If you add solar panels to an existing system, you can increase your solar electricity generation, extend the life of your installation, and create further savings on utility energy costs.
If there’s enough available installation space, the cost of adding extra panels may be beneficial to maximize your long-term savings, energy independence, and environmental impact with more solar capacity.
This guide outlines the benefits of expanding a solar system, the associated costs and savings, and the steps you can take to upgrade your home’s photovoltaic (PV) system.
The benefits of expanding your solar array
Adding more solar panels can be a valuable decision to help increase your PV system’s value, capability, and longevity.
1. More solar capacity to meet your increased electricity demands
If your home’s average electricity consumption increased after you went solar, you may not be able to offset as much of your energy bill as in previous years. Today, the cost of adding extra solar panels may be worth it for increased solar savings after:
- Replacing gas-powered appliances with electric alternatives for water heating, air conditioning, cooking, and other home systems.
- Purchasing or leasing an electric vehicle (EV) and charging your EV with solar for the lowest possible ongoing energy costs.
- Adding a new family member, roommate, tenant, or additional living space to your property.
- Your original system wasn’t sized to cover 100% of your energy consumption.
Beyond financial savings on utility bills, increased solar capacity can also help to keep your home running on as much clean energy as possible, which further offsets your carbon footprint in areas where grid electricity is produced by fossil fuels. For context, fossil fuels accounted for about 60% of U.S. electricity generation in 2023.
2. Ability to maximize savings within your net metering agreement
When you expand your existing solar array, the panels’ electricity production may be credited to your utility bills within the structure of your current net energy metering (NEM) agreement. But in states like California, among others, where NEM 3.0 or a net billing tariff is in place for new solar installations, homeowners locked into NEM 1.0 or NEM 2.0 can increase the benefits of their existing net metering rates with a small PV system expansion—though it can be no more than 1 kW or 10% of your existing system size.
Another option is Enphase Power Control, which is a proprietary software you can include with your Enphase system expansion. It allows you to add more capacity but limits the amount of excess energy you export to the grid so you can maintain NEM 2.0 status. You can learn more about Enphase PCS here.
3. Great opportunity for PV system upgrades or inspection
When you add more solar panels, it’s a good time to consider other PV system upgrades with the help of a professional already on-site. For example, if you plan to add a few extra panels to an existing system, integrating a home solar battery with backup for resilience at the same time could be more cost-effective than if you wait to install energy storage in the future.
Upgrades aside, the installation of new panels is also an excellent time to have a professional inspect your system’s hardware to confirm there are no signs of damage. To keep your system working as efficiently as possible, some solar panel cleaning or maintenance may be required.
Calculate: Is the cost of adding extra solar panels of value
To determine if adding extra panels will be worth it to reduce your ongoing energy costs, you can estimate the solar ROI of your system upgrade in a relatively straightforward, two-step process.
Step 1: Estimate the costs of adding extra solar panels
The cost of adding extra solar panels varies based on several factors, including the number of panels, the installation’s complexity, and if any other upgrades are required. Additional solar capacity typically costs between $800 and $1,600 per panel, though every project is different. To help you estimate the cost of adding extra solar panels to your system, here’s a breakdown of the factors that will affect your project’s bottom line:
- Panels, hardware, and wiring: In addition to the costs of the extra panels themselves, system expansion also incurs expenses for mounting hardware, wiring, and other minor installation features.
- Inverter costs: Whether your solar power system uses a central inverter or panel-level microinverters will greatly affect the costs and plausibility of your upgrade. When you add more panels to a string inverter-based system, a costly replacement will likely be required for the entire system, whereas panels with microinverters can be added one by one to design the optimal PV installation. This modularity also makes it easier to expand your system incrementally, so that you can add panels as your energy needs grow.
- Tax credits and incentives: To lower your total investment when adding solar panels to an existing system, you may be eligible for a federal tax credit worth 30% of project costs in addition to any local incentives available through your city, county, state, or utility.
Step 2: Estimate your future utility bill savings
The second step in determining if a system upgrade will be worth it is to compare the costs of adding extra solar panels to the potential utility bill savings that they can deliver. Much like when you first designed your home solar installation, you and your installer can use a PV system estimator to calculate the precise energy bill offsets you can expect from your additional capacity.
Across the country, a PV solar system can help deliver increased utility bill savings in areas with rising energy prices or time-of-use rates, where electricity costs more during peak hours. To calculate your precise savings, it’s also important to verify whether your system expansion can be added to your existing net metering contract or if policies have changed in your area.
Get started with your solar system upgrade
Whether you add more solar panels, integrate battery storage, or want to explore other ways to maximize the value of your PV system, high quality equipment and local expertise are essential to ensure your upgrade is worth it.
Enphase Energy Systems feature advanced performance technology, industry-leading warranty coverage, and complete app-based control for the best overall home solar experience. Designed for easy and cost-effective system expansion, Enphase is your partner in long-term residential solar savings.
Upgrading your solar system FAQs
How do I add solar panels to my existing system?
If you want to add solar panels to your existing system, the first step is to contact your original installer or another certified PV professional. During your consultation, you can determine which upgrades will be necessary to accommodate the new panels.
Is it worth adding more solar panels?
Yes, if your electricity usage has increased, the addition of more solar panels may be worth it to lower your future utility bills. Adding extra solar capacity to an existing array also provides a great opportunity to perform a professional inspection, clean your PV panels, or integrate home battery storage.
How much does it cost to add more solar panels?
The cost to add more solar panels depends on the number of panels, the installation’s complexity, and many other unique project factors. When adding panels to an existing system, your upgrade may also qualify for tax credits or solar incentives to lower your investment costs.
Will my existing inverter handle the additional panels?
If you have a string (or central) inverter, it may not be rated to handle the increased energy capacity from additional solar panels. This could necessitate an inverter upgrade. If you have a microinverter system, each panel will be installed with its own inverter. Therefore, your additional solar capacity won’t affect your existing hardware in the same way.
How often do solar panels need to be replaced?
Most solar panels have performance warranties that last for 25 or 30 years and only need to be replaced in rare occurrences of malfunction or damage. Solar panel replacement should always be performed by a professional, and safe disposal of the equipment is essential, as over 85% of a PV module can be recycled.
