With the move to more eco-friendly living, I receive many inquiries about solar system components and unraveling solar jargon. The most common questions asked are what monocrystalline and polycrystalline solar panels are and their differences.
Monocrystalline solar panels’ efficiency exceeds that of polycrystalline. Mono panels cost more than poly panels, but fewer mono panels are needed to meet your energy needs. If roof space is ample, poly panels may well be your choice. Aesthetically, mono solar panels are black, and polys are blue.
There are some distinct differences between mono and poly solar panels. The following will clarify the differences in an easy-to-read summary.
Monocrystalline Vs. Polycrystalline Differences
Monocrystalline and polycrystalline are the most commonly used solar panels in the solar industry. The terms mono and poly are abbreviations of the above that are frequently used
The core of any solar panel is Crystalline Silicon, the semiconducting material used to make photovoltaic cells. The individual cells are connected and ultimately form the solar panel. The number of cells connected determines the solar panel’s output.
Monocrystalline Solar panels are generally black; the photovoltaic cells are cut from a single crystalline silicon ingot. This means that the consistency and purity of the photovoltaic cells will be better than those used in poly panels.
Polycrystalline cells are manufactured from multiple smaller pieces of silicon that are smelted together to form a solar cell. Poly panels are easy to identify as they are blue.
The manufacturing process of poly panels is more straightforward than that of mono panels; thus, the price per panel is lower than monocrystalline solar panels.
Monocrystalline solar panels photovoltaic cells are more efficient at collecting and converting useable sunlight (irradiation) to electricity due to the higher clarity or purity of the silicon crystal contained in the photovoltaic cells of the solar panel.
Mono solar panels can convert between fifteen and twenty-two percent sunlight to electrical energy. Polycrystalline solar panels’ efficiency ranges between twelve and sixteen percent.
Solar Panel Efficiency Explained
When buying solar panels for your system, one of the most important considerations is the panel’s efficiency rating.
Solar panel efficiency (expressed as a percentage) rates the solar panels’ ability to convert available iridescence (sunlight) that falls onto the solar panels’ surface into electricity.
The best solar panels can reach efficiency ratings of twenty-two percent versus some solar panel ratings that are around sixteen percent.
The solar panels’ efficiency is affected by the quality of the silicon used to make the photovoltaic cells, the quality of the solar panels’ electrical components, and the clarity of the glass covering the solar panel.
The efficiency rating directly impacts the number of solar panels you need on your roof. The theory is that by installing more efficient solar panels, you’ll need fewer solar panels to generate your required energy needs.
Higher efficiency solar panels cost more than lower efficiency solar panels if calculated per watt output, but needing fewer panels may well lead to a saving in the end.
Houses with intricate roof designs or small roofs will benefit from utilizing high-efficiency solar panels due to the saving in roof space required to mount fewer solar panels.
Are Mono Or Poly Solar Panels Better For Your Home?
A few factors have to be considered when deciding between mono or poly solar panels for your home.
These include the following:
- Irradiance
- Temperature
- Roof space
- Orientation of the roof
- Shading
- Dust and grime
- Seasonal effects
- The cost of mono vs. poly panels
Let’s go through each of these in more detail so you can make the best decision for your situation.
1. Irradiance As A Factor When Choosing Solar Panels
Solar panels naturally need sunlight, or specifically irradiance, to generate electricity. Some regions of the world are very well suited to solar energy production due to having long sunny days throughout the year. Unfortunately, some places on earth are not very well suited to solar power generation as the sun just doesn’t shine much.
The correct positioning of your solar panels needs to be calculated, both in terms of orientation and angle. Even though the sun might shine more often than not, the correct placement of the solar panels will ensure that you reap the most benefit out of your solar system.
Regarding solar panel choice, the efficiency between the mono and poly solar panels for home use will hardly be noticeable. In hot climates, even less so. The mono panels would be the better choice for commercial use due to the slightly higher efficiency.
2. Temperature As A Factor When Selecting Solar Panels
Heat, believe it or not, plays a significant role in determining the efficiency of solar panels. Contrary to popular belief, heat does not equal good solar energy production. The hotter the solar panel itself gets, the less productive the solar panel becomes.
The best solar energy production occurs on cool sunny days as the internal resistance of the solar panel’s electrical components is at its lowest when the solar panel is cold. The hotter the solar panel and its electrical components become, the more the resistance increases, and the efficiency drops.
The temperature coefficient measures the loss in efficiency. Reputable solar panels show the temperature coefficient rating on the label of the solar panel.
Most solar panels have a coefficient of 0.35% / degree C. This means the efficiency drops by 0.35% for every one degree Celsius that solar panel heats up above 25 degrees Celsius (77 degrees Fahrenheit), which is the industry standard test temperature.
Monocrystalline solar panels are more efficient and less affected by heat than polycrystalline solar panels. They are therefore the preferred choice for use in sweltering climates.
3. Consider Your Roof Space When Choosing Solar Panels
Roof space can be a real problem when installing solar panels. Some systems may require as many as twenty-four or more solar panels to run a home effectively. When installed, one solar panel of approximately 330-watt rating will require about 21 square feet of space.
Choosing highly efficient solar panels to reduce the number of solar panels required would go a long way towards solving this dilemma. Mono solar panels currently take the lead in efficiency; hence the mono panels are the way to go.
4. Orientation Of The Roof As A Factor When Choosing Solar Panels
The orientation or direction that your roof faces is essential to maximize the efficiency of the solar panels. In a perfect setup, the iridescence (sunlight) would strike the solar panel at precisely ninety degrees.
