Do Solar Panels Need Direct Sunlight? No But It Matters (Big Time)

Georgette Kilgore headshot, wearing 8 Billion Trees shirt with forest in the background.Written by Georgette Kilgore

Solar Panels | April 1, 2024

Man holding a solar panel in a shade of a tree wonders do solar panels need direct sunlight, how do solar panels work, and how does solar energy work to create solar power with solar panels in shade?

Do solar panels need direct sunlight to optimize efficient power generation?

The answer is no…but there’s a catch or two.

Solar panels require at least four hours of direct contact with sunlight daily for customers to enjoy maximum efficiency and power generation capabilities. Still, solar panels are scientifically designed to generate power even from indirect sunlight sourcing.

If you live in a region beset with regular cloudy or stormy weather, you should coordinate with a legitimate and professional solar panel contractor to strategize the best angle for solar panels installed on your home or property.

While solar power installation can be costly, depending on where you live, there are numerous municipal, local, state, and federal tax rebates that can help offset costs.2 If you’re considering investing in solar panels, the benefits outweigh the cost for most.

So, do solar panels need direct sunlight? This guide provides everything you need to know.

Do Solar Panels Need Direct Sunlight? (No, But Technically Yes)

No, solar panels can work in indirect light, but it’s better optimally for solar panels to receive direct sunlight exposure for a few hours daily.

It might take longer for solar panels to constantly generate electricity from indirect sunlight.

Every state in the U.S. is ranked for the number of sunlight hours it receives on average, each day, so it’s a good idea to check your state before investing.

On a foggy day, row of houses are illuminated by direct sunlight.

(Image: Winterseitler23)

Depending on whom you ask, solar panels exposed to indirect sunlight may produce 10% to 25% less energy than compared to full sunlight exposure.3

If you live in an area where consistent, direct sunlight exposure is not possible, you still have options. You can invest in solar energy.

You may need to reconsider:

  • Where you place your solar panel arrays
  • Using centralized microinverters to optimize power and guarantee power generation via individual panels
  • Storing excess energy
  • Selling excess energy to local or federal utility companies

The most important question to ask may be, “how many solar panels do I need?” While exposure to direct sunlight is always best, the more solar panel arrays you own, the more you can relatively compensate when drawing power from indirect sunlight.

But for a better informational context, let’s first briefly talk about the sun, how it generates power, and how solar panels collect energy from it.

Do Solar Panels Need Direct Sunlight? (Solar Energy Basics)

To properly answer the question, “Do solar panels need direct sunlight?” you must first understand how sunlight is generated in the sun, what it is, and how it is converted into electricity via solar panels.

How Does the Sun Produce Energy?

The sun is a white dwarf-class star and the largest celestial body in our local solar system.4 It is probably over 4.5 billion years old.

The star is a mass of nuclear explosions, which produce light and heat energy.

A close-up photograph of a solar panel's surface hit by direct sunlight, capturing the reflection of the blue sky above.

(Image: Jniittymaa024)

It takes sunlight over eight minutes and 20 seconds to leave the sun’s corona and reach Earth.5

This is an amazing fact when considering that the sun is over 93 million miles away from Earth’s position.

Another amazing fact to consider is that the sun is not, “burning,” in the same way something burns on Earth. The sun is a giant, gaseous ball of nuclear fire and plasma.

It generates heat and sunlight through nuclear fusion.

The sun’s gravity is so intense that it forces atoms of hydrogen to violently collide and then fuse, which causes nuclear fusion.

The intense heat at the center of the sun is also a crucial component in this process, the sun’s core can be as hot as over 27 million degrees Fahrenheit. This violent fusion causes the two hydrogen atoms to convert into helium.

The process then creates intense heat, energy, and solar radiation,6 which is also known as photons or, “sunlight.”.

How Does Solar Energy Work?

The sun is so bright because there is so much nuclear fusion occurring.

Photon atoms are so densely clustered in the center of the sun that it can take over 100,000 years before those photons, or sunlight, escape the sun’s core and to its corona.

Then, it takes a mere 8 minutes for that sunlight to reach Earth.

Image that shows how the sun produces energy to Earth while showing its components such as deuterium, tritium, neutron, and helium.

In the cold vacuum of outer space, sunlight is also known as solar radiation, and it flows through the vacuum of outer space almost like the wind.

