Solar Panels

The Solar-Estimate expert breakdown of the best solar panels in the industry.

Top Solar Panel Brands

SunPower Overview

Solar-Estimate Review

In terms of pure quality and efficiency, Sunpower solar panels are the best in the industry. Sunpower's X series is the most efficient solar panel in the market with the X22 model providing an impressive 22.7% panel efficiency.

Sunpower provides the best available warranty in the solar panel market. However, a high quality build and high panel efficiency does come at a cost. Sunpower's panels are some of the most expensive in the market, and the panels can only be purchased by a certified solar installer.

Best wattage density, Don't break or crack, lowest degredation

I saw the demonstration of SunPower panels vs traditional panels. A traditional solar cell shatters when flexed and will crack over time from thermal expansion and contraction. The SunPower one does not crack or shatter because it's not ceramic based (it's copper backed). Also, I plan to have these for decades, and the degradation rate is the lowest in the industry. Yes, SunPower costs more, but if you want it to last, SunPower panels are the best. SunPower PVS5 monitoring system with microinverters could be better. It's not bad, but I've seen better.

Review by Jack

Durable, flexible

We were impressed by the flexibility of the SunPower panels, their durability rating is good, and we liked the microinverters on the panels, which give us the ability to expand the system easily if the need arises.

Review by Donna Asher

More reviews for Sunpower
Featured SunPower Solar Panels
Model Watts Efficiency Installed Cost per Watt Details
SPR-X22-370 370 W 22.7% $3.98
SPR-X22-360 360 W 22.2% $3.92

Panasonic Overview

Solar-Estimate Review

Panasonic has made quite a name for themselves as a multinational electronics corporation, and over 40 years of research and development goes into their HIT solar panels. Combine this reputation with their 25-Year 90.76% Limited Power Output Warranty, and you can’t ask for a more reliable solar panel.

The Panasonic HIT series was one of the most commonly used solar panels for residential projects in 2018. Their most efficient panel, the N340 HIT+, boasts a panel efficiency of 20.3%. While Panasonic does not manufacture the most efficient panels in the industry, they have set themselves apart from the competition with their excellent performance in hot weather. The N340 HIT+ has a temperature coefficient of -0.258%/degC which is the most forgiving among the competitors we studied. This means Panasonic panels perform very close to their peak efficiency even in hot climates where other panels struggle to maintain efficiency.

Good warranty, low degradation and temperature coefficient

I bought these panels because the warranty was good, the efficiency was high, and the guaranteed degradation over time was good. The low thermal temperature coefficient also was a positive, as is the fact that they are assembled in the US.

Review by Ecf_in_md

So far so good!

I chose Panasonic based on brand name, warranty duration, but mostly panel specifications compared to those in competing bids. The system only went live ~6 weeks ago, so I cannot give a lot of in-field performance feedback yet. So far all seems to be working as advertised though.

Review by Jacco

More reviews for Panasonic
Featured Panasonic Solar Panels
Model Watts Efficiency Installed Cost per Watt Details
VBHN330SA17 330 W 19.7% $3.37
VBHN325KA03 325 W 19.4% N/A
VBHN340SA17 340 W 20.3% N/A

LG Electronics Overview

Solar-Estimate Review

It’s no secret that LG is one of the world’s leading electronics manufacturers today. Their NeON R series solar panel is one of the most efficient panels on the market with an efficiency of 21.1%. This is the second most efficient panel in our study, behind only the Sunpower X series.

Warranties vary by panel type, with the NeON R series having the best warranty out of the LG models. LG’s warranted degradation rate is not quite as economical as competitors like Sunpower and Panasonic, however LG warranties are still better than most in the industry. LG’s combination of impressive panel efficiency, reputable brand name, and excellent warranty makes it one of our most highly recommended solar panel manufacturers.

Warranty and efficiency.

We liked the LG panels because of the warranty, efficiency and the looks. They were also highly recommenced in the research that we did.

