Can you add solar panels to your home solar system? The answer is generally yes. Should you add panels to your existing system? That’s a tougher question.
Increasing the size of your solar panel system is more complex than just tacking a few more panels up because you want more solar energy for your home. Your budget, your system’s efficiency, and the specifics of your net metering plan are some issues to consider. Here, we answer the frequently asked questions about adding more home solar panels to an existing home system.
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If I Install Solar Now, Can I Add More Panels Later?
If you’re interested in solar but don’t want to dive into the deep end immediately, it’s logical to think, “Hey, why don’t I just buy a few solar panels now and then add more later.” Unfortunately, it’s not as simple as that.
In reality, building a solar energy system is generally not a piecemeal process, like gradually building up the inventory of tools and hardware in your garage. Instead, most solar energy systems are designed uniquely to fit a specific function, and adding more panels later can create a waterfall effect in which the extra power produced will impact other system components.
For instance, adding more capacity means you may need to rewire your existing panels or upgrade the inverter from the original installation – if you have the room on your roof or property to accommodate the new panels in direct sunlight. String inverters are designed to accommodate a specific number of panels, so adding more solar panels usually requires adding more inverter capacity. On top of this, adding more solar panels to your solar power system will also send you back through the permitting process – putting yet another line item on your project sheet.
With expenses for the new panels, upgraded equipment, labor, and permitting, the costs of putting up solar panels in portions can outweigh the financial benefits of the added solar generation. Knowing this, many installers, like Palmetto, recommend designing your solar energy system to meet your home's entire electricity needs during your initial installation.
However, there are instances in which you may be able to add solar panels to an existing system later and it’s a good investment, such as after a dramatic increase in your home’s electricity demand from buying an electric vehicle.
How Much Does it Cost to Add Solar Panels to an Existing System?
The cost of adding solar panels to an existing system increases with each panel you install. While solar panels retail for a few hundred dollars each, remember that you will also incur costs for the extra wiring, racking, permits, and other necessary upgrades.
All in all, adding a few extra solar panels could cost anywhere between $2,000 and $20,000 (or more!) depending on what upgrades are required. Your project costs may also vary depending on whether your solar installation uses individual microinverters or a central inverter system.
Does Adding Solar Panels to a System Earn a Tax Credit?
Although circumstances vary, yes. In general, the costs of adding solar panels to an existing system can qualify for available incentives such as the federal solar tax credit.
According to an IRS rule, “Earlier installations of qualifying property do not affect the availability of the credit for qualifying property in later years.”
In other words, even if you already utilized the residential solar tax credit, new purchases and installations will likely qualify for the tax credit. That said, we advise consulting a tax professional to determine if your specific upgrade will qualify.
Is Adding Solar Panels to an Existing System Worth it?
If you are not producing enough solar energy to meet your home’s power demand, adding solar panels may be worth it if they can lower your remaining electricity bills from the utility company and pay for themselves over time.
If you have an older system, you may want to boost your production by installing more solar panels. This is often accomplished by adding the new system alongside the existing system so that both work together.
Today, many solar customers consider solar expansions after electrifying their homes or vehicles and consuming significantly more annual power.
Can I Add Solar Battery Storage to an Existing Solar System?
In most instances, yes. You can add a solar battery to an existing solar panel system. While we have illustrated all the challenges installing additional solar panels can bring, adding a solar battery is generally less involved. However, an inverter upgrade may still be necessary, and you may need additional permits and other approvals. Adding a solar battery allows you to store and use more of your solar energy at home rather than exporting all excess production to the energy grid.
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Will I Lose Net Metering if I Expand My Solar Panel System?
Where net metering plans have changed, you may lose your net metering plan or be changed to a different plan by adding solar panels to your existing system, depending where you live. Net metering plans generally have an expansion threshold a user must remain below to stay in the current plan. For instance, adding more than 10% of panel capacity to a system, could result in a forced plan change to lower rates or in being ineligible for net metering.
In California, for instance, if a customer on NEM 2.0 adds solar panels which add more than 1 kW or over the 10% capacity threshold, they are subject to being moved to NEM 3.0.
In Illinois, you can expand your solar panel capacity and remain on your current net metering plan as long as you don’t expand your system by more than 100% or your changes don’t need a new interconnection agreement. It’s important to check with your utility company, state, or a reputable solar company for information and policies specific to your area.
Can I Add Solar Panels to an Existing System Myself?
While a few solar owners might have enough technical and electrical know-how to add solar panels to their existing system, you shouldn’t tackle this on your own, for safety and legal reasons.
Working with electricity up on a roof can be dangerous. Unauthorized work could void warranties, insurance, contracts, permits, and other agreements with a company, utility, or government. An inexpert installation could leave you with an inefficient or malfunctioning system.
Another option is maximizing your existing solar savings by making your home more energy efficient. You may be able to offset more energy usage with appliance upgrades, improved insulation, or moves toward home electrification.
Palmetto can help you design a home solar system and identify home energy solutions that can save you energy and money at home.
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Frequently Asked Questions
Can you add solar panels to an existing system?
You can add panels to an existing system. However, whether adding panels is practical or will make financial sense are different questions and not always a “yes.”
Can I add solar panels to my system on my own?
It’s highly inadvisable to add solar panels to an existing system on your own. You could run into safety hazards, especially while working with electricity. Tackling the job on your own can void warranties, contracts, and insurance policies pertaining to your solar system.
How much does it cost to expand a solar panel system?
The cost of expanding a solar panel system depends on how many panels you’re adding to it. The best way to understand your project’s cost is to reach out to a reputable solar company for a quote.
Disclaimer: This content is for educational purposes only. Palmetto does not provide tax, legal, or accounting advice. Please consult your own tax, legal, and accounting advisors.
Andrew GiermakWriter and EditorAndrew joined Palmetto in Charlotte in August 2024. He’s been a writer in journalism, then in business, going back to almost the 20th century. He’s lived in Indiana, Virginia, Pennsylvania, Virginia again, and now North Carolina for the last 12 years. He likes golf. Is he good at it? Not so much.
