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Solar Panel Efficiency: What are the most efficient solar panels in 2020 and what you need to know?

Updated: Jan 29, 2021

What is solar panel efficiency and what is the most efficient solar panel in 2020
Solar Panel Efficiency

When people think of solar energy, the first thing that comes to mind is solar panels. When deciding what solar panels are the right panels for your home, many different factors come into play. Aesthetics, manufacturer reputation, and of course, price point are all important when deciding on what panel to pick.

It does not matter if they are in sunshine rich state like California or Hawaii or an emerging solar market, one factor that can be overlooked but is important is efficiency. Efficiency is a calculation of how much power a solar panel will convert from sunlight. It is a good number to have in mind when comparing solar panels.

Key points on solar panel efficiency:

  • Solar panel efficiency has improved across the industry

  • The highest efficiency for a commercially available residential solar panel is around 23%

  • Many solar panel manufacturers are pushing to make the most efficient panel, but right now the market leaders are LG, SunPower, and REC Solar

  • High-Efficiency solar panels do come with a premium price point

  • If you would like to learn more about panel efficiency and if a high-efficiency panel is the right panel for you, schedule a free consultation with Alchemy Solar

Solar panel efficiency: what is essential to understand? 

Solar panels work by converting sun rays into electricity that can be used at a home or business. The measurement of the solar panel's ability to convert sunlight is known as efficiency. If you placed two different solar panels in the same conditions (direction, mounting angle, orientation, etc.), the more efficient panel would be able to produce more electricity than a less efficient panel. 

The efficiency of a solar panel starts at the solar cell level. The most efficient solar panels have high-efficiency solar cells designed to maximize the production of electricity. In addition to the solar cell, other solar panel components like the wiring, back sheet, and electrical connecting are all factors that can impact the efficiency of a solar panel. 

When looking at different aspects of a solar energy system efficiency can sometimes be overlooked. In reality, it can be one of the most important factors because it can directly impact the ROI of a solar energy system. 

Why Does Solar Panel Efficiency Matter? 

Sometimes when people are discussing solar panels, they can become obsessive about efficiency. As mentioned above, efficiency is only one factor that should be considered when deciding on a solar panel. So homeowners are clear on the impact that solar panel efficiency has. Let's look at the two main reasons solar panels efficiency matters.

Better Payback

If a panel is more efficient, it will produce more electricity. If a system is producing more electricity, the homeowner will need to purchase less from the utility, and as a result, the solar system will save more money.

While efficiency alone does not dictate the panels' performance, a higher efficiency panel can be expected to produce more electricity over the twenty-five plus years the panels are working.

More Power From A Smaller Area

On a quart foot basis, higher efficiency panels produce more electricity. As a result, they require less space to provide the same amount of electricity as a lower efficiency panel. This is why higher efficiency panels make so much sense when a homeowner has limited roof space.

How efficient are solar panels?

As a result of the improvements around solar cell technology, panel efficiency across the solar industry has increased significantly over the past five years. In 2020 the efficiency of most solar panels is between 15% and 20% efficiency. The highest efficiency solar panels are now around 23% efficiency!

To put it into perspective, five years ago, a standard solar panel was rated at about 250 watts, now most standard solar panels are around 320 watts! 

What factors determine solar panel efficiency?

A variety of factors determines solar panel efficiency. At its simplest, efficiency is based on the amount of sunlight that a solar panel can turn into energy. Every aspect of the design and components of the solar panels impact the efficiency of the panels. Let's take a look at the most important ones:

Solar Cells- Solar cells are the part of the solar panel where the conversion of sun rays are transformed into electricity using the solar effect. For most home solar panels, the solar cells are made of silicone and come in two forms: monocrystalline or polycrystalline.

Monocrystalline (Mono, as it is known in the solar industry) solar cells are made from a single crystal of silicon. Polycrystalline (Poly, as it is known in the solar sector) is made from silicon fragments melted down. Because Mono Solar Sells come from one pure silicon crystal, they are usually more refined and, as a result, more efficient at producing electricity. 

Wiring and busing – The solar cells are connected with wiring and busbars. The wiring and busbars allow the electricity to move from the solar cells and out of the solar panel. The organization of wires and the number of "busbars" on a solar panel impact efficiency. Panels with more efficient wiring and more busbars will usually be more productive. 

Reflection – Light reflects off of everything that it hits. By utilizing a particular glass layer on top of the solar cells, it keeps the cells protected and helps focus as much energy from the sunlight on the solar cell.

Backsheet- The solar cells are placed on top of something called a backsheet. Backsheets are usually white or black. Although some people feel that black back sheets are attractive aesthetically, black back sheets absorb more heat and, as a result, leads to slightly less efficiency when compared to a white backsheet. 

What are the most efficient solar panels of 2020:

The most efficient solar panels' list changes rapidly, but based on the information available, the highest efficiency solar panels currently available in 2020 are produced by:

  1. SunPower - 22.8 %

  2. LG - 21.7 %

  3. REC - 21.7 %

  4. Panasonic - 20.3 %

  5. Solaria - 20.2 %

Cost vs. Value

When discussing efficiency, it is essential to remember that the higher efficiency panels come at a cost. The higher efficiency panels are more expensive and, as a result, can impact the Return On Investment of a solar panel system. When examining the higher price point, it is vital to consider things like roof space, electricity production over the life of the solar energy system, and the panel's manufacturer reputation. 


Lots of different factors go into deciding what the right solar panel for your home is. Understanding how solar panels work and what solar panel efficiency means are the first steps towards deciding on the right solar energy system for your home. Solar efficiency has improved over the last decade and has improved, but it is essential to understand that the highest efficiency solar panels usually also have the highest price point. 

If you are interested in learning more about panel efficiency and finding out if they are the right fit for your home, please reach out to Alchemy Solar today for a free consultation. 

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