When sunlight finally reaches Earth, it can be converted into useful forms of energy like heat or electricity.

So, do solar panels need sunlight directly?

How Do Solar Panels Work?

Photons, which is just a fancy word for sunlight, do not have any appreciable mass. Energy is measured in denominational units called “joules.”

One photon has less than 10 to 19 joules of usable energy.7 A “watt,” is the number of joules of energy expended via an electrical device per second.

Solar panel set and angled towards the sun, with the bright and intense sunlight shining down on its surface.

(Image: SayCheeeeeese25)

The average American home expends over 10,600 kWh of energy monthly.8 Solar panels are efficiently designed to extract as much energy from sunlight as possible to convert into electricity.

A solar panel is a panel array that is comprised of semiconductor cells manufactured from silicone.9 Numerous cells are grouped together to form one solar panel.

As photons pass through the silicone cells of the solar panel, electrons are knocked free from the photons, which in turn generates an electric charge. So, sunlight is then converted into electricity.

The more solar cells that you have, then the more energy you can create via sunlight conversion.

The most common version of a solar panel is called a photovoltaic cell. This is the solar panel type that is generally used by residential homeowners.

It technically converts photons into electrons, or sunlight into energy. The other type of solar panel is known as CSP or “Concentrating Solar Thermal Power Systems.”

A CSP involves placing hundreds or thousands of specialized mirrors on large swathes of land, usually in deserts or remote areas, to strategically reflect and then concentrate photons towards a receiver. The concentrated solar energy is stored and then converted into heat which can then be also converted into electricity.

CSPs are usually used by large corporate interests.

Depending on how many solar panels you install in your home or property and where you live, your solar panel array system could generate anywhere between 250 to 850 kWh of energy annually.10

And that correlates to about 1.5 to 2.4 kWh of electricity per day.11

While you may not be able to generate 100% of your energy needs via solar power right now, you could definitely offset a third to half of your energy cost, depending on your circumstances.

How Much Sunlight Do You Need a Day for Optimal Solar Panel Energy Generation?

A very crucial factor to remember is that your solar panels need at least four hours of direct sunlight exposure for optimum energy conversion and generation.12

Solar panel absorbing sunlight during sunset.

(Image: PixTreats26)

Direct sunlight hours for every state can be found online, which can be used to calculate the number of panels you’ll need to power your home.

What Does Indirect Sunlight Mean?

Solar panels exposed to indirect sunlight will not function as optimally or efficiently as those exposed to direct sunlight.

So, what does indirect sunlight mean?

Indirect sunlight typically refers to cloudy or rainy weather and shading obstructions that prevent solar panels from efficiently absorbing sunlight to then convert it into electricity.

As long as a solar cell is receiving at least four to four and a half hours of direct sunlight exposure daily, it will convert 15% to 20% of its direct sunlight exposure into electricity.13

Experimental scientific advances in renewable energy research are even developing next-gen solar panel arrays that can convert up to 50% of direct sunlight exposure into electricity.

As previously mentioned, solar panels exposed to indirect sunlight can dampen efficiency by 10%, 25%, or even more. “Indirect sunlight exposure,” should mean that ambient sunlight is still available.

Cloudy or rainy weather blocks sunlight from fully reaching the surfaces of solar panels. Improperly placed solar panels that are shaded from sunlight by tree branches or structures also prevent solar panels from fully optimizing their potential.

So, what can be done about this problem?

Do Solar Panels Need Direct Sunlight? (Practical Solutions)

To maintain and enjoy optimal efficiency, solar panels should be exposed to direct sunlight whenever possible for as long as possible. However, solar panels are designed to convert photons into electricity by capturing photon atoms that are present in ambient sunlight, not just from direct sunlight exposure.

This does not mean that your solar panels should be facing a wall or shadows all of the time. What it means is that if the sun is still shining on rainy or cloudy days, even though sunlight is obscured in those situations.

Solar panels in shade will still operate effectively if not as efficiently as those placed in direct sunlight.

Do solar panels work on cloudy days? Yes.

It might take a little longer relatively to produce energy, but solar panels in shade will still function.

Do solar panels work in the rain? Yes, they do – which is sometimes beneficial.

Solar Panels in Shade

Solar panels often become shaded and obscured from efficiently capturing sunlight through dust accumulation.

Rain cleans away dust and helps solar panels operate a little more efficiently, even in indirect sunlight situations.

