How Long Do Solar Panels Last?

If you’re thinking about investing in solar power for your home, you’re probably wondering how long that investment will take to pay off. A solar power system that functions for 30 years sounds like a good thing. One that wears out after ten years, not so much.

How long do solar panels typically last?

Modern solar panel energy systems can provide clean, sun-generated power for 25 years or more, if certain care and maintenance guidelines are followed. As with other household systems such as roofs, a certain amount of degradation over time is to be expected. Don’t let this deter you from investing in photovoltaic (PV) energy, though. Despite the fact that panels, inverters, and other components may eventually need replacing, a state-of-the-art solar energy system offers an excellent ROI while reducing your carbon footprint.

How is solar panel lifespan determined?

In the renewable energy industry, the natural tendency for solar panels to lose effectiveness over time is known as ‘degradation rate.’ The expected lifetime of solar panels is improving all the time, yet there remain many factors that can contribute to accelerated degradation of energy output.

Panels that are made today can be expected to provide clean free energy for a half century or longer. As far as older systems are concerned, some still function wonderfully. Other older systems may already be degraded to the point where inverters and panels should be replaced in order to bring the system back optimum efficiency.

Even the newest PV energy system is subject to unavoidable conditions such as weather cycles, shadows, and geographic location. Random events, including natural and man made disasters, can also adversely affect solar power efficiency over time.

As solar technology improves overall, manufacturer guarantees get longer. No matter what it says on your warranty, however, regular inspection and proper maintenance can dramatically extend the life of your sun-powered energy system while limiting the rate of solar panel degeneration.

Solar panel degradation defined

Solar panel degradation refers to the lessening of produced power over the lifetime of a solar panel. A 40-year study by the National Renewable Energy Laboratory [1] (NREL) revealed an average annual degradation rate of between 0.4 and 1 percent of generation efficiency. Calculated by analysis of both continuous and stand-alone data sets, the scientific study proved that solar panels degrade at differing rates, especially when they are made of diverse materials.

The NREL study examined solar collectors made of numerous materials, including amorphous silicon (a-Si), cadmium telluride (CdTe), copper indium gallium selenide (CIGS), multi-crystalline silicon (multi-Si), and monocrystalline (mono-Si) panels. Monocrystalline solar panels that were installed in the 21st century showed the lowest degradation rate at a mere 0.36 percent per year.

Of course, no two solar energy collection and distribution systems are exactly the same, so it’s crucial to have your own panel array and other solar energy components regularly inspected and maintained by a professional.

Other factors that impact solar efficiency over time

Photovoltaic panel arrays that convert light particles into energy are imperative to your sun-powered energy system, but they’re not the only part of a solar power system that are apt to impact efficiency over time. Panels typically last a long time, but other parts may need replacing prior to the end of a system’s projected lifespan. Other components to monitor and maintain include:

1. Electrical inverter

The electricity collected by your solar panels is direct current, or DC. Incompatible with the American power grid, DC energy must first be converted into usable alternating current, or AC, power and passed through a fuse box before it can power your appliances, run your electronic devices, light your home, and reduce your personal dependence on the utility company grid.

Think of the inverter as the brain behind your solar power system. When functioning properly, the inverter acts as the ‘middleman’ between your house and the utility company grid. This grid-tie feature provides an uninterrupted power supply on sunny days with full solar power, at night when you might need full utility company power, and any time your home requires a mix of both.

There are several types of solar system inverters, including relatively inexpensive string inverters and more complex micro-inverters that individually connect each solar panel to the inverter. Power optimizer inverters that comprise both string- and micro-inverters are also available for residential solar consumers.

Inverters also keep an eagle eye on the voltage and power output of your solar panel array and may provide diagnostic info if and when something goes wrong. No matter what sort of inverter your system happens to employ, regular inspection and professional maintenance of your electrical inverter will ensure its efficiency and longevity.

2. Wiring

Equally as important to the operation of your solar energy system are the wires. Although there are no moving parts, wires that connect the panel array to each other and to your home can be damaged by wind, weather, and animals. There is no reason to experience a sudden power failure due to bad wiring when you can hire a professional solar company to perform routine maintenance and scheduled inspections.