Review by Carlos Acosta

I chose for the look, husband chose for the warranty

Steve did an incredible job explaining all of our different options in solar panel choices (I honestly wasn't even prepared to pick out a solar panel! Didn't know that was even apart of the process! Thank god for Steve!) out of all of the panels that Steve showed us, these definitely LOOKED the best, and that was all that I could focus on from that point. My husband has done his research on panel types and performance on top of the fact that he was dead set on ONLY choosing panels that had a good warranty. Our LG panels have 25 years product and performance warranty which was everything we needed along with the amazing aesthetic as an added bonus!

Review by Lynn B.

More reviews for LG Electronics
Featured LG Electronics Solar Panels
Model Watts Efficiency Installed Cost per Watt Details
LG365Q1C-A5 365 W 21.1% $3.72
LG335N1C-A5 335 W 19.6% $3.47
LG325N1K-A5 325 W 19.0% N/A

Hanwha Q CELLS Overview

Solar-Estimate Review

Founded in 1999, Q-Cells is the youngest solar panel manufacturer in our study. The DUO-G5 is their most efficient model with a 19.6% panel efficiency. Hanwha Q-Cells offers a linear 25 year warranty, guaranteeing at least 85% nominal power up to 25 years. Their best panel, the DUO-G5, has a temperature coefficient of -0.29%/degC which ties for second best in our study with the LG NeON R.

While the Hanwha Q-Cells panels do not rank #1 in the industry for any specific statistics, they are a very reputable, economical, and well-rounded manufacturer. This was enough to land them among our top ranked solar panel manufacturers.

High quality and value

The Hanwha Q CELLS panels are like a premium panel at a standard price point. They have very high energy output and are a at great level of price to performance.

Review by jmarkgraf

Some of the best quality panels for the money

Unless you need the power density of a "premium" panel, you are best served by a brand like Hanwha QCells, that produces top quality equipment, and a 25 year power production guarantee, and at much lower price, so it pays for itself faster.

Review by Jay T

More reviews for Hanwha Q CELLS
Featured Hanwha Q-Cells Solar Panels
Model Watts Efficiency Installed Cost per Watt Details
Q.PEAK DUO-G5 330 330 W 19.6% N/A
Q.PEAK DUO-BLK-G5 320 320 W 19.0% $3.52
Q.PEAK-G4.1 310 310 W 18.6% N/A
Q.PEAK BLK-G4.1 300 300 W 18.0% $3.44

Most Efficient Solar Panels

Solar panel efficiency is defined by the amount of power converted from sunlight to electricity per unit of area. This means that when comparing panels of the same exact size, the more efficient panels will provide more power (in Watts). High efficiency panels tend to be expensive, therefore they are most useful when roof space is limited. Using a high efficiency panel will allow a homeowner to maximize the amount of solar power they can harness given their roof size. This study only includes the best panel from each manufacturer. Otherwise, the top 5 most efficient panels would all be LG and SunPower!

Model Brand Watts Efficiency Installed Cost per Watt Details
SPR-X22-370 SunPower 370 W 22.7% $3.98
LG365Q1C-A5 LG Electronics 365 W 21.1% $3.72
VBHN340SA17 Panasonic 340 W 20.3% N/A
SLA-BC 320 Mono Silfab Solar 320 W 20.0% N/A
Q.PEAK DUO-G5 330 Hanwha Q-Cells 330 W 19.6% N/A

Best Value Solar Panels

The table below ranks panels by lowest median price per Watt from installed residential systems based on publicly available data. This takes into account the total price for the solar system including solar panels, mounting racks, inverters, labor, wiring, and in some cases controllers and batteries. While our rankings should theoretically indicate the most cost effective panel for an overall system, there are many variables which contribute to the cost per Watt. We applied some filters to keep the data as useful as possible. All panels which accounted for less than 0.1% of the total sample size were removed, and the data set is restricted to only residential systems. We are only showing one panel per “product line”. The panel with the best value within each product line takes precedence in this study.

Model Brand Watts Efficiency Installed Cost per Watt Details
VBHN330SA16 Panasonic 330 W 19.7% $2.99
HiS-S355RI Hyundai 355 W 17.1% $2.99
SWA 300 Mono SolarWorld 300 W 17.89% $3.10
LG325N1C-A5 LG Electronics 325 W 19% $3.19
LG295S1C-A5 LG Electronics 295 W 17.2% $3.22

Most Common Panels in 2018

Much of our data comes from solar system data made public by the California Solar Initiative (CSI). Their large sample size of over 130,000 systems in 2018 alone makes this data up-to-date and reliable.

