Should you buy the Kohler Power Reserve solar battery?

Updated

Installation setup of the 20 kWh Kohler Power Reserve solar battery.
Installation setup of the 20 kWh Kohler Power Reserve solar battery. Image source: Kohler Power

If you own a home (or ever lived in one, really), the name Kohler probably rings a bell. Kohler has made everything from sinks, to toilets, and even cabinets. But what you might not realize is that Kohler isn’t just a leader in plumbing equipment, but in power generation, as well. 

In fact, Kohler built the first modern-day generator back in 1920, and it’s still a trusted name in backup power today. Despite that, even a 100-year old company can still experience some “firsts”. Having seen the importance that clean energy plays in having a sustainable future, Kohler Power released its first residential solar battery - the Kohler Power Reserve

But does the Kohler Power Reserve energy storage system live up to the company’s high quality standards and outstanding legacy? And being that it’s offered at a higher price point than competitors like the sonnenCore and Tesla Powerwall, is it worth the extra cost?

On this page

    Find out if installing solar-plus-battery storage is worth it in your area

    How does the Kohler Power reserve work?

    The Kohler Power Reserve is a lithium-ion solar battery (more specifically, it’s a lithium iron phosphate, or LFP battery) that stores the excess solar energy a solar system produces. 

    The stored power can then be used to run the house at a later time when the solar panels can’t meet the home’s energy needs (like during a power outage) or when the sun goes down. When you add a solar battery to your home solar system, you then have what is known as a “hybrid solar system”

    Watch the below video to get a better understanding of how solar panels and batteries work together to power homes: 

    Homeowners can choose between four different operating modes for the Power Reserve: 

    • Backup mode, where the battery remains charged and only discharges in the event of a power outage
    • Self-Supply mode reduces the amount of electricity a home takes from the utility grid. It charges the battery with excess solar power during the day and discharges to power appliances later, when the solar panels aren’t producing electricity
    • Time-of-Use mode dictates when the battery charges and discharges, based on how much the utility is charging for electricity, allowing homeowners to save extra money on their utility bills
    • Custom mode allows homeowners to choose how their battery works based on their specific energy consumption habits

    How much does the Kohler Power Reserve battery cost?

    Kohler offers their solar battery backup system in three different sizes, so they have three different starting prices:

    Battery size Starting cost*
    10 kWh $13,325
    15 kWh $18,720
    20 kWh $23,440

    *Starting cost not including installation or incentives

    These prices are a bit higher than what you pay for some other leading solar batteries on the market. The 10 kWh sonnenCore battery, for example, costs around $9,000 before installation or incentives, while the 13.5 kWh Tesla Powerwall costs $8,500 before incentives or installation. 

    Does the Kohler Power Reserve qualify for the solar tax credit? 

    Yes, the Kohler Power Reserve qualifies for the 26% federal solar tax credit, so long as it is paired with a solar panel system

    Let’s say you purchase the 10 kWh Power Reserve. The installation costs an additional $2,000, bringing the total cost to $15,325. The federal solar tax credit would drop the price down to about $11,340.

    Another thing to take note of is the fact that the Power Reserve is OpenADR compliant, so it can participate in energy storage aggregation programs where available, which means your utility will pay you for access to the energy you have stored within your battery. 

    So, the Power Reserve could actually wind up earning you a little extra money from your utility if your utility has one of these programs, or is planning one in the future. You can find information about incentives and programs your utility offers here.

    Keep in mind, installation costs will vary greatly depending on the battery model, where you live, the design of the system, and the installer you choose

    See how much you will save monthly after switching to solar

    Find out how much a solar system would cost for your specific home

    Key specifications for the Kohler Power Reserve

    Kohler Power Reserve specs
    Specification DC model AC model (10 kWh) AC models (15 and 20 kWh)
    Usable capacity 10, 15, 20 kWh 10 kWh 15 and 20 kWh
    Chemistry LFP LFP LFP
    Continuous power output 7.6 kW 5.76 kW 7.6 kW
    Peak power output (60 seconds) 9.12 kW 5.76 kW 9.12 kW
    Round-trip efficiency 96.6% 96.6% 96.6%

    Usable capacity 

    The Kohler Power Reserve comes in three different sizes: 10 kWh, 15 kWh, and 20 kWh. The battery capacity tells you how much electricity the battery will store, and how long it will be able to run your appliances for. Offering a variety of sizes gives homeowners the opportunity to choose what size is best for their lifestyle.

