How to compare solar panels

Solar panels are the main part of your solar energy system, turning the sunlight into energy that your home can use. Solar panels can vary widely, with different sizes, performance, and quality standards. If you’re looking for the right solar panels for your home system, you will need to understand what sets them apart from each other. Solar panels can be compared in many different ways, although their specifications can provide the clearest way.

Solar Panel Specifications:

The specifications listed on the datasheets of solar panels will give a lot of information about your solar panels. These can include performance metrics such as PTC Power Rating, Efficiency percentage. Some specifications show a panel’s performance over time and in varying conditions. These are the degradation rate and temperature coefficient. We’ll explain what these specifications mean, and how they relate to a solar panel’s performance and reliability.

PTC Power Ratings

PTC Power Rating is a measurement of a solar panel’s power output in watts. Generally, solar panels are measured using STC (Standard Test Conditions). Although these measurements are done under lab conditions which are unrealistic when considering real-world use. Here in the U.S., the PTC (PVUSA Test Conditions) rating is commonly used, as the way power output is measured is more realistic, and better reflects real-world use. Some states even use PTC ratings to calculate rebates. If your solar panel doesn’t have a PTC rating, a rough way of figuring it out is by taking 10-15% off the STC rating.

solar panels with woker
Solar panels are the main part of your solar energy system, turning the sunlight into energy that your home can use

Module Efficiency

This specification will detail how well your solar panels can convert sunlight into direct current. This amount will be given as a percentage, with most solar panels having about 15-20% efficiency. Any panels over 20% efficiency can be considered as high-efficiency panels. Generally, higher efficiency panels are smaller than less efficient ones. This is important when considering the physical space your solar panels will take up on your property.

Degradation Rate

The performance of your solar panels will degrade over their lifespan. This degradation will generally be seen as a drop in its average performance. Datasheets can detail the degradation rate of a panel with a graph or will note expect percentage degradation in performance. The degradation rate for a quality solar panel should be below 1% each year it operates.

Temperature Coefficient

Temperature affects the performance of your solar panels, just like any electronic device. The performance of your solar panels goes down when the temperature goes up. The effects of temperature on a specific panel are listed as the temperature coefficient. These coefficients are stated as the percentage of the power value / °C. These affected power values can include Power Max (Pmax), Voltage at open circuit (Voc), or Short circuit current (lsc). The lower the coefficient, the better your panels can perform under heat, which is especially important during summers and in hotter climates.

solar panel types

Other ways to compare solar panels

Aside from performance metrics, there are other ways to compare the solar panels that are available on the market:


The manufacturer of a solar panel can give you an idea of the quality and performance of a solar panel. Just like any product a solid, reputable manufacturer will produce a high-quality product that will work as intended. It’s also important when considering warranties on your solar panels in case of failures. They will provide proper customer service and support to make sure you as a customer are well taken care of. Researching manufacturers can help you decide between different brands on offer.

panels on roof
many solar panels


You may also be considering the look of your solar panels, as they will be a part of your property. Solar panels come in different shapes, sizes, and colors. Solar panel colors tend to be either black or dark blue, although new panel colors are becoming available. You can also consider the different case colors that differ from panel colors. The busbars of a solar panel can differ between models and manufacturers. These are the different visual characteristics that differ between solar panels.


Manufacturers will provide warranties on their solar panels. These warranties cover defective panels as well as performance over time. Defective panel warranties can last up to five years of operation. Performance warranties will ensure that your panel performance won’t degrade below a certain level over a certain period. This is generally stated as the peak power output not falling before a specific percentage over how many years. This can also come in the form of an additional higher output warranty for a shorter amount of time, with a higher percentage. These are important when considering the lifespan and maintenance of your solar panels and solar energy system. A properly functioning solar energy system will last you decades.

With all of these points in mind, you should still ask regarding your solar panel options and which ones would be best suited for your needs and budget. As this will directly relate to the performance of your solar energy system and the savings you can net over time. We offer high-quality solar panels brands from reputable manufacturers. We also provide free installation, zero upfront cost, and a service and parts warranty you can trust to be around for the next 25 years.

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