add solar panels to existing system

Can You Add Solar Panels To An Existing System?

You've already reduced (or maybe eliminated) your electricity bill if you've gone solar. However, you may wish to add more solar panels to your existing system; your solar panel system may have been undersized, to begin with, or your power demand may have grown after installation owing to new additions to your home, new appliances, or the purchase of an electric vehicle (EV).

The procedure of adding extra panels to your existing system will not be the same as it was when you were looking for a solar panel system in the first place. Here are a few crucial considerations to bear in mind while you research your alternatives.

Factors to consider when adding new solar panels to an existing installation

Energy requirements

How many more solar panels do you require? This will be the first question to address since it will have an impact on both the design of your system and the cost of the add-on project.

The number of panels you'll need for your system will be determined by a variety of criteria, including your post-solar power cost, where you reside, the equipment you have, and the design of your system. If you can supply your installer with your power bill information since adopting solar, they should be able to estimate how many extra panels you'll need based on your specific scenario. If you want to figure out how many solar panels you'll need on your own, check out our guide to figuring out how many solar panels you'll need.

There is room for new panels.

Do you have adequate room to put more solar panels? The answer may be no if you have a rooftop system with a limited area. Because property owners with ground mounts often have a lot of sunny areas accessible for installation, ground mount systems can be a little easier to build onto.

However, just because you don't have enough roof space to add more panels doesn't mean you should abandon the project. Installing additional solar arrays on other structures on your property, such as carports, sheds, or gazebos, is always a possibility.

Upgrades to solar panels and compatibility

What panels did you use in your initial installation, and do any of them need to be replaced? Your solar panels will generate power for more than 25 years, after which you may notice more substantial drops in output, so you won't need to replace the panels from the original installation. However, you should still have your installation thoroughly inspect everything, including the racks and wiring.

if possible, Installing additional panels of the same type as your original array is a smart idea. This guarantees that everything looks the same and has the same power outputs and efficiency as your other panels. If you can't install the exact same panels, seek replacement panels with the same or similar power output — otherwise, you risk damaging your old array.

Replacement of inverters

Is your inverter big enough to handle the extra panels? You may need to replace your inverter depending on how much more capacity you add to your system. The power output of your panels is used to size your central inverter by an installation. Because the direct current (DC) electricity generated by your panels is converted to alternating current (AC) at the inverter, the power rating of the inverter may be slightly lower than that of the panels due to energy loss during the conversion process. If you add a big number of panels and your overall solar panel system is substantially larger than the initial size, it may create more power than your present inverter can manage.

If your initial solar panel system employs microinverters rather than a power optimizer or string inverter system, add-on projects are a little easier. You don't have to worry about inverter capacity difficulties since microinverters are situated at each individual panel, and you can simply install extra microinverters with the new panels.

To install the panels, you'll need an installer.

Is your original installer capable of working on add-on projects? If that's the case, it'll be simplest to contact them first to see if they can help. They'll be familiar with your system and property, so they'll be in the greatest position to add additional panels to their own job.

However, if you had a negative experience with your previous installer or they've subsequently gone out of business, this may not be a choice for you. When it comes to adding extra panels to your solar array, you can always look for a new installer to perform the job, but finding a solar firm to do the job may be more difficult. Some installation companies will refuse to work on add-on projects for installations that are not theirs.

This happens for two main reasons: they don't want to deal with contradictory warranties on the total installation, or the job isn't large enough. Many installation companies will not want to get into an argument later on over whose responsibility it is to fix a section of the system, especially if the initial work is not their own and they cannot stand by it.

In terms of system size, many installers have a minimum system size that they will install in order to maintain their profit margins. A typical add-on project may include installing only a few panels, which will result in far less profit than a conventional home installation. Many businesses will prefer to focus their attention on larger projects based on their resources and installation schedule.

Permitting and interconnection

Will adding extra panels on your property need obtaining new permissions or submitting additional hook up papers to your electricity company? This might vary depending on a number of things, such as the number of extra panels you're adding, if a new inverter is necessary, and the permitting procedures in your location. If you add more than a few kilowatts (kW) to a system and need to change your inverter, you'll most likely need to file another interconnection application to your utility provider.

Any installer you engage with for an add-on project should be aware of any permissions or connections needs and will assist you in filing for these as part of the overall cost of the add-on project.


You might not be eligible for some of the same incentives (like tax credits and rebates) if you're adding more panels to your system. Many incentives can only be used once per person or property.

When it comes to add-on projects, performance-based incentives (PBIs) might be challenging. Because the incentive amounts are depending on the quantity of power your system generates, if you have a new inverter and need to re-file for interconnection, you may run into some issues.

When it comes to your add-on solar project, always talk to your solar installer about what incentives you will and will not be qualified for, and consult a tax expert or accountant if you have any doubts about tax credits you may be entitled to.

If your roof doesn't have enough room for your extension, a ground-mounted system may be an option. A ground-mounted array can boost your capacity without taking up more roof space by utilizing some free area in your garden. Ground-mounted solar panels are simple to install and, in most situations, are less expensive than roof-mounted panels. They're also simple to clean and fix if something goes wrong in the future. You may even consider a tracking array, which rotates during the day to optimize solar exposure if you have enough open area. These systems are even more energy-efficient than standard roof systems, allowing you to get the most bang for your buck when it comes to roof upgrades.

A solar upgrade is available to almost all solar clients. Expansions are so prevalent that your system may have been built with an upgrade in mind from the start. If you haven't yet built a solar system, you should think about installing a bigger inverter to make future upgrades as straightforward as feasible. Get started by requesting a free quotation on our website, then speak with your installer about the possibility of extending your array in the future.