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When are Solar Panels Most Effficient

By: Eric Huesca, SEO Content Writer

January 6, 2023

Solar power has been the talk of the town, especially since the issue of climate change has hit the headlines, and for a good reason. There are many ways of producing electricity, but solar power is one of the cheapest and most effective ways to generate electricity, thanks to efficient solar panels.

The sunlight that strikes the earth in 30 minutes is enough to power the entire globe for a full year. Solar panels use photovoltaic cells that absorb the energy coming from sunlight. 

Solar Panels on gorgeous home

Beautiful home with solar panels on each section of the home.

This energy is responsible for knocking electrons out of the atoms and generating free-flowing electric current. Many such photovoltaic cells are joined together to form a solar panel.

What does efficient mean? Can we improve the efficiency of solar panels? We’ll answer all these questions and tell you when efficient solar panels perform their best and which are the most efficient solar panels to buy.

Sunny Days

Direct sunlight is one of the most obvious things that facilitate efficient solar panels giving the desired output. Solar energy is a direct product of the sun, so solar panels need much of it to perform at their peak.

Effect of Excessive Heat on Solar Panels

Solar panels perform better in high sunlight. In normal cases, higher sunlight reflects better output. But, if there is too much heat or humidity, it negatively affects the performance of efficient solar panels. Sunlight excites electrons and puts them in motion from their rest state. The energy difference between the rest and motion is the amount of electricity produced.

If there is too much heat, electrons will already have a lot of energy at rest, reducing the energy difference between their rest and energetic states. Ultimately, this leads to lower output of electricity and reduced efficiency.

Effect of Cloudy Days on Solar Panels

Although solar can work on cloudy days, their efficiency could improve. Usually, efficient solar panels only produce 10-25% of their standard output on days with an average cloud cover. During slightly cloudy days, solar electricity generation can see spikes thanks to the “edge-of-cloud” effect, which results in clouds passing by the sun and their edges magnifying sunlight.

However, the story on heavily overcast days is a bit different. If you can see shadows outside, sunlight is available, and your system might generate electricity. On the other hand, if you cannot see any shadows, the cloud cover is too thick for the sunlight to reach efficient solar panels and produce electricity.
In short, if there’s a sunny day out there, your solar panels are designed to perform exceptionally well. If you couple it with proper cleaning, you can have more efficient solar panels.

After Cleaning Solar Panels

Getting the light to hit your efficient solar panels is essential for producing solar energy. However, dirt, debris, and bird droppings can block that light and prevent it from interacting with the photovoltaic cells properly. No wonder cleaning them properly can improve the efficiency by 7-9% on average, which in some cases can go up to 30% too.

Do Rainwater Clean Solar Panels?

This is a common question that arises in the mind of many solar panel owners. Unfortunately, rain doesn’t clean the solar panels, something regularly demonstrated by your car’s windshield.

Rain contains airborne dust particles that attach to efficient solar panels and stay there when the rainwater evaporates. Therefore, it is crucial to maximize the reach of sunlight to your solar panel.

Some Cleaning Recommendations

  • Make sure you’re safe from electric shocks by cleaning modules when production is at its minimum.
  • Ideally, deionized water or water with less than 75 ppm should be used. Anything above 200 ppm leads to a build-up of scale on the module.

  • Use mild, non-abrasive, and non-caustic detergent for cleaning to avoid any damage.

  • Use a soft sponge, microfiber cloth, or a non-abrasive brush to clean stubborn dirt such as bird droppings, dead insects, tar, etc.

  • Water pressure shouldn’t exceed 35 bars to avoid damaging the module.

  • Cool modules before cleaning to avoid the thermal shock that might lead to cracks. The temperature of the water should also be equivalent to the ambient temperature.

Choosing the Right Solar Panel

Many feel confused when buying efficient solar panels for the first time, as they encounter two main types, monocrystalline solar panels (mono) and polycrystalline solar panels (poly). There are significant differences between them that need to be discussed. It is a debate of effective vs. efficient when both are compared.

