How Long Do Solar Panels Last? - Longhorn Solar
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“How long do solar panels last?”

The question you’re probably looking to have answered is “How long should I expect my solar system to keep producing energy?”

The short answer?  25 years or more.  With the money you can save on your electric bill by going solar, it no surprise so many people are turning to solar energy production as the #1 alternative to utility power.

We’ve Got News, And The News Is Good

We used to think solar panels only lasted as long as their warranties (typically 25 years).  Entities like The National Renewable Energy Laboratory (NREL), told us that solar panels lost about 1% of their annual output each year, and we listened…because they’re NREL.

Advances in technology have seen the degradation rates of solar panels drop FAST, from 1% down to .5% or lower, depending on the manufacturer, which means your solar panels are going to be cranking energy out for a VERY long time.   Assuming some basic upkeep, your solar system should have no problem maintaining a minimum of 80% of its original rated output after 25 years of operation.  That’s the solar panel manufacturer’s warranty.  If they don’t maintain that at a minimum, they’re eligible for replacement.  That’s a lot of juice left in the tanks!

You might have to replace an inverter but that shouldn’t be a big deal.  That’s because as solar deployment has increased,  equipment costs in the solar industry have dropped at crazy rates.  

Assuming the system is kept in good working order, your solar system should still be cranking out a significant amount of energy well into the 30-40 year range.  With no moving parts and minimal upkeep, your solar system should pay for itself time and time again.  That’s great news for your wallet! The longer your solar panels last, the more money you save.  It’s the gift that keeps on giving.

Image Credit: Martin Holladay

Author, popular blogger and solar enthusiast Martin Holladay installed some solar panels back in 1980 that are still working today.  Check out his write-up about his (now 38 year old) solar installation HERE (2).  His book, Musings of an Energy Nerd, is an entertaining read for solar DIYers.

Your solar PV system will probably require some minimal maintenance over the years.  When we present solar to home and business owners, the lifetime production numbers include several factors that affect overall energy harvest.  One of those factors is soiling degradation (dirt, dust, tree pollen…and yes, bird poop).

If left alone, most solar arrays will be naturally cleaned by the weather.  Most areas in Texas receive enough annual rainfall to take care of this potential maintenance issue.  If you want to perform and annual or semi-annual cleaning, it can’t hurt.  Just make sure you use only distilled water, as residue left on the glass can decrease production.

You’ll want to make sure your solar array is clear of any falling debris risks.  Branches are heavy and can scratch or even crack the tempered glass on a solar panel.  You’ll also want to make sure trees and shrubs don’t cast shade on your solar panels, making them produce less energy.  You can usually gauge this from the ground in the morning or evening when shadows are the longest.  If you need to prune anything, just make sure nothing falls directly on the panels.  That’s it!

Depending on the type of inverter your solar system has, it may or may not need to be replaced before 25 years.  Most inverters have a minimum warranty of 10 years, with newer inverters ranging from 12-25 years.  For solar systems insalled before 2012-2013, replacing an inverter when will most likely mean adding online monitoring to your system.

If you currently have monitoring, there is a very good chance that the tech supporting the communication between your solar system and your smartphone/computer will become obsolete inside of 10 years.  Monitoring should be viewed as a convenience option, and only affects the ease with which you can see how well your solar system is performing.  These same readings can always be taken from the inverter’s display panel.

It’s no different than replacing an alternator on your 10+ year old car, or having to upgrade an outdated stock radio to a newer unit with an AUX input and Bluetooth so you can listen to your favorite Spotify playlist.  Some things you’ll have to do.  Others you’ll want to do.

So what does that mean for the future?

That’s a good question.  With the massive investments in solar R&D over the last 10 years, there’s really no telling what the then current technology is going to look like when/if you find yourself needing to replace and older component in your aging solar system somewhere down the line.  We’re already addressing challenges with add-ons to existing systems (finding solar panels that match the existing array’s module wattages and aesthetics).  We’re learning to be more proactive by changing the way we address system design during the initial presentation process, as well as preparing for the scenarios we can see coming in the future.

It’s going to be interesting to watch as the solar market continues to grow, and more and more home and business owners buy into solar.  The economics are such that it is fast becoming a foregone conclusion that solar makes sense for most properties.  History tells us that energy rates are going to continue to rise.  It’s just a matter of when the financial tipping point arrives in Texas that forces owners to finally take a very serious look at going solar.

Steve has served in the solar industry for over 10 years.  He holds a NABCEP Technical Sales Professional certification (#TS-102415-012889), and sits on the board of the San Antonio Solar Alliance.  For questions, comments or feedback, you can reach him via email at steve@longhornsolar.com