Modern solar panel technology is a lot more advanced now. So, while it is not ideal for solar panels to be exposed to indirect sunlight, modern solar panels still operate in such conditions.

If you are plagued by indirect sunlight problems, you should make certain that your solar panel array is using the right kind of inverter system.14 The energy generated via solar panel technology is direct current or DC.

The electrical grid systems of Western countries utilize AC or alternating currents, or AC.

Solar panels installed flat on mount absorbing sunlight directly with trees in the background.

(Image: Ecombetz27)

So, a solar panel converter converts solar energy, which is DC, into AC so that you can use it in your home.

A string inverter is kind of like an old-school Christmas lights system – if one malfunctions then every light is compromised. String inverters wire solar panel arrays through a centralized system.

What this means is that if even one solar panel is shaded, then every solar panel in the system with operate less efficiently as well, even though they are not shaded.

Make sure that your solar panels utilize microinverter systems. This means that every solar panel in the array system acts independently.

If one solar panel is shaded or obstructed, the efficiency of the unshaded panels won’t be affected.

How To Install Solar Panels on Roof

Even if you live in a region or area where your roof solar panels are exposed to indirect sunlight, your solar panels should be angled towards the sky in a way that points them directly in the sun’s orbital path in the sky at all times.

Solar panel owners who live in the Northern Hemisphere should have their panels installed pointing at true south, not magnetic south. And the solar panels should be tilted or oriented at the sky at a 30% to 45% angle, depending on your geographic circumstances.15

Circumstances regarding direct or indirect sunlight exposure on solar panels will vary according to geographic location. Knowing how to install solar panels on roof in your location will help maximize the efficiency of your solar panels.

Vet and consult with a local and professional solar panel installation contractor.16 If you live in an area with consistent indirect sunlight issues, a solar panel installer can tell you everything you need to know to optimize your solar energy system.

Do solar panels need direct sunlight? Not necessarily but they need ambient sunlight and to be oriented properly towards the sun in the sky to make such an investment worth it.

DIY Solar Panel Installation

Unless you are properly licensed and trained to do so, solar panel installation must always be performed by a legitimate, fully trained, and licensed contractor. Fully vet and interview local contractors before choosing one.

A solar panel contractor must inspect and survey areas on your home and property to properly install solar panels. There is no “one-size-fits-all” approach when it comes to solar panel installation.

Where you live, the dimensional parameters of your home, and several other factors related to your property will determine what kind of solar panel system will be installed.

Such careful and exacting preparation must be performed to ensure the maximum efficacy of a solar energy system installed on your property.

Carbon Footprint Solar Panels

How much carbon footprint solar panels generate?

Solar panels do not generate any carbon footprint when they are in operation.

However, there is a substantial amount of emissions generated during the materials acquisition, manufacturing, and disposal phase, which means that they do generate emissions.

Facts About Solar Energy: Solar Power Facts

A home equipped with a solar panel system can see its value increase by over $15,000.17

You could potentially save $1,500 annually and up to $33,000 on your energy costs over a lifetime by switching to solar power.18

You can take advantage of tax credits and rebates of up to 30% against your solar panel installation costs.19 But hurry – these tax rebates will decrease or expire between 2024 and 2034 depending on your tax bracket and where you live.

Solar power is a 100% green, renewable, and storable energy source. A controversial April 2021 environmental research report commissioned by Carbon Tracker stated that renewable power sources like solar and wind could overtake fossil fuels as the planet’s primary power source by 2035.1

The controversial study even predicted that renewable energy could entirely obsolete the planet’s fossil fuel infrastructure by 2050 at the earliest.

Ever wondered how many solar panels to power the US? Almost 8 billion.

Thinking about how to get solar panels for free from the government? Anyone promising you such is scamming you.

How much do solar panels cost in your state after considering hidden fees and applicable taxes? It depends on where you live and your tax bracket.

The initial installation and start-up costs for a residential solar panel array system will cost anywhere between $3,500 to $35,000 at the minimum.20

However, the system will pay for itself after taking advantage of applicable tax rebates and using it for 30 or 40 years.

Do solar panels need direct sunlight, no, but you will get better results with direct sunlight so it’s important to know exactly how many daylight hours your area will receive.

Frequently Asked Questions About Do Solar Panels Need Direct Sunlight

How Do Solar Panels Work on a House?

