Choosing the right solar panels is the first step toward establishing your own solar power system, so obviously it is one of the most important phases of the whole process. If you’re wondering how to compare solar panels, and what are the most important features you should be evaluating, here is a brief guide that will help you in your assessment.
Efficiency, as it relates to solar panels, refers to the panel’s ability to convert sunlight into DC electricity. As efficiency increases with a solar panel, the area required to generate electricity becomes less, so it’s easy to see that a very efficient solar panel will allow you to choose a smaller-sized panel. If there is limited space available to mount your solar panels, this becomes very important, and from the standpoint of resource conservation, smaller and more efficient solar panels are preferred over larger ones.
Rate of Degradation
The rate of degradation measures how quickly over time solar panel output is reduced. For high-quality solar panels, the rate of degradation is often below 1% per year, which means that over a 20 or 30 year period, you could still have a solar panel operating at a very efficient rate, and producing an acceptable level of electricity.
PTC Power Rating
The acronym PTC stands for PVUSA Test Conditions, which refers to solar panel output under typical conditions, and it’s measured in terms of output wattage. The STC rating (Standard Test Conditions), which is what a solar panel’s power output is usually listed at, is tested under laboratory conditions, and therefore less valid than the more realistic PTC power rating.
Most manufacturers provide a warranty with their solar panels, which guarantees that the panel performance will not fall below a specified level of power generation during the period of the warranty. A fairly common warranty calls for power output to remain above 80% for 20 or 25 years. Most warranties also include some period of time where the manufacturer’s parts are guaranteed against defects and workmanship flaws, and this is typically in the range of 5 to 10 years.
It really does matter which manufacturer you choose when researching solar panels, because a manufacturer with a solid background and stable business will be much more likely to honor its warranty on panels. It will also be significant in terms of the level of customer support you can expect, as well as how receptive they are to customer feedback. Also, if you’re a consumer who insists on buying American-made products, you’ll want to check on the manufacturer to keep in line with your preferences.
If you are somewhat sensitive to the aesthetics of solar panels and how they might look mounted on your roof, you should make a point of insisting on a photo of the solar panels in use. Appearance may also be important if there are any local codes or regulations which affect the type of panel which can be used in specific neighborhoods. Learn more about portable solar panels.