With more than one million individual solar power systems installed and running in the United States, home buyers are increasingly seeing homes with solar panels on the market.
Many homeowners’ introductions to solar energy comes from purchasing a home with panels already installed. However, relatively few will take the time and effort to learn just how efficient their systems are, and even fewer will maximize their solar energy output as a result.
A solar inspection checklist can help you determine the value of your home’s solar panels and ensure that that the panels continue to perform at peak efficiency for decades.
Just How Durable Are Solar Panels?
Solar panels contain no moving parts. This, combined with the strength and durability of modern panel materials, means that your home’s panels should last decades. Most solar lease contracts specify term lengths of at least 15 years, showing that under normal conditions, you should be able to expect solar benefits long-term.
Solar panel designers and engineers know that panels have to be weatherproof, and build panels with weather in mind – even severe hailstorms usually fail to significantly impact panel performance.
When buying a home, you generally don’t have worry about old, broken panels. However, you should visually examine and clean the panels to ensure optimal performance. Snow, pollen, sand, dust, and bird droppings may not ruin your panels, but they will affect their ability to capture sunlight.
If any of the panels are broken, you will have to have a qualified professional replace them. Replacing damaged panel glass is not a DIY project, so don’t let homeowners try to underestimate the costs.
Find Out How Old the Panels Are
Unlike more recent advances like solar panel drone technology, roof-mounted photovoltaic cells benefit from decades of engineering and are largely designed for long-term use. The US Department of Energy’s National Renewable Energy Lab (NREL) has published studies measuring the power output of solar technologies over a 40-year period.
Overall, the lab has found that the durability, performance, and effectiveness of panels has gotten better over time. The main point new homeowners should take from this study is one that agrees with consumers’ intuition – newer panels are worth more than older ones. Having a clear idea of how old your new home’s panels are lets you put an exact figure on their price, which should factor into your real estate negotiations.
Check for Structural Issues
Poorly installed panels are a common problem, particularly for older homes and panel systems. Modern solar panel service companies now have standardized workflows for attaching panels to residential rooftops, but in the past this was not the case.
Mounting damage may not affect your panels’ performance, but it can lead to serious issues with your roof and attic. A quick visual inspection should be enough to tell if you have structural problems. Be on the lookout for leaks and unusual drafts – bad weather can create the perfect conditions for water damage.
Check for Corrosion and Wiring Abnormalities
Photovoltaic cells may contain materials that, if damaged, may corrode over time. Older panel systems with unusual films or discolored surfaces should be replaced. These corroded materials compromise the integrity of the entire solar panel array, and will only get worse over time. Solar panel service companies can address these issues and replace corroded panels quickly.
Wiring abnormalities generally come in two varieties – those you can see and those you cannot. It should be obvious that loose or snapped wires require replacement, but hidden wiring problems are more difficult to diagnose.
Newer systems typically come with some sort of monitoring system – an application, a web portal, or some kind of regular power production tracking tool. With older systems, the only way to identify wiring problems is through certified inspection solar panel service companies offer. A volatile electric bill may indicate that the system’s wiring is not running as consistently as it should.
Understand Solar Panel Degradation
Understandably, new solar panels operate at maximum efficiency. As panels get older, they degrade very gradually – a power generation loss of 0.8% per year is not uncommon. This means that barring any other major issues, a set of 25-year old solar panels will still operate at around 80% efficiency.
If your home’s solar system is that age or older, you will have to take degradation into account when determining how much money the panel will save you on your monthly electric bill. Beyond the 25-year mark, there is no upper limit to how long panels can continue working, but degradation will have an increasingly pronounced effect as time goes on.
If you have questions about your new home’s solar panel system that this solar inspection checklist does not address, a local solar panel service company technician may be able to learn more about your specific set of panels.