The 7 Most Efficient Solar Panels (2023 Guide)

Solar panel efficiency ratings indicate how well solar panels convert sunlight into usable energy. The higher the efficiency, the better the energy conversion and electricity production. Investing in high-quality solar panels with excellent efficiency rates helps maximize your potential energy savings.

Our team invested over 90 hours researching the most efficient solar panels from top panel manufacturers. Along with our top picks, we’ll explain factors that impact panel efficiency and offer guidance on choosing the best options from leading solar panel companies.

• Q Cells: Best Value
• Silfab: Best Power Guarantee
• Canadian Solar: DIY-Friendly Option
• Panasonic: Best Panel for Hot Climates
• REC: Best Durability
• Maxeon (formerly SunPower): Most Energy-Efficient
• Longi: Best Mid-Tier Option

For a full breakdown of the most efficient solar panels on the market, check out the table below.

Solar companies use solar efficiency to measure solar panels’ ability to convert sunlight into usable electricity. Efficiency ratings are expressed as a percentage to help you quickly compare the different panels’ performance. For example, if a solar panel has a 25% efficiency rate, 25% of its captured energy is converted into usable electricity.

Building a solar energy system that operates at a higher efficiency leads to a better return on investment (ROI). Below are several significant reasons to consider optimizing your solar power system for peak performance.

Faster Payback

Solar panels pay for themselves within six to 10 years on average. However, if your panels operate at peak efficiency, you may be able to close that gap faster. More efficient solar panels  have excellent energy production, leading to better savings on electricity bills.

Space Efficiency and Lower Impact of Project

High-quality solar panels offer better efficiency and power production, leading to fewer panels in your installation. Fewer panels also mean less crowding and more roof space. Monocrystalline panels work especially well for homes with limited roof space. Although monocrystalline panels are more expensive, their higher efficiency rate means you’ll cut down on labor and material costs compared to buying less efficient, cheaper solar panels.

A solar panel’s efficiency rate depends mainly on its type. Monocrystalline solar panels are currently the most common, efficient, and cost-effective option for a solar energy system. However, polycrystalline or thin-film solar panels may better fit your home if you have excess roof space or low energy needs. We’ll discuss the different types of solar panels below.

*Average per-watt cost based on wholesale prices (without installation). Cost data from Aurora Solar 

Monocrystalline Panels

Monocrystalline (or mono) panels use a single silicon crystal in their construction. This single crystal provides better sunlight conversion, improving efficiency and energy production. These panels have an all-black appearance, allowing them to blend in better with rooftop designs.

Mono panels come in more compact sizes, making them suitable for homes with limited roof space. They also work well in low-light conditions, which is ideal for cloudy areas. Due to their higher efficiency and production costs, mono panels are pricier than other panel options.

Polycrystalline Panels

Polycrystalline (poly) panels incorporate multiple silicon structures in their design. They have more inconsistencies within the solar cell, resulting in lower efficiency. These panels have a blue hue, making them more visible on rooftop installations. Since they provide lower energy production levels, you’ll need more poly panels to support your energy needs. These panels work best at home with ample roof space and sunlight. Poly panels cost less to manufacture than mono panels, resulting in lower pricing.

Thin-Film Panels

Thin-film solar panels use thin layers of photovoltaic substance in their design, making them more flexible. These panels weigh less than mono and poly varieties but offer the lowest overall efficiency ratings. Thin-film panels have the thinnest construction, making for an easy installation. However, they lack durability and have a shorter life span than other panel options. This is why they’re the least expensive solar panel option.

Most solar installers won’t recommend thin-film panels for your home. They may be incorporated into smaller-scale solar projects, such as a shed or garage.

According to Lawrence Berkeley National Laboratory’s 2022 Tracking the Sun report, average solar panel installations cost between $2.90 and $4.80 per watt. Various factors influence solar panel costs, such as your energy needs, financing options, and available tax incentives. Read on to learn about the main financial factors that impact solar system costs.

• Household electrical demand: Your monthly energy needs impact your solar array size. Homes with mostly gas appliances will use less electricity than those with mostly electric appliances.
• Purchasing options: Paying for your system up-front is the most cost-effective solar financing option because you receive access to tax incentives and avoid additional interest accrual on a loan. Solar loans also qualify you for tax incentives. Solar leases and power purchase agreements (PPAs) offer little to no up-front cost. However, they disqualify you from solar incentives. 
• Solar panel installation cost: The installation price varies by location and solar provider. Cost also depends on your chosen solar panel brand, type, and system upgrades. In most cases, you’ll need to decide between monocrystalline versus polycrystalline panels. Mono panels cost more than poly options. 
• Tax incentives: The federal solar tax credit provides 30% back for solar installation costs. Additional solar tax incentives vary according to state. We recommend using the Database of State Incentives for Renewables & Efficiency (DSIRE) to find all available statewide solar incentives. 

Other physical attributes can impact solar panel efficiency. We’ve listed some of the most significant panel features to look out for below.

Backing

Solar panel backing determines how much sunlight is reflected instead of converted to electricity. The less sunlight a panel reflects, the more efficient it is. Many companies add antireflective coatings to increase efficiency.

