Efficiency of solar panels: its importance, leading manufacturers, and more

The word “solar panel efficiency” has definitely come up while you’ve been looking at solar panels. Almost all solar panel manufacturers’ websites prominently display the following information: “19% Efficiency!” or “Our highest efficiency solar panel!”

However, what exactly does “solar panel efficiency” mean? Is it the main factor to consider when buying a solar panel? And what influences how effectively a solar panel works in practice?

What is solar panel efficiency?

How much of the sunlight that strikes a solar panel is converted into useful electricity depends on the efficiency rating of the solar panel. More sunlight can be converted into electricity by a solar panel with a greater efficiency rating.

Therefore, a solar panel with a 15% efficiency rating will produce electricity from 15% of the solar energy contained in the sunshine that strikes it.

How efficient are solar panels? 

The majority of solar panels installed today, according to the National Renewable Energy Laboratory (NREL), have efficiency ratings between 16% and 22%, with an average efficiency rating of 19.2%.

Solar panels with efficiency ratings of over 20% are referred to as premium efficiency panels, and they typically cost more. Sunpower, LG Solar, and REC Group are a few well-known manufacturers of superior efficiency panels.

Although 20% might not seem like a lot, solar panel efficiency has increased significantly over the years. One solar panel was only 6% efficient when silicon sun cells were first developed in 1954. The average solar panel’s efficiency was 13.4% just ten years ago. We are now at 19.2%! And with fascinating recent developments like perovskite solar cells, we might even hit 50% efficiency levels!

10 most efficient solar panels of 2022

The following table outlines the 10 most efficient residential solar panels of 2022: 

1SunPowerM Series440 W22.80%
2SunPowerA Series**420 W22.50%
3LG SolarNeON R ACE405 W22.30%
4REC GroupAlpha Pure410 W22.20%
5PanasonicEverVolt380 W21.70%
6Silfab SolarElite380 W21.40%
7Risen EnergyTitan410 W21.30%
8Q CellsQ. Peak Duo Black ML370 W20.60%
9SolariaPowerXT370 W20.50%
10Jinko SolarEagle G4390 W20.43%

*Some commercial solar panels have efficiency ratings higher than those listed; this list is meant to represent high-efficiency residential solar panels. 

**Other Sunpower A-series models, such as the 400 W, 410 W, and 415 W models, have higher efficiencies than other models listed, however, we wanted to show a wider variety of the premium efficiency panels on the market.

How much do high efficiency solar panels cost?

For an 8 kilowatt solar system with high efficiency solar panels, you may anticipate spending between $27,000 and $30,000, before incentives. Comparatively, the upfront cost of the same-sized solar energy system with normal efficiency panels would range between $20,000 and $26,000.

There is no getting around the fact that installing high efficiency panels will cost you more money than installing ordinary efficiency panels. However, more and more solar panel producers, particularly Chinese producers, are releasing panels with efficiency above 20% at considerably more affordable rates.

Today, high-quality panels with efficiency ratings above 20% are available from firms like Trina Solar and LONGi, but they do it at significantly cheaper costs than Sunpower. Although they are presently somewhat more expensive than a normal efficiency panel, if this upward trend continues, high efficiency Chinese solar panels may eventually cost the same as standard panels.

What factors impact solar panel efficiency ratings?

Similar to a layer cake, solar panels are made up of a front glass sheet, an encapsulant layer, solar cells, another layer of encapsulant, a backsheet, and an aluminum frame to hold it all together.

factors impact solar panel

The components used to construct these layers, primarily the solar cells and the backing, have a significant impact on how effectively a solar panel converts sunlight into electricity. These components include:

  • Cell type
  • Busbars and wiring
  • Backing

Let’s take a closer look at each, and how they impact the efficiency of a solar panel. 

Solar cell type 

The type of solar cell employed is one of the main factors affecting the efficiency of solar panels. The component of the solar panel that converts sunlight into electricity is called the solar cell. Polycrystalline, thin-film, and monocrystalline silicon solar cells are the three main varieties.

Monocrystalline solar panels are all you really need to be aware of because they are utilized in practically every solar installation and every high-efficiency solar panel currently available on the market. High efficiency monocrystalline silicon cell varieties include some of the following:

  • PERC solar cells: PERC cells, also known as “passivated emitter and rear contact cells,” typically offer a 1% efficiency boost thanks to a reflective back layer that reflects any light that may have entered the cell from the outside back into it.
  • HJT solar cells: Traditional monocrystalline solar cells have been sandwiched between layers of a new type of silicon that absorbs different wavelengths of light and boosts power output to create heterojunction with intrinsic thin layer solar cells. The use of HJT solar technology is well known among Panasonic and REC Group.
  • Half-cut or Split cells: With split-cell technology, solar cells are literally split in half using a very accurate laser, which lowers heat and resistance while raising total efficiency.

Busbars and wiring 

How effectively solar cells can produce power can also be influenced by how they are linked together. There are numerous thin lines on the surface of solar panels. From the solar cell to the solar inverter, the electricity travels over a network of copper or aluminum cables.

Some solar panel producers are now using multiple, ultra-thin busbars rather than fewer, bulkier busbars, which is known as multi-busbar technology. The solar cell is less shaded and can absorb more sunlight because to the thinner busbars, which boosts efficiency.

IBC, or interdigitated back contact, cells are used by Sunpower, and they have all of their busbars and wiring on the back of the solar cell. As a result, the full cell face may now absorb electricity without being shaded. IBC cells are difficult and expensive to produce, though.


