Solar panels are a great long term investment which saves you a lot of money over its lifetime. But, many people ask how long exactly is this lifetime, how long can you expect those savings to last for. This is important in calculating your ROI on solar panels, especially when going for higher quality models with a greater up front cost.  

So, how long do solar panels tend to last?

Solar panel warranties

First up, a good place to look at when it comes to the potential lifespan of your solar panels is the warranty. Typical warranties for solar panels are 25 years, so you can expect your panels to last at least that long. While over this time they are rated at a particular performance decrease which is stated in the warranty. 80% is the industry standard, this means the panels will still operate at an 80% efficiency rating by the end of the 25 year warranty. So, you can use this rating when calculating your overall ROI. Of course, most panels will out last their warranties, and higher quality panels like those from REA Solar will have a smaller performance decrease over time.   

But how long do the panels really last?

While the warranty is a good place to start it does not tell the full picture. After those 25 years your panels are still operating at 80% efficiency, and for most people’s energy needs this could still be more than enough. The average yearly degradation, according to a 2012 study by the National Renewable Energy Laboratory in the United States, is between 0.5% to 0.8% per year. This could give you another 30 to 40 years if your panels were providing you double your power needs when new.

Solar panels have no moving parts within them. This makes them extremely reliable, boosting their lifespan.     

What does this mean for your ROI?

The majority of ROI calculators for solar panels that you will find online only calculate to a 25-year lifespan. This means that any extra years your solar panels work for is a bonus. Of course we can’t guarantee that your panels will last beyond 25 years but 4 in 5 do. So, once you have paid off your panels, all savings made are going straight into your pocket.  

How to extend the life of your solar system

For your entire system the solar panels will be the most resilient element. For most high quality panels they simply need a wash down with a hose in order to clear any debris. Inverters and batteries, which have far shorter life spans, are what will need replacing. Batteries require maintenance to ensure they are running optimally, and inverters have a shorter lifespan.

Replace the inverters after 10 years

It is safe to assumer you will replace your inverter at least once in the warranty lifespan of your panels. Most standard warranties are at 10 years for inverters, so, if given the option, take the extended warranty for your inverter. This way if your inverter fails 15 years in to ownership you can replace it with a newer and better model.

Cheaper inverters will likely fail more often. So, it is a better idea to not go for a cheaper inverter in order to reduce the amount of times it will need to be replaced.

Maintain and replace batteries

Batteries require a lot more maintenance than solar panels. Due to their more complex nature a lack of maintenance can permanently damage your batteries, even for lower upkeep type batteries like lithium and sealed lead acid.

For example, lead acid batteries often need to be fully recharged after use. If they sit too long without being recharged they can suffer from permanent damage.

Most high-quality batteries will last between 5-15 years depending on the type of battery and how well they are maintained. You can extend the lifespan of your batteries by ensuring you care for them properly and making sure they are installed correctly.

Account for efficiency loss

While your panels will likely last a very long time, your energy consumption may change. This means the most important thing to factor into your calculations is efficiency loss over time. Be sure to consider your own energy usage changes into the future as well. It is often a good idea to get a larger system in order to make up for any efficiency losses and increases in energy usage.