We broke down the most common residential panels into two categories: Third Party Owned and Non-Third Party Owned. Third party owned panels are installed on a homeowner’s house, but due to the contract of a lease/PPA, the value provided by the energy of the panels is owned by a third party, not the homeowner.

Model Brand Watts Efficiency Installed Cost per Watt Details
SPR-X22-360 SunPower 360 W 22.2% $3.92
VBHN330SA16 Panasonic 330 W 19.7% $2.99
SPR-X21-335-BLK SunPower 335 W 21.0% $4.09
MSE295SQ5T Mission Solar 295 W 17.8% $3.57
LG360Q1C-A5 LG Electronics 360 W 20.8% $3.52
Model Brand Watts Efficiency Installed Cost per Watt Details
JKM290M-60B Jinko Solar 290 W 17.7% $3.89
LG320E1K-A5 LG Electronics 320 W 18.7% N/A
JKM295M-60B Jinko Solar 295 W 18.0% $4.17
SPR-X21-335-BLK SunPower 335 W 21.0% $4.09
LR6-60-285M LONGi Solar 285 W 17.4% $3.72
Model Brand Watts Efficiency Installed Cost per Watt Details
SPR-E20-435-COM SunPower 435 W 20.3% N/A
SPR-X21-335-BLK SunPower 335 W 21.0% $4.09
LG400N2W-A5 LG Electronics 400 W 19.3% N/A
SPR-X22-360 SunPower 360 W 22.2% $3.92
CS6U-340M Canadian Solar 340 W 17.5% N/A
Model Brand Watts Efficiency Installed Cost per Watt Details
LG335N1C-A5 LG Electronics 335 W 19.6% $3.47
LG300S1C-A5 LG Electronics 300 W 17.5% $3.33
SW 300 Mono SolarWorld 300 W 17.9% $3.43
SW 295 Mono SolarWorld 295 W 17.6% $4.16
SMX-260P SunSpark 260 W 15.8% N/A

Best DIY Panels

Based on publicly available data in 2018, the average size of a residential solar system was about 7 kW. We compiled a list of solar panel kits closest to this size in an effort to make the fairest comparisons possible. The best DIY grid tied systems are ranked below. Keep in mind that the best system for your home will vary based on your electricity bill. Prices below are from May 2019 and are subject to change. For the most accurate pricing on solar panels based on your location and electricity usage, use the Solar-Estimate calculator.

Model Brand Kit Size Total Price Price per Watt Details
LG365Q1C-A5 LG Electronics 7.3 kW $13,369 $1.83
VBHN330SA17 Panasonic 7.3 kW $11,729 $1.61
MSE315SQ8K Mission Solar 7.56 kW $9,313 $1.23
MSE375SQ9S Mission Solar 7.5 kW $8,769 $1.17
JKM325PP-72-V Jinko Solar 6.7 kW $7,069 $1.06

Solar Panels 101

How Do Solar Panels Work?

Here are the main stages of how a grid-connected solar power system is able to convert sunlight into usable electricity:

  1. Solar cells use light energy from the sun to create an electrical potential. This electrical potential is converted to electricity by attaching conductors to the positive and negative side of the solar cell. Click here for a more scientific explanation.
  2. The electricity created by solar cells is in the form of DC (direct current) power. This power is gathered by all the cells in the panel and sent via conductors (wire) to an inverter.
  3. An inverter converts the DC power into AC (alternating current) power, which is the type of electricity used to power homes.
  4. The AC power coming from the inverter is then connected to the power grid. The solar panels are now providing value to the homeowner by contributing energy to the power grid.

How Many Solar Panels Do I Need?

The number of solar panels required for a home depends on how much energy the home is consuming. Here are the factors which determine how many solar panels are required:

  1. Home electricity usage (in kWh).

  2. The amount of sunlight the panels will get (depends on roof angle, the direction the roof faces, and depends on region).

