Upgrading an old solar system: What you need to know

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Upgrading an old solar panel system

Home solar systems have been around for quite some time, reliably powering homes nationwide with clean, renewable energy. If you were an early adopter, your system is likely getting up there in terms of age. Although solar panels last for 25 to 30 years on average, you might encounter some defects, general wear and tear, or a drop in electricity production brought on by age with an older system. Whatever the reason, if your solar system is no longer producing the energy you need, we’re here to show you some of your options.

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Key takeaways

  • With an older solar system, you can often run into issues when trying to replace individual components.

  • Replacing your entire system will cost more than replacing individual parts but will generate substantially more power than your current system.

  • If your system isn’t nearing the end of its life, you might consider just expanding your solar system.

  • Visit the EnergySage Marketplace to compare multiple quotes for solar system replacements or expansions.

If you’ve noticed any common solar panel defects affecting your system, replacing some individual parts might be your best bet. This can often be accomplished relatively easily through your original installer, who can help you get the parts that best fit your specific system. However, you’ll want to be aware of some potential issues that could arise when trying to switch out individual parts in this manner.

Solar panels

You might want to replace specific panels if defects like microcracks or snail trails have lowered the output of individual panels. The first issue that could arise with swapping out panels is the availability of substitutes. The manufacturer may not have the older panels' model in stock, or it could have gone out of business entirely. You can sometimes use similar panels, but you still need to match a bunch of electrical specifications–i.e., wattage, number of cells, physical dimensions to fit into the array–of the new panels with your old ones, which can be tricky.

Additionally, standards and requirements–i.e., fire ratings, groundings, cable housings–regarding panel specs have changed over time, which means although you can still use your system in its original configuration, you could run into problems with upgrades. Finally, if the installer you’re working with now is different from the one who installed your original system, they may be reluctant to switch out panels on your existing system, as they cannot back the quality of the original installation.


If you’re noticing performance issues with your solar system, consider replacing your inverters. While microinverters last about 25 years, string inverters need to be replaced around the 10 to 15 year mark, so if you have an older system, your inverters may be nearing their lifetime. The first potential issue here is warranty. If your inverter is failing within the warranty period, the manufacturer should replace it, but if the warranty period has passed, you’ll have to pay for a replacement yourself, which could be expensive.

You also might run into a problem with availability: just like with panels, the original manufacturer may have gone out of business. However, similar to panels, you might be able to get around this by getting another inverter with the same specs–just be sure to discuss this with your installer.

Finally, if you’re switching out older string inverters for microinverters, be aware that your installer will first need to remove all your panels to add microinverters to each one. Microinverters offer a number of important advantages over string inverters, so this shouldn’t be a deal breaker, but you should be aware of this step in the process.

If your system is nearing the end of its lifespan–meaning that there are not really specific issues with individual parts other than the degradation of the whole system–your best option might be to replace the entire thing.

The benefits of this? You’ll likely get a significant boost in power output. Your new system will produce more energy than your original system was capable of, even when it was brand new since new panels produce more power more efficiently than old ones. (Panel costs have dropped sharply in the last decade, while power output has grown significantly, with average power outputs now ranging from 250 to 400 watts)

What’s the downside? Doing a full system replacement is usually more expensive than replacing individual parts, as your installer will need to remove your existing system and install a brand new one. If you’re interested in getting the lowest price for the highest quality of work on a job like this, check out the EnergySage Solar Marketplace, where we’ll connect you to the best local installers.

If your system works relatively well and you’re just looking for more power output, you should consider expanding your solar system. This typically works by your installer placing another smaller, newer system alongside your existing one to complement its power output. You’ll probably get some good bang for your buck with the new smaller one due to the increased power output of modern panels. Before doing this, you’ll want to ensure you have enough space on your roof or garage to house such a system. If you have this option, many installers prefer this over replacing panels since they don’t have to deal with the hassle of matching the original system. If you’re interested in expanding your system, your next step is to reach out to your installer or sign up on the EnergySage Marketplace.

If you have further questions about what to do regarding issues with your current system, you should contact your original installer, if possible. If you’re in the market for a new or expanded system, visit the EnergySage Marketplace, where you can get multiple quotes from local installers and help from our expert Energy Advisors on any questions you might have at no cost.

Find out what solar panels cost in your area in 2024
Please enter a five-digit zip code.
  • 100% free to use, 100% online
  • Access the lowest prices from installers near you
  • Unbiased Energy Advisors ready to help
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