Another sort of wiring associated with a home solar energy system is the wires that facilitate the flow of electricity from the panels to the inverter and from the inverter into your home. Due to the dangerous nature of household electricity, all inspection of electrical wires should be done by a licensed professional.

3. Physical supports

Solar panels are typically mounted on a sunny section roof by way of stanchions, bolts, aluminum rails, and retaining clips. Similar supports are employed in ground-mounted panels. Regular inspection and routine maintenance of such supporting structures goes a long way toward ensuring a long productive life for your self-sustaining home energy grid.

4. Batteries

Generating your own clean, green energy is only one of the benefits offered by a modern PV power system. With one or more solar batteries, you can reserve electricity to use at night, during power grid blackouts, or on not-so-sunny days. Solar batteries boost your energy independence and can save you a lot of money, too.

Battery storage capability is expressed in kilowatt-hours (kWh). Smaller batteries may hold around five kWh while bigger batteries may boast a capacity of up to 20 kWh. Solar batteries can stand alone or they may be linked together to provide as much electrical storage as your household requires.

Many utility companies base prices on time of day. If you live in an area where such metering is in place, a solar battery array can provide plentiful power during peak utility company hours. The more batteries you have connected to your personally owned solar energy system, the less you are forced to rely on planet-harming energy sources like oil and coal. A bountiful battery array also gives you a chance to spend money on things other than your local public utility provider.

As with other components of your photovoltaic power system, the batteries should be monitored and maintained at regular intervals. Due to the high voltage electricity generated by the system and stored in the batteries, such monitoring and maintenance should only be done by a qualified solar professional.

If you don’t have solar batteries in place, and your panels generate more electricity than you can use in a day, you may be able to sell your excess power back to your utility provider. Contact your local utility company to find out if they have a buyback program.

Is there any way to improve solar panel life expectancy?

Although the average life expectancy of a modern solar system is at least 25 years, they can last a lot longer if you do one simple thing:

Keep your panels clean

A monthly rinsing can loosen and remove pollen, dust, bird droppings, leaves, and other things that impede the perfect operation of your solar collection panels.

If you think a little bit of dirt on your panels can’t make much of a difference, do think again. Fog and pollen-laden rainwater can pool on your panels then dry to leave behind a muddy residue. Your eyes might not notice it, but your photovoltaic panels sure do. In fact, a single year’s buildup can reduce solar panel efficiency by 5 percent or more.

Of all the debris mentioned above, dust is the easiest to rinse away, while bird droppings may be the most notorious sun-blockers to befall a PV panel. Be patient, and try a directed spray from your garden hose to dislodge debris. If you can’t spray your panels from the ground, schedule a professional panel cleaning.

  • Check the manufacturer’s instructions before cleaning your panels
  • Clean panels early in the day or in late afternoon
  • Never apply cold water to a hot panel
  • Never use a power washer on your solar panels
  • Never use solvents or harsh cleaners on your panels

Enroll in a maintenance and solar service program

Monthly sprays with your garden hose will help your solar collectors last longer, but that’s not the only sort of system maintenance that needs to be done on a regular basis if you want your PV system to live up to its full potential. If you spot inconsistencies in your electrical output, or if you see a flashing indicator light telling you it’s time for a system checkup, contact a qualified solar professional without delay.

Not only can a skilled solar tech remove leaves, pollen, bird residue, and other debris from your panels and restore their ability to collect more rays, they will address every aspect of the inverter, supports, wiring, and other solar system components in which you invested so wisely.

Look for a robust service plan that includes:

  • Performance monitoring in real-time
  • On-site visits to your location
  • Comprehensive pest protection
  • Electrical system checks
  • Solar panel cleaning
  • Solar inverter maintenance

Key Takeaways

  • With an average lifespan of 25 to 50 years, solar panels are a worthy investment
  • Understanding the degradation rate of your panels helps you plan for the future
  • Periodic inspection by a solar professional prevents avoidable solar panel failure
  • Regular maintenance may exponentially extend the life of your solar panels

Thousands of households make the switch to clean, sustainable solar power every year. Even homes that are not able to completely replace utility company power with solar energy enjoy lowered electric bills as well as a sense that they’re doing the planet a favor.

The future of renewable energy is here, and solar is leading the way.


1. National Renewable Energy Laboratory; Photovoltaic Degradation Rates — An Analytical Review

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