Best solar panels in 2021

monocrystalline solar panels on a grey roof

In this post, learn the best types and brands of solar panels for homes you can install for maximum power generation. The criterion for the list looks at factors such as conversion efficiency, durability, cost among others.

Use of solar panels is a cheaper and eco-friendly way to generate and use electricity.  You can use it in your home and businesses for food processing and preservation, security or outdoor lighting and powering electronic devices and appliances like computers and solar milk coolers. As a result, you can enjoy more efficiency and reduce utility costs, hence getting higher profits.

Over the last decade, there are improvements on photovoltaic technology. It has pushed the cost of a solar panel per watt lower and affordable each year. The other trend is entrance of over 100 solar making companies or brands from China, Germany and the USA giving consumers a wide variety to choose from. Other emerging technologies include Tesla solar roofs and solar windowpanes. With variety comes confusion, this simple guide will help you to settle for the best solar panel for residential use.

Types of solar panels

There are three types of solar panels available for sale in any market today. Monocrystalline, polycrystalline and the thin film solar panels. If you are wondering which one is the best for your home or business, here is a guide on how they are made, cost, efficiency and performance.

Monocrystalline solar panels

Monocrystalline solar panels are the most widely available in the market. If you are looking to install one on your roof top, you are likely to buy this type for its uniqueness. Here are a few quick facts and features about monocrystalline solar panels.

  • Monocrystalline solar panel are made from a single crystalline silicon ingot. The wafers have a unique uniform black color that blend well with different roofing. You can identify then with their black squares with their corners cut off.
  • Monocrystalline panels have the best performance with a high efficiency rating of 17%-22%. Electrons can flow free and fast on the flat mono crystals.
  • They are ideas for people with limited roof spaces. It’s because they have high capacity hence produce higher power output rating than the polycrystalline or thin film modules.
  • They are the most expensive compared to other solar panel types. Its because of their high efficiency and high-power ratings.

Polycrystalline solar panels

Polycrystalline solar panels come with an iconic blue color. They are also known as multi-crystalline solar panels. If you are on a budget and wish to switch to solar, this type of solar panel is the best choice. Here is a summary of a few factors and features of polycrystalline solar panels.

  • Its cells are made of multiple silicon pieces. Their corners are not cut off hence they lack the white spaces as seen on the monocrystalline panels. The multiple crystals give the panes a blue appearance.
  • The polycrystalline solar panels have a medium rating with a power conversion efficiency of 15%-17%.  It’s because the electrons flow is limited in multiple crystals unlike the free flow in the mono crystalline solar panels.
  • They are cheaper to produce and hence relatively cheaper for installers than the monocrystalline panels.

Thin film solar panels

Thin film solar panels are the least installed among the homeowners. They have a wide use in large scale utility, industrial and other specialty projects. They are solid black, light weight and flexible making them easiest to install. Here is a few facts and features about thin film solar panels.

  • Thin file solar panels are made of a thin film of photovoltaic substances like the amorphous silicon or dye sensitized cells deposited on a solid surface like glass.
  • Thin film panels available for sale have extreme low efficiency rating of 10%-13% range. You will need to install more panels than the mono or multi crystalline solar panels.
  • Thin film solar panels are the least durable with the shortest lifespans than the other two types. You will need to replace the panels more often.
  • Thin film solar panels are the cheapest type since they are cheaper to make.  They are not ideal for residential installations where you have limited roofing space.

Best 10 solar brands in 2021

Having understood the comparison of monocrystalline vs polycrystalline vs thin film solar panels above, it’s time to review some of the best solar companies or brands in the market. This review lists them based on efficiency, temperature coefficient, materials warranty.

Solar panel efficiency

Solar panel efficiency is a measure of how it will convert sunlight into electricity power. If a panel is rated 17% efficiency, it means that 17% amount of sunlight hitting its face is converted into electric current.

The following table shows the top-rated Solar panels based on efficiency for standard sizes of 60-cell panels: (39″ x 65″) or the 72-cell panels: (39″ x 77″) monocrystalline commercial solar panels.

Best solar panels by efficiency

RankSolar ManufacturerPanel Efficiency

Solar panel temperature coefficient.

High temperatures reduce the solar panels efficiency. The temperature coefficient is a measure or rate at which your solar panel will underperform with each increase in a degree Celsius (°C). it’s expressed as the percentage decrease in output for every 1-degree Celsius (°C) increase in temperature from 25°C (77°F). Generally, the available monocrystalline solar cells have a temperature coefficient of -0.5%/degC. It is advisable to buy a brand with a lower temperature coefficient to generate high power.

The table below shows the best solar brands by temperature coefficient range.

Solar manufacturerTemperature coefficient range
Q CELLS-0.42 to -0.37
Hyundai-0.45 to -0.41
LG-0.42 to -0.3
SunPower-0.38 to -0.29
Panasonic-0.3 to -0.29

Solar panel warranty

Solar panel warranty is a guarantee or an insurance that your installation will capture its return on investment. Warranty will help you to get service and support needs if a solar panel problem ever occurs during the period. There are 2 types of solar panel warranties that you need to know and consider when you are choosing the best. Product (materials) warrant and the performance warranty.

Product(materials) warranty

The product warranty insurance expresses the integrity of the panel itself and protects you against any problems such as manufacturing defects, environmental issues, premature wear and tear. A longer warranty period is generally more advantageous to you. In your solar panel fails, the manufacturer can ship you a replacement panel and, in some cases, pay for labor costs to replace it.

performance warranty

Most solar manufacturers offer a 10-year product warranty from the date of installation. A solar panel’s performance warranty will typically guarantee a 90% production at 10 years and 80% at 25 years. On the other hand, an equipment warranty will typically guarantee 10-12 years performance without failing.

The table below is a summary of five best solar product and performance warranty for the leading manufactures exporting solar panels globally as of 2019.

Solar panel performance warranty by manufacturer

Solar Panel ManufacturerPerformance warranty guarantee (max)Duration of maximum product warranty
SunPower94%  25 years
LG92.5% 25 years
REC92% 25 years
Panasonic92% 25 years
Solaria86% 25 years

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