    The higher your home’s power usage, the bigger the battery you’ll need. If you use a lot of electricity, a 20 kWh model may be the best choice for your home. However, most homeowners can get by just fine with the 10 kWh or 15 kWh batteries. 

    AC and DC-coupled 

    Aside from a variety of sizes, Kohler also offers their batteries in both AC and DC models, again giving homeowners more control over their battery system. 

    An AC-coupled battery is best paired with an existing home solar system. The battery has its own inverter, so it can be easily connected on the AC side of the existing solar inverter. 

    A DC-coupled battery is the better choice when you’re installing your solar panels and battery at the same time. The DC battery can be installed before the solar inverter and charged directly with the electricity produced by the solar panels, making them more efficient. 

    Learn more: AC vs DC-coupled batteries

    Continuous power output 

    Depending on the model you choose, the Power Reserve will release anywhere between 5.76 kW and 7.6 kW of continuous power. “Continuous power output” describes how much electricity a battery can release over an extended period of time, giving you an idea of what appliances it can run. 

    Most solar batteries today have a continuous power output of 5 kW. So, if you’re looking to run more power-hungry appliances, like a central air conditioner, the Kohler Power Reserve is a good choice

    Peak power output 

    While continuous power output measures how much power a battery can release over a sustained period of time, peak power output is the maximum amount of power a battery can release for a very short amount of time. 

    Peak power output is important because many appliances require more power when they turn on, and then draw less once they’re up and running. So, you need your battery to be able to release the amount of energy necessary to turn on your appliances, not just run them.

    In the case of the Kohler Power Reserve, the battery will release between 5.76 kW and 9.12 kW of power for 60 seconds, depending on the model. Most batteries on the market today have a peak power output of around 7 kW for just 10 seconds.

    If you’re looking to run something like a sump pump or an air conditioner that needs a lot of electricity to power up, any of the Kohler models besides the 10 kWh AC would work best for you.

    Round-trip efficiency 

    When power is sent to a battery, some of that electricity is used to facilitate the storing process, which means all of the electricity your panels produce won’t be stored for you to use. The round-trip efficiency of a battery gives you an idea of how much electricity is lost to that storing process.

    The higher the efficiency rating, the better. Most batteries today have an efficiency rating of at least 90%, with a lot of them coming in around 95%. The Kohler Power Reserve has a round-trip efficiency of 96.6%, which is good in our book. 

    Chemistry 

    The Kohler Power Reserve is a lithium-ion battery. More specifically, it’s a lithium iron phosphate, or LFP, battery. LFP batteries are able to remain stable at high temperatures, making them less likely to overheat and catch on fire than other types of lithium ion chemistries, like nickel manganese cadmium (NMC)-based batteries. 

    Don’t get us wrong, NMC batteries like the Tesla Powerwall and LG Chem RESU are still perfectly safe to install in your home, so long as they are handled correctly. But, if you want a little more peace of mind, an LFP battery like the Kohler Power Reserve could be the one to go with. 

    Kohler Power Reserve warranty

    The Kohler Power Reserve comes with two different warranties: a product defect warranty and a capacity warranty. 

    Product defect warranty 

    Under the product defect warranty, Kohler will cover qualifying defects of its energy storage system for the either of the following warranty terms, whichever comes first:

    • 10 years after the initial installation date
    • 10 years, starting 4 months after the system has been shipped from the factory

    This is pretty standard for product defect warranties. Anything less than 10 years should serve as a red flag. 

    Capacity warranty 

    Solar batteries, just like the batteries in your phone or laptop, lose the ability to hold a charge as time goes on. The capacity warranty gives you some insight into how long the solar battery will last as it is used. 