Monocrystalline Solar Panels

A single silicon crystal is used to build monocrystalline solar panels, which are shaped into a cylindrical ingot. They have sleeker aesthetics and are usually more efficient because the electrons have more space to move in the single crystal. Therefore, you’ll need fewer panels to produce more electricity than others, a perfect efficiency formula.

Polycrystalline Solar Panels

Instead of using a single silicon crystal, manufacturers melt multiple fragments of silicone to form polycrystalline solar panels, also known as multi-crystalline or many-crystal silicon. Polycrystalline solar panels usually have lower efficiency than their monocrystalline counterparts because of tighter spaces for electrons. However, manufacturing them is easier, so they have lower prices.

Let’s compare different aspects of monocrystalline and polycrystalline solar panels to understand which is better.


When it comes to the efficiency of different types of solar panels, monocrystalline panels take the lead over polycrystalline panels, the most efficient solar panels. Electrons have a much easier path to move in mono panels, which frees them up, and electricity moves much more smoothly inside them. They can reach an efficiency above 23%, while the same number for polycrystalline is below 20%.


Monocrystalline panels cost more than polycrystalline panels, determined by their silicon structures. The cost of the former is higher because its production is a complex process that requires much more care and control. The cost of wiring, labor, racking, etc., is the same for both.

However, monocrystalline is more efficient than solar panels, which might be a better investment in the long run. Moreover, they are more suitable if you have a tight space for placing your panels. Both solar panels are also eligible for the federal solar tax credit.

Aesthetics & Lifespan

The lifespan of both monocrystalline and polycrystalline panels is the same, as the type of silicone cell doesn’t impact life. Both panels have operated efficiently for more than 25 years.

Monocrystalline panels are usually black, while polycrystalline panels have a blue hue.

Temperature Coefficient

The temperature coefficient measures how well a solar panel performs during warm temperatures. Monocrystalline panels are better than polycrystalline panels regarding temperature coefficient. That’s more applicable to areas that experience high temperatures.

If you live in a cooler place, polycrystalline panels are also viable because they won’t heat much.

Personal Preferences

If color is important to you, monocrystalline and polycrystalline panels differ in colors. The former has a darker black color, while the latter has a bluish tint.

Space Constraints

You should use more efficient solar panels if you have limited space on your roof. Paying a bit extra to buy high-efficiency monocrystalline panels will help you maximize your energy production and make more sense in the long run.

However, if you have more space on your roof or are installing ground-mounted solar, lower-efficiency polycrystalline panels can also be a viable choice at a lower cost.

Placement of the Solar Panels

How solar panels are placed plays an important role in their efficiency and electricity production. As a rule, solar panels harness the most sunlight when it hits them perpendicularly. Ensuring that the solar panels are placed appropriately produces the maximum possible power. The time of the day also matters when we discuss power production from solar panels.


If you’re living in the Northern Hemisphere, make sure your solar panel is facing the south most, ensuring they receive the most sunlight. However, before doing that, you should know the difference between magnetic south and actual south. Magnetic south is the south that your compass shows, pointing towards the earth’s magnetic pole.
However, you must ensure your panel faces the geographic south, not the solar one. Similarly, your panel should face the geographic north if you live in the Southern Hemisphere. Also, move and adjust your solar panels as the sun moves in the sky.

For instance, moving it, southwest can help it produce more energy in the evening when the sun is setting. During the evening, the drop in solar energy can be balanced by electricity available from other sources. There is no solar power at night as the moonlight isn’t strong enough to produce any electricity.


The angle at which the solar panel is placed is also crucial for producing the maximum amount of electricity. A general rule is to place the panel at an angle equivalent to geographical latitude.


After reading this guide, you’re well aware of everything that makes efficient solar panels perform at their best. From cleaning them to maximizing the benefits of the best time of the day, make sure you follow all the guidelines to enjoy the immense benefits of solar power.

If you also want to become part of the expanding network of energy-efficient homes, Solgen Power is here to help you out. Our family-friendly policy helps you transition to solar power efficiently and transparently,
powering multiple home appliances.

The Solgen $0 Down Financing helps you go solar without paying any upfront costs. So why wait? Contact us today and contribute towards the green economy while saving tons of money.

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