If you’ve ever observed a conventional solar panel, the black solar cells are often bordered by some white space. The backsheet of the panel is that blank area. You may have also seen solar panels with a black backsheet or that are entirely black.

Because it blends smoothly with the color of the solar cells, black backing is a favorite among homeowners because it gives the panels a wonderfully sleek, uniform appearance. However, because black makes the solar panels hotter, they are slightly less effective than ones with white backing. A solar panel might produce less electricity as it becomes hotter.

Do environmental conditions affect a solar panel’s efficiency?

Everything we’ve covered so far has been focused on the efficiency rating of solar panels. Unfortunately, the solar panels on your roof won’t be operating under the perfect conditions required to compute the efficiency rating, which is derived under a specified set of laboratory testing conditions.

This means that the actual efficiency of your panel will rely on a variety of variables, such as:

  • Temperature: The effectiveness of a solar panel decreases when its surface heats up. In fact, sunny, chilly weather is ideal for solar panel operation. Here are further specifics on how temperature impacts solar panels.
  • Solar system orientation: Solar energy systems in the US operate most well on roofs that face south. Other-facing solar panels will receive less sunshine, which will reduce their operating efficiency.
  • Solar system angle: Depending on where you reside, solar panels should ideally be put at an angle between 30° and 45°. The quantity of electricity that solar panels may generate may be reduced if your roof has an extremely steep or shallow pitch.
  • Shading: A solar panel won’t generate as much electricity if it is shaded, such as by the shadow of a tree branch. The production of numerous panels may actually be impacted by shade on one panel, depending on the inverter you have.
  • Weather: Clear, sunny days are ideal for solar panel operation. The amount of electricity the panels produce can be affected by even passing clouds. If you have a lot of snow, you might need to clear them off because it can completely stop energy production.
  • Debris: Your solar panels may become clogged with debris if you live in an area that is frequently burned by wildfires or is very dusty, which will decrease the quantity of sunlight that can be converted into electricity. Solar production can be decreased by even the smallest of things, like bird poop. The majority of the time, rainstorms will take care of clearing anything off your panels, but to maximum electricity generation, you might want to think about cleaning them.

How is solar panel efficiency calculated?

The efficiency rating will be listed on the panel’s datasheet when you browse for solar panels. But how precisely is it determined? The efficiency of solar panels can be calculated using the following simple formula: 

Efficiency = [Power output of panel / (Area of panel x solar irradiance)] x 100

Under Standard Test Conditions (STC), it is presumed that solar panels will experience irradiance levels of 1,000 watts of sunshine per square meter during laboratory testing. With this knowledge, let’s determine the efficiency grade for a:

350-watt panel with an area of 1.8 square meters: 

Efficiency rating = [350 watts / (1.8 m2 x 1,000 watts per m2)] x 100

Efficiency rating = 19.4%

So, this 350-watt panel has an efficiency rating of 19.4%. Not bad!

Do you really need high efficiency solar panels?

The power rating of the panel is what you should actually pay attention to. You can find out from a solar panel’s power rating how much electricity it can generate. It provides you with a clearer overall view of what the solar panel is capable of while also accounting for the panel’s efficiency.

Let’s take an example where you have to choose between two solar panels. Panel A has a 19% efficiency rating, Panel B has a 17% efficiency rating, and both panels have a 350 watt power rating. Since both panels have a 350 watt maximum output, it doesn’t really matter that Panel A has a greater efficiency rating than Panel B. Instead of only choosing the panel with the maximum efficiency, you need also take into account the panel’s price and if that price is reasonable given the benefits it would deliver.

High efficiency solar panels are typically only worthwhile if you have a little amount of roof space and need every solar panel to generate as much power as possible.

The following table lists some of the solar panels we recommend instead of expensive premium efficiency panels: 

ManufacturerModel seriesOutputEfficiency
LG SolarNeON 2335 W19.60%
Q CellsQ. Peak Duo Black350 W19.50%
JA SolarMBB Half-Cell370 W19.90%
Trina SolarResidential Half-Cut Mono PERC365 W19.80%
Jinko SolarEagle 66-TR G4380 W19.91%
REC GroupREC N-Peak 2360 W19.70%
Canadian SolarHiKu Mono PERC360 W19.50%
SolariaPower-XT360 W19.90%
Axitec Solar USAAXIpremium XL HC BLK360 W19.76%
SeraphimS3 Series360 W19.76%

Are premium efficiency solar panels right for you?

Premium efficiency panels are probably not necessary for the majority of homeowners, as we have stated. They are typically more expensive than ordinary efficiency panels and don’t offer many further advantages.

Therefore, you might want to consider a high efficiency panel if you have limited roof space or your roof isn’t oriented well for solar, as they could slightly increase your electricity production. Or, if cost isn’t an issue for you and you simply want the most advanced solar panel system possible, feel free to get those premium efficiency panels!

For everyone else, though, you want to think about which solar modules offer you the best value for your money. You want a solar panel that is cost-effective, dependable, and fits your energy requirements. The Top 10 Best-Selling Solar Panels in 2022 list includes LONGi, LG Solar, and Q. CELLS because they provide a range of solar panels, including high-efficiency ones, that are likely to power your home without costing you an arm and a leg.

Check out our solar panel calculator to get a better understanding of how much money solar panels can save you. From there, you can get in touch with trustworthy local solar installers who can assist you in choosing the best solar panel brand for your roof and start using affordable, sustainable energy to power your home.

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