How to Check Solar Panel Quality (Important Factors)

Are you wondering if the quality of your solar panel is good? If so, keep reading as we help you figure out the answer to that question and some other important information you might need to know. 

In this blog we discuss:

  • What is solar panel quality
  • What solar panel quality means
  • How to check if your solar panel is bad

The choice you make is one that will last for 20+ years, so let’s take a look at the key points and the best solar panels.

Solar Panel Cells High Quality

How do you check solar panel quality?

Regardless of where you install the solar panel — the roof or ground, its quality becomes an essential part of choosing the best solar panel for your property.

So what criterion makes a solar panel great? 

The quality and length of the panels guarantee

If there is a problem or defect, then your first line of defense is the warranty. Remember that a good warranty covers labor, parts, and shipping.

Since most solar panels have a 25-year warranty, the parts and labor portion becomes very important. 

See also: Solar Panels Maintenance: Essential Tips for Optimizing Efficiency and Longevity

Cost efficiency

It pays to look carefully at the cost of the panel per watt of energy produced. Sometimes that is listed. If not, divide the cost of the panel by the number of watts it is rated.

If the panel is $300 and produces 250 watts, then you are paying $1.20 per watt for that panel. That amount is not what you pay for every watt the panel produces.

This tool allows you to see how cost-efficient the panel is compared to the watts it produces. It is a handy tool if you have several panels that are close in features. 

The Technology behind the solar panel or brand

You want to compare apples to apples and oranges to oranges. As you shop for panels, pay attention to the type of panels you find. Some are polycrystalline, and others are mono-crystalline.

You may also find amorphous panels. It is helpful to decide what type of panels you want before comparing brands and panel features. 

The solar panel’s energy efficiency rating

A standard solar panel may have a 12-14 percent efficiency rating, whereas a high-efficiency solar panel may approach 20% efficiency. Efficiency is essential.

It tells you the percentage of sunlight that the panel will capture. If the rating is 19%, the solar panel will capture 19 percent of the sunlight that strikes the panel. If you have shorter days, you probably want higher efficiency.

If you need to create the most power out of a small space, you probably want higher efficiency panels. If you have ten hours of direct sunlight every day, A standard panel may do just fine for you. 

Tolerance of Energy Production

The difference +/- of what a panel can produce. If you have a 200-watt panel with a tolerance of 5 percent, it may produce 195 watts or 205 watts.

A quality panel has a lower tolerance of energy production rating because it will produce closer to its advertised energy production. 

Temperature Coefficient

This is the amount of energy the solar pales drop when at a specific temperature. If the coefficient is high, the panel produces less energy at the rated temperature. A temperature coefficient below 0.5% is good. 

The quality of manufacturing, including the frame and film backing

It is the little things that mean a great deal. If the backing is cheap or damaged, the efficiency of the panel will decay quickly.

If the frame cannot support the glass, then the glass will break or develop micro-fissures. 

The quality and condition of the cables and box

How the solar panel performs can become limited by auxiliary parts, such as the cables, box, or even the inverter. Be sure to check the quality of those parts as part of the overall quality of the panel. 

How do you know if a solar panel is bad?

The efficiency of solar panels degrades over their lifespan. You can check the voltage output and compare that reading to the original output of the panel.

Expect that average degradation is around 1/2 of a percent per year.

If the panel is ten years old, a natural degradation would be 5 percent below its original output. A solar panel that declines more than 10 percent should be replaced.

At 1/2 of a percent decline per year, after 20 years, the panel should still be able to produce 90 percent of its original output. 

What is the best quality of solar panels?

That long list at the top of this article tells us that how you determine “the best” contains a lot of variables. Where you live and how the panel’s installation occurs also play a massive role in creating energy.

Please look at the list we made at the top of this blog and arrange them in the most critical order to you and your situation.

The outcome is very subjective. Keep reading, and we will give you a few of the top brands, and from there, you can check the stats. 

What are the top 5 solar panels?

EcoWatch Ranked the ten best solar panels for 2021: Here’s what they had to say. 

  1. LG — Ranked as one of the best overall solar panels. 
  2. SunPower — is ranked number two due to the high efficiency of its panels. 
  3. Panasonic — Ranked number three due to the high efficiency of their panels during the hottest times of the day. 
  4. SilFab — ranked 4th for offering one of the industry’s more robust warranties. 
  5. Canadian Solar — ranked 5th for being a quality and affordable option for solar panels.

As you go through the top list, be sure to compare the brands to your list of requirements. What is #1 here might not rank at all on your list. 

What is the best solar inverter?

What is the best solar inverter? Well, there are a couple of ways to answer that question. If you are off-grid, microinverters work well.

If you are still grid-tied, you might consider a hybrid inverter, which will handle both DC and AC incoming voltage, making your home electricity needs seamless.

String inverters are a little cheaper to start with, but there can be issues from shading. If you have a battery backup, a hybrid inverter is suitable. 

As you can see, the different types of inverters work differently from each other. But, again, this is a very subjective question, and the answer comes down to your solar needs. 


Photo of author
Elliot has 20+ years of experience in renewable technology, from conservation to efficient living. His passion is to help others achieve independent off-grid living.

SolVoltaics is an affiliate and an Amazon Associate, we earn from qualifying purchases - at no extra cost to you.