ION Solar Blog

What Should You Look For in a Solar Panel?

Finding the right solar panels for your home can mean years of satisfaction while avoiding headaches and additional costs.

With over 300 different companies producing solar panels today, you have a lot of options when considering the panels that are best for your home. Because residential solar panels are an investment spanning 20 to 30 years or more, choosing the right product is vital to the long-term success of your system, the value of your home, and even your own personal peace of mind. What factors weigh most heavily in the quality of a solar panel, and what should you look for when purchasing a solar panel system for your own home? Let’s evaluate together.

How Do Solar Panels Work?

In order to understand which features of a solar panel are most essential to your long-term investment, it is worth examining how solar panels themselves work to generate electricity. 

The use of a negatively charged N-Type layer, and a positively charged P-type layer, allows for the flow of electricity as sunlight pours steadily into the layers of a solar panel.

Solar panels are typically constructed with three distinct layers. The first of these, the “N-Type” layer, is negatively charged with an abundance of electrons. The third layer, or “P-Type” layer, is filled with positively charged atoms called holes. The second layer, the key to igniting the electrical process, gathers light waves from the sun and sends more electrons to the N-Type layer and holes to the P-Type layer. In this state, simply connecting a wire between these layers allows for the flow of electrons and the production of an electrical current.

This is the basis of generating solar electricity, and an effective solar panel must recreate this process constantly over the course of several years. If any part of the process degrades or breaks down, or simply does not function properly, your residential solar panels will underperform or fail.


More efficient solar panels, therefore, are more effective at generating the flow of electrons and converting more of the sun’s rays into electricity. The efficiency of residential solar panels ranges widely, with low-end models featuring about 15% efficiency, and higher-end models functioning at around 22% efficiency. While this may seem like a small difference in output, it constitutes large amounts of electricity for your home over time.

Temperature Coefficient

Heat has a direct effect in limiting an electronic device’s ability to run effectively and produce power.  For solar panels, this is demonstrated through the temperature coefficient, or the decrease in electrical output as the temperature outside rises above 25°C (or 77°F). A solar panel’s temperature coefficient might range anywhere from -0.3% / °C on the low end, to -0.5% / °C on the high end. This means that for every degree above 25°C, the solar panel loses anywhere from 0.3 to 0.5 percent of its efficiency. For this reason, you want a solar panel with a low temperature coefficient rating.


The wattage of a solar panel effectively measures its electrical power output. For standard residential solar panels, this may range anywhere from 250 watts to 400 watts per panel. The wattage of a solar panel is rated in Standard Testing Conditions (STC) of 25°C (or 77°F).  However, due to the temperature coefficient, the wattage may change in actual extreme weather conditions. Capable solar panel wattage should, at a minimum, be 350 watts or above.

Even though they are designed to be exposed to sunlight, all panels face a degradation rating as an effect of weathering and constant radiation.


Like all pieces of electronics, solar panels are subject to degradation and wear and tear over time. Snow, heavy rain, ice, and extreme temperatures all affect the rate at which solar panels lose efficiency, but so too does the nature of simply being exposed constantly to sunlight. A strong solar panel should not degrade at a rate higher than 0.5% per year.


Solar panels feature a product warranty designed to support the homeowner in the case of a defect or malfunction in the panel itself. Solar panels constitute advanced pieces of technology, as well as a significant investment on the part of the homeowner, and so a product warranty geared around protecting your investment is vital.

A solar panel may also come equipped with a performance warranty. Different from the product warranty, the performance warranty is a guarantee that the panel will continue to operate at a certain level of efficiency over time, and not degrade past a certain point. For instance, a performance warranty of 0.5% over thirty years means that the company guarantees that the panels will not have lost more than 15% efficiency at the end of the thirty-year period.

Silfab Solar Panels

When considering all of the above factors, it can be difficult to find a residential panel that rates well in efficiency, temperature coefficient, wattage, and degradation, while also featuring a strong warranty. Among the choices available to homeowners, Silfab Solar panels are a premiere, top-quality choice. Silfab Solar panels feature:

  • A 21.4% efficiency rating. Among the highest in the industry 
  • A temperature coefficient of 0.36%, meaning that they keep more of their efficiency even in non-ideal weather conditions
  • A degradation rate of 0.5%
  • A product warranty of 25 years, and a performance warranty of 30 years (guaranteeing at least 85.1% of the original power performance period at the end of that warranty period)

Let Ion Solar Set You up With Silfab Solar Panels

The professionals at ION Solar sell and install high-quality Silfab Solar panels. These residential solar panels not only look great, but also score among industry leaders in efficiency temperature coefficient, wattage, and degradation value, with one of the industry’s only 30-year performance warranties! Let the professionals at ION Solar help you get the panel that works for you now, and that continues to work for your home in the future. 


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