    Just like their product warranty, Kohler’s capacity warranty is close to what you’ll see from most solar battery manufacturers. Kohler states that the Power Reserve will operate at a minimum of 70% of its initial capacity during the first 10 years of operation, or until the battery has released 3 megawatt-hours (MWh) per kWh of storage capacity, whichever comes first. 

    Battery warranty language can be a bit confusing, so let’s simplify this by using the 10 kWh Power Reserve as an example. Based on the warranty terms, the 10 kWh Power Reserve would be able to release 30 MWh (or 30,000 kWh) of electricity before falling below 70% of its original capacity. 

    But, will you pass the 30 MWh threshold before you reach 10 years? Well, it depends on how the battery is used. If the battery is completely discharged every single day from the initial installation date, you would reach 30 MWh after about 8.22 years, meaning the battery wouldn’t be covered by the warranty for a full 10 years. 

    In order to actually reach the 10-year mark and maximize the amount of time that your battery is covered by the warranty, you could only use about 82% of the power stored in your battery daily. However, this is the case for most lithium ion batteries for sale today. 

    Can you go off-grid with the Kohler Power Reserve?

    Yes, you can go off-grid with the Kohler Power Reserve. This also means that the battery does not require connection to the grid to operate, making it a great choice for those with a cabin in the woods or a home in a rural area without reliable utility grid access. 

    Is the Kohler Power Reserve battery worth it?

    The Kohler Power Reserve is a great battery. It has impressive specifications like high power output, a decent warranty, and it comes in a variety of capacities so you can choose what size best meets your needs. Not only that, it can be monitored and controlled right from your phone

    The biggest downside to the Kohler Power Reserve is the price. At $13,325 for a 10 kWh battery before installation costs are considered, it is on the pricier side. But, the purchase does include an inverter, and you get all those great features we mentioned earlier. Plus, Kohler is a reputable brand so you can trust that the company will be able to honor their warranty and provide customer support for the lifetime of the battery, should you need it. 

    But, we have to be honest with you, whether it's the Kohler Power Reserve or not, most homeowners don’t need to get a solar battery. Batteries will add upwards of $13,000 to your solar installation without providing you very much (if any) additional electric bill savings, unless:

    • Your utility uses Time of Use rates
    • Your utility doesn’t offer net metering
    • Your area experiences frequent prolonged power outages
    • Maximizing the amount of clean energy your home uses is extremely important to you

    If none of these scenarios apply to you, investing in a solar battery doesn’t make a whole lot of sense. 

    With that said, if you are definitely in the market for a solar battery and value a good warranty and company reliability, the Kohler Power Reserve is worth buying.

    What does make financial sense for most American homeowners is switching to solar. To get an estimate of how much you can save with a solar power system, check out our free and easy-to-use solar panel cost and savings calculator. By using the calculator, you can also see how much adding solar batteries will add to your solar panel installation and how it will impact your payback period. 

    Find out how much a solar system would cost for your specific home

    Key takeaways

    • Kohler Power Reserve is a lithium ion solar battery ranging from 10 kWh to 20 kWh in size.
    • The price of a Kohler Power Reserve falls between $13,325 and $23,440, before installation costs or incentives.
    • The Kohler Power Reserve has both AC and DC models which boast high power outputs and increased safety over other batteries on the market.
    • Kohler offers a warranty that guarantees performance at at least 70% of the original capacity after 10 years, or after 3 MWh of throughput per kWh of storage, whichever comes first.
    • The Kohler Power Reserve is more expensive than some of its competitors, but with great specs, a good warranty, and a solid brand legacy backing it up, it is a great choice for homeowners looking for energy storage.
     

     - Author of Solar Reviews

    Catherine Lane

    SolarReviews Blog Author

    Catherine is a researcher and content specialist at SolarReviews. She has strong interests in issues related to climate and sustainability which led her to pursue a degree in environmental science at Ramapo College of New Jersey.

    Related solar news