Man installing alternative energy photovoltaic solar panels on house roof

Buying a solar energy system is a significant purchase. It is also one of the few home upgrades that will pay for itself in savings. However, the savings from a solar system relies on long-term energy production. If a solar panel or inverter fails, it will decrease the output of the array. Solar warranties protect homeowners from costly repairs and help ensure the system is producing clean energy for decades.

Often, homeowners get two or three proposals for a solar system and then have trouble comparing them without extensive research. Examining the product and labor warranties is one way to differentiate between different bids. Broadly speaking, there are two general types of warranties: for the equipment itself and the labor.

Solar panel warranties

If your solar energy system doesn’t have a battery bank, then the solar panels are likely the most expensive component. Most manufacturers offer two different types of warranties.

Solar panel performance guarantees

Photovoltaic modules are exposed to the elements, day in and day out. As the panels age, they become less efficient in converting sunlight to electricity. Power performance warranties ensure that the solar panels are still producing a certain percentage of their original capacity for a defined period. Many manufacturers offer a guarantee that they will generate at least 90% of their initial output after 10 years and 80% after 25 years.

Solar panel product and materials warranties

These cover the integrity of the solar panels and protect against solar panel defects. Although most major module manufacturers offer equipment warranties for 10 to 12 years, some premium panels have longer warranties.

Which solar panels have the longest warranties?

A few manufacturers set themselves apart by offering long product warranties. LG, Panasonic, Silfab, Solaria, and Sunpower all offer 25-year warranties. Thus, these warranties are often 13 or 15 years longer than other manufacturers, including First Solar, Hanhwa, JA Solar, Jinko Solar, and Trina.

Inverter warranties

An inverter is the brains of the operations, and it converts solar electricity into AC, the current that is used in your home. There are two different types of inverters that are commonly installed for residential projects.

String inverters (or central inverters) are standalone units, and multiple solar panels can feed one inverter. Most residential systems have one or possibly two, and they are usually mounted indoors. When a string inverter fails, the whole solar system could stop generating electricity. String inverter warranties are typically good for between five and 15 years. Some manufacturers, such as SolarEdge, allow homeowners to extend the inverter warranty with an added cost. When installing a string inverter, many systems will also have power optimizers mounted on each panel. SolarEdge offers a 25-year warranty on its power optimizers.

The other commonly used inverter is called a microinverter, and solar systems have one for each panel. Microinverters are mounted on the backside of the module, so they get pretty exposed to the elements. When a microinverter fails, the associated panel will be affected. Microinverter manufacturers often have warranties of up to 25 years, including Enphase.

Solar battery warranties

If your solar system has a lithium-ion battery, it is likely the most expensive component on the solar system. Adding a solar battery to your system could easily add $10,000 to the total system cost. Like the battery in your laptop or cell phone, the capacity slowly decreases over time as the battery is charged and discharged. Most battery manufacturers offer warranties to ensure that the battery is working at a certain level.

The battery warranty ensures that a certain percentage of the battery’s original capacity after a certain period. The Tesla Powerwall comes with a warranty that guarantees 70% of its original capacity after 10 years. Unfortunately, improper installation of a solar battery can void the warranty, so using a skilled solar contractor is essential.

Labor warranties

Although most solar equipment comes with warranties, it often just covers the equipment itself and not the labor associated with swapping it out. Some solar repairs are fairly involved and require technicians going on the roof and removing panels, then mounting and wiring them. Therefore, many solar installation companies provide labor and service warranties.

These warranties vary widely by the installer but often last between three and 10 years. Also, keep in mind that the warranty is only as good as the company providing it. Some installers have only been in business a couple of years and don’t have much of a track record. Consider the reputation of the solar installer when comparing labor and service warranties.

Check your homeowner’s insurance policy

Keep in mind that warranties don’t typically cover damage from intense storms, fires, or other natural disasters. Therefore, make sure your homeowner’s insurance policy covers your installation. Most policies do cover solar systems but confirm with your agent that this is the case for your polity. Also, it might be necessary to increase the policy’s limit to ensure that your new solar system is adequately covered.

By Sarah Lozanova

Sarah Lozanova is an environmental journalist and copywriter and has worked as a consultant to help large corporations become more sustainable. She is the author of Humane Home: Easy Steps for Sustainable & Green Living, and her renewable energy experience includes residential and commercial solar energy installations. She teaches green business classes to graduate students at Unity College and holds an MBA in sustainable management from the Presidio Graduate School.