As the earth is round and constantly turning, permanently mounted solar panels performance is compromised. In the Northern hemisphere, solar panels generally face south. In the Southern hemisphere, the solar panels usually face north.
The best solar conditions occur around the equatorial regions and weaken as you approach the poles.
Polycrystalline solar panels will work perfectly in sunny places with ample sunlight year-round. Should you, however, be in a sunlight-scarce area, monocrystalline solar panels would be best.
5. Shading As A Consideration When Selecting Solar Panels
Shading or shade falling onto the solar panels should be avoided. Shade reduces the efficiency of solar panels significantly. This includes anything such as a building, flag pole, trees, etc. The shadows also move with the sun, so be aware of these when selecting the solar panel mounting position.
In areas where shading is unavoidable, higher efficiency mono panels are recommended to take full advantage of the sunlight when available.
6. Dust and Grime As A Factor When Selecting Solar Panels
Solar panels rely on iridescence (sunlight) to generate electricity. When a layer of debris or something lands on the solar panel, the efficiency of the solar panel is compromised. Dust, grime, snow, and leaves significantly reduce solar panels’ efficiency.
In dusty areas, you would need the most efficient solar panels possible to compensate for the losses resulting from the grimy panel surface. Mono panels would, of course, be your preferred choice.
7. Seasonal Effects On Solar Efficiency
Solar systems are more efficient and generate more solar power in the summer months than in the winter months. The daylight hours are generally less during the winter, which negatively affects the solar system’s ability to match the power generated in the summer.
For the northeastern United States, the annual solar generation is divided into roughly 65 percent being generated between March and September while about 35 percent is generated during the colder half of the year.
The three factors that cause low seasonal solar output are:
- Fewer daylight hours: Shorter sunny days in winter.
- Climate: More cloudy and stormy days in winter and the liklihood of snow covering the panels.
- The sun’s angle: The sun’s angle is lower relative to the angle of the solar panels; hence, less iridescence landing on the panels at 90 degrees.
8. The Cost Of Mono Versus Poly Solar Panels
Mono solar panels cost on average twenty percent more than poly panels in the United States. On the other hand, the mono panels are about twenty percent more efficient, meaning you need fewer solar panels. The cost would be about the same.
Monocrystalline Versus Polycrystalline Efficiency Table
The chart below indicates the maximum efficiency of the average solar panel types arranged from most to least efficient.
As you can see, technological advances have increased the efficiency of the traditional mono and poly panels, with the N-Type mono panels delivering the best efficiency currently.
Before rushing off and buying the biggest and the best solar panels for your home, discuss your needs with your local solar supplier or installer, as some installations will only require a basic solar panel to get the job done well.
| Solar Panel Description | Maximum Efficiency Rating (%) |
| Monocrystalline N-Type IBC | 22.6% |
| Monocrystalline N-Type HJT | 21.7% |
| Monocrystalline N-Type | 20.5% |
| Monocrystalline PERC | 20.0% |
| Polycrystalline PERC | 19.5% |
| Monocrystalline | 19.0% |
| Polycrystalline | 18.0% |
Abbreviations:
IBC = Interdigitated back contact.
HJT = Heterojunction technology.
N-Type = Negatively charged cells – electrons flow from the base of the cell to the top.
PERC = Modified conventional cell generating up to 12% more energy than the equivalent non-PERC solar panels.
How Long Do Mono And Poly Solar Panels Last?
Solar panels are designed and made to last for a long time. Manufacturers don’t have much control over the end destination of the solar panels. As such, solar panels are designed and built to survive extreme heat and cold and everything in between.
Good news for the end-user as most companies offer warranties ranging up to 25 years. Realistically most solar panels can last for up to 40 years. The warranty is usually split into two parts. One covers the physical solar panel. The second part of the warranty usually guarantees at least 80 percent linear output after 25 years.
The linear output warranty means the solar panel will generate at least 80 percent of its advertised output rating when the warranty expires.
Both mono and poly solar panels carry similar warranties and guarantees.
Environmental Impact Of Mono Vs Poly Manufacture
Both mono and poly solar panels utilize crystalline silicon as the semiconductor to generate electricity. Silicone occurs in abundance within the earth’s crust, which means it has to be mined to retrieve the raw silicone from the crust.
Monocrystalline solar panels generate more waste material and consume more energy during the manufacturing process than poly solar panels. As we know, mono photovoltaic cells are cut from a single silicon ingot, resulting in more of the material wasted as only the highest quality raw materials are used.
The Poly solar panels manufacturing process is more efficient than is the case with mono solar panels. Less energy is consumed and required during the manufacturing process, but the raw materials must still be mined.
Solar panels, of course, generate energy from an abundant source, sunlight. Given that a solar panel can last for up to 40 years, generating “free” power, the environmental harm caused during the manufacturing process is offset by the good the panels do during their extensive lifespan.
Conclusion
Monocrystalline solar panels offer better efficiency than polycrystalline solar panels. Mono solar panels are black, while the poly panels are blue. Poly solar panels often also show a flake or scale-type finish on the surface.
Mono solar panels are more expensive than poly solar panels; however, the higher efficiency of the mono panels makes it possible to have fewer solar panels, which saves cost. Poly solar panels are a viable option if you have sufficient roof space as they cost less than mono solar panels but are less efficient. More solar panels are therefore needed to achieve the desired output.