Solar Cell Type

A solar cell is a small electrical device that converts sunlight into electricity through the photovoltaic (PV) effect. Most solar cell technology is made from small components called crystalline silicon (c-Si) wafers. Single crystals are used to create monocrystalline silicon solar panels. Multiple crystals are used for polycrystalline panels. When ordered correctly, solar cells from a single crystal have higher efficiency than those pieced together from multiple crystals.

Thin-film solar panels use cells made from amorphous silicon (a-Si). These cells’ atoms are randomly arranged rather than being in an ordered crystalline structure. As a result, they’re less efficient.

Wiring

Improper wiring can significantly impact your solar panel system’s efficiency. Different solar modules may have slightly different electrical and wiring components. A mismatch during installation can lead to performance loss. The same issue can occur if inverters between solar panels are mismatched.

For example, you might buy various monocrystalline panels, but each panel’s design may cause a dip in efficiency if they’re not designed to work together. Getting residential solar panels and inverters from the same manufacturer is always best.

Many environmental factors influence a solar power system’s efficiency. A solar installer will consider these factors when calculating your quote and possible savings. Below are the most significant environmental factors that affect system performance.

Temperature

Typically, solar panels have peak efficiency between 59 degrees Fahrenheit and 95 degrees Fahrenheit. Most panels have standard testing conditions of around 77 degrees Fahrenheit. High temperatures can hinder a panel’s performance. If your solar panels get hotter than 130 degrees Fahrenheit, you may experience a performance drop.

Shading

Obstructions such as trees, hills, and other buildings may create shaded roof areas at different times of the day. How much this affects solar panel power output depends on how long the shading occurs and the shadow size.

Soiling

Soiling refers to the accumulation of debris, such as dust or snow, on your solar panels’ surfaces. This debris reduces the amount of sunlight that reaches the solar cells, causing inefficiency. Although most panels are cleaned naturally by rain, you may need additional cleaning if you live in an area susceptible to dust, snow, or drought.

Weather

Weather and climate play a critical role in your solar energy system’s performance. Regions that are overcast and have more rain and storms are less suited for solar power than regions with clear skies and plenty of sunshine. Although panels are designed to withstand extreme weather conditions, they will impact performance.

Orientation and Angle

The angle of your rooftop and the direction it faces are crucial in determining how optimized your home is for solar power. A south-facing roof is best for solar panels. West and east-facing rooftops also work well but won’t be as efficient. North-facing roofs are often denied for solar panel installation due to their inefficiency.

Additionally, a 30-degree angle is best for year-round solar energy production. Many solar companies will consider an installation if your roof is anywhere between 15–40 degrees, but 30 degrees offers peak performance.

Several influences, such as average energy use, local climate, and roof structure, can affect your future solar panel system. Below are some key factors to consider before installing a solar system.  

• Average energy use and spending: In most cases, solar panels help offset energy costs, reducing your monthly spending. However, that’s not the case for every household. You may not benefit from a solar conversion if your home uses little monthly energy or your electricity rates aren’t high. 
• Buying or leasing: Cash payments and solar loans offer the best financial benefits, such as qualification for solar incentives and rebates. Solar leases and power purchase agreements (PPAs) provide little to no money down and keep panel ownership with the solar provider. Although we recommend buying your system, leasing may be a better option if permanent ownership isn’t right for you. 
• Local weather and climate: Areas with plentiful sunlight benefit most from solar panels. Your panel performance will reduce if your area has frequent cloudy days, rain, or snow. You may need additional solar panels installed to compensate for low-sunlight conditions. 
• Roof space and structural condition: You’ll need ample roof space to house your solar array. Mono panels require fewer modules and less space compared to poly options. You should also check your roof’s structural integrity to ensure it’s in good condition. If your roof needs repair or replacement, you must complete those upgrades before installing a solar system. 
• Surrounding trees and roof shading: Check for nearby shading from trees, tall buildings, or other obstructions that could reduce direct sunlight. Partial shading will reduce energy absorbency, lowering panel efficiency and production. If your property contains too much shading, you may need tree removal services to make your home more viable for solar energy.

Before getting a quote for the most efficient solar panels, there are some important decisions you and your installer must make, such as the number of panels and their roof location.

The video below breaks down those considerations to help prepare you for your quote:

Based on our research, we found that SunPower Maxeon offers the most efficient panels, with ratings close to 23%. You must sign up with SunPower or one of its authorized dealers to use Maxeon panels. As a more cost-effective alternative, consider Q Cells panels. These panels offer high-efficiency ratings at a lower price tag than Maxeon.

Although solar panel efficiency is essential to system performance, other factors, such as available roof space, system costs, home design, and climate, could impact when panels work best for your home. We recommend obtaining quotes from at least three solar installers to compare panel options, including type, brand, and size. 

The This Old House Reviews Team is committed to providing comprehensive and unbiased reviews to our readers. After over a thousand hours of research on solar companies, interviews with experts, and common customer needs, we’ve created a detailed rating system for solar providers based on six factors:

• Solar equipment, installation, and services (25%)
• Warranty and performance guarantees (25%)
• Brand reputation and certifications (15%)
• Financing options (15%)
• Experience (10%)
• Availability (10%)

Total scores are divided by 20 for a final 5-point rating scale.

To share feedback or ask a question about this article, send a note to our Reviews team at reviews@thisoldhousereviews.com.