  3. The amount of power provided per solar panel.

  4. The utility provider. For example, most utilities use net metering. Under net metering, homeowners can typically generate solar at the same cost per kWh that their utility would otherwise charge them.

There are certain circumstances (i.e. net metering with a tiered rate) where you can have a higher internal rate of return (IRR) by offsetting less than 100% of your energy usage. At the end of the day, the number of solar panels you need comes down to your goals and the factors above. To find out your specific needs, use the Solar-Estimate calculator below.


Solar Panels Dictionary

Watts (Power)

Power is the rate of energy production per second. Watts are the units used to describe power output. In this Solar-Estimate study, this metric refers to the amount of power provided by one panel under Standard Testing Conditions (STC).

Number of Cells

Solar panels are made from an array/grid system of solar photovoltaic cells (PV cells). This is the number of cells in the array for each solar panel. The standard size of a PV cell is 156mm by 156mm (approximately 6 in. by 6 in.). The number of cells affects the size of the solar panel. The more cells there are on the panel, the larger the panel size. Panels with more PV cells are typically used for larger systems, as they can provide more power and require less wiring connections.

Type (Monocrystalline vs Polycrystalline)

Monocrystalline and Polycrystalline have different manufacturing processes. Monocrystalline production is an older, more developed manufacturing process. The panels are created from a single continuous cell structure. Monocrystalline panels are generally more efficient than Polycrystalline panels but are more expensive to manufacture. Polycrystalline panels have typically been considered inferior to Monocrystalline due to their lower efficiency. However, as the manufacturing process has evolved over time, Polycrystalline panels can be almost as efficient as Monocrystalline and are much cheaper to produce.

Temperature Coefficient

The key to this measurement is the smaller the temperature coefficient, the better the panel will perform in hot conditions. Click here for a detailed explanation.


"VOC" stands for "Open Circuit Voltage" (the baseline measurement for Voltage). Measured in "Volts", this is the voltage potential between the positive and negative terminal of the solar panel when it is connected to an infinite load (open-circuited). It is the voltage measurement when the electric current is zero.


"ISC" stands for "Short Circuit Current" (the baseline measurement for current). Measured in "Amperes" (or Amps), this is the amount of electric current through the solar panel when the positive and negative terminals of the panel are connected to a load of zero (short-circuited). It is the electric current measurement when the voltage is zero.

Median Installed Price Per Watt

This is the median price per Watt of all residential solar systems in Solar-Estimate’s database. It is the total price of the system including all parts and labor divided by the total power output.


The performance warranties of each panel are best described visually, which is why all warranties are represented by a graph. All performance warranties in our study are classified as "linear performance warranties". We found in our study that many manufacturers compare their linear warranties to a "typical" step down warranty, however we did not find "step down" warranties to be typical at all.

The manufacturers guarantee the solar panels will perform at or above a specified efficiency level for every year throughout the duration of the warranty. If a panel performs below the guaranteed efficiency for any year in the warranty term, the owner of the panel is entitled to a replacement panel at no cost to the owner*.

The best warranty in the market is provided by Sunpower, and we will use this as an example. Sunpower guarantees the X22 series panels will perform at or above 98% for the first year, with only 0.25% per year degradation rate. This means the panel is guaranteed to perform above 97.75% of its initial output after year 2, 97.5% output after year 3, and so on until year 25 where the guaranteed output is 92%. Warranties can also be described by the output level after year 25, rather than specifying the "per year degradation rate". The Sunpower X22 warranty can also be described as a "linear warranty with 98% guaranteed after year 1 and 92% after year 25".

The graph below visualizes the comparison of warranties between the top solar panel brands and a common baseline (in this case the baseline is the Mission Solar MSE295SQ5T).

Warranty Comparison

* If warranties are important to you (they should be!), make sure you read the warranty documentation from the manufacturer prior to making a big purchase. There are many differences between manufacturers regarding what is specifically covered under warranty. As an informed consumer, you will want to know the answer to questions like: "If the panel needs to be replaced under warranty, who pays for shipping and installation?" At Solar-Estimate, we like to keep consumers as educated as possible. The best way to evaluate warranties is to read and fully understand the fine print and details provided by the manufacturer.

Last updated on May 10, 2019 by Scott Nelson

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