases, homes with a VillaGrid will charge and discharge their battery every day. So, how long does the VillaGrid last? The battery comes with an industry-leading 20-year, or 10,000 cycles/throughput, warranty, and Villara guarantees that the battery will maintain at least 70 percent of its capacity to hold a charge during that time period.

Villara battery technology is similar to other rechargeable batteries, both large and small: as time goes on, the battery loses some of its ability to hold a charge. Think of how the battery life of a brand-new smartphone compares to one that is a few years old. As you continually charge and drain your phone's battery, it starts to lose some of its ability to hold a charge.

The battery life of your VillaGrid will deteriorate in the same way. That isn't an indicator of a product flaw – all batteries lose some of their ability to hold a charge over time after extended usage, whether it's an electric vehicle battery, a home energy battery, or a rechargeable AA battery. This is why Villara Energy offers a warranty that guarantees at least 70 percent of the original storage capacity will remain after 20 years.

If you want to compare individual battery models side-by-side, our battery Buyer's Guide lets you select products and compare them based on efficiency, capacity, power, and more.

A solar battery installation isn't as simple as a list price for a component – depending on your electrical setup, among other factors, installation costs can vary widely. While Villara hasn't yet released information on the cost of the VillaGrid, you can expect it to cost significantly more than a lithium-ion battery. However, Villara states that when you factor in the capacity and long lifetime of the VillaGrid, the cost is very competitive with lithium-ion alternatives.

If you want to install the VillaGrid as part of a solar-plus-storage system, battery costs are just one part of the equation. A 5 kilowatt (kW) solar energy system costs anywhere from $9,000 to $15,000, depending on where you live and the type of equipment you choose.

That may sound like a lot of money, but installing a solar-plus-storage system can be a worthwhile investment. Whether or not the VillaGrid makes sense for you is determined by the way that your electric utility structures its rates, as well as how much you value energy security for your household.

In some cases, depending on where you live, you may have access to financial incentives that can reduce your home energy storage installation costs. For instance, if you live in California, you could get a cash rebate that covers most of your home battery costs through the Self-Generation Incentive Program (SGIP). Other states (such as Massachusetts) are in the early stages of evaluating battery storage performance incentives as well, and several states already provide cash rebates.

Whether you want to install a VillaGrid or another home battery, you will most likely need to work through a certified installer. Adding energy storage technology to your home is a complicated process that requires electrical expertise, certifications, permits, and knowledge of the best practices required to install a solar-plus-storage system correctly.

A qualified EnergySage-approved company can give you the best recommendation about the VillaGrid and other energy storage options available to homeowners today. If you are interested in receiving competing installation quotes for solar and energy storage options from local installers near you, simply join the EnergySage Marketplace today and indicate what products you're interested in your profile's preferences section.

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