A solar panel contractor will survey your property and determine where exactly to place the solar panels. They may place them on the roof of your or someplace else on the property where it’s determined the panels will receive the greatest amount of direct exposure to sunlight possible.

Do Solar Lights Need Direct Sunlight?

No, but just like solar panels, they operate more effectively with exposure to direct sunlight. Since most solar light products and systems are photovoltaic, they can capture the photons in ambient, indirect light sources to produce energy.

How Many Hours of Sunlight Do Solar Panels Need?

Generally speaking, solar panels need about four hours of direct sunlight every day to operate optimally. However, solar panels will also operate as long as they are exposed to indirect sunlight.

How Are Solar Panels Tested?

If you want to know how to test a solar panel, your best option is to get a contractor to do it or teach you how to do it. Testing solar panels requires an understanding of complex technical specifications to be done properly.21

How Much Is One 100-Watt Solar Panel?

It will cost you anywhere between $100 to $300.

What Will a 100 Watt Solar Panel Run?

To those wondering, what will a 100-watt solar panel run? A 100 Watt solar panel can run small electronic devices such as mobile phones, laptops, small fans, and LED lights.

What Are Solar Shingles?

If you’re torn deciding between solar shingles vs solar panels, then you should know they are the same thing. Solar shingles operate on the same technical premise as solar panels.22

What Do Solar Panel Do?

The first solar panel device is technically the magnifying glass, which was probably invented in the 7th century. A Swiss scientist named Horace de Saussure is probably the first person to invent the prototype inspiration for the modern solar panel way back in 1767.


References

1Vetter, David. (2021, April 26). How Renewables Could Kill Off Fossil Fuel Electricity By 2035: New Report. Forbes. Retrieved April 10, 2023, from <https://www.forbes.com/sites/davidrvetter/2021/04/26/how-renewables-could-kill-off-fossil-fuel-electricity-by-2035-new-report/?sh=20e47bee65ed>

2Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. (2023, March). Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics. Solar Energy Technologies Office. Retrieved April 10, 2023, from <https://www.energy.gov/eere/solar/homeowners-guide-federal-tax-credit-solar-photovoltaics>

3Energy Report. (N.d.). Do Solar Panels Work in Cloudy Weather? Energy Report. Retrieved April 10, 2023, from <https://energyreport.us/do-solar-panels-work-in-cloudy-weather/>

4NASA. (2023, March 22). Sun. Solar System Exploration Our Galactic Neighborhood. Retrieved April 10, 2023, from <https://solarsystem.nasa.gov/solar-system/sun/overview/>

5Cain, Fraser. (2013, April 15). How long does it take sunlight to reach the Earth? Phys.Org. Retrieved April 10, 2023, from <https://phys.org/news/2013-04-sunlight-earth.html>

6Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. (n.d.). Solar Radiation Basics. Solar Energy Technologies Office. Retrieved April 10, 2023, from <https://www.energy.gov/eere/solar/solar-radiation-basics>

7Brown. (n.d.). 4. Energy, Power, and Photons. Brown. Retrieved April 10, 2023, from <https://www.brown.edu/research/labs/mittleman/sites/brown.edu.research.labs.mittleman/files/uploads/lecture04.pdf>

8EIA. (2022, October 12). FREQUENTLY ASKED QUESTIONS (FAQS). U.S. Energy Information Administration. Retrieved April 10, 2023, from <https://www.eia.gov/tools/faqs/faq.php?id=97&t=3>

9Harvey, Alisa and Dhar, Michael. (2022, February 11). How do solar panels work?.Live Science. Retrieved April 10, 2023, from <https://www.livescience.com/41995-how-do-solar-panels-work.html>

10Allen, Nafeesah. (2022, November 21). How Much Power Does A Solar Panel Produce?. Forbes. Retrieved April 10, 2023, from <https://www.forbes.com/home-improvement/solar/how-much-power-does-a-solar-panel-produce/>

11Lane, Catherine. (2023, March 13). How much energy does a solar panel produce?. Solar Reviews. Retrieved April 10, 2023, from <https://www.solarreviews.com/blog/how-much-electricity-does-a-solar-panel-produce>

12Wakefield, Faith. (2023, February 24). How Many Solar Panels Do I Need? MarketWatch. Retrieved April 10, 2023, from <https://www.marketwatch.com/guides/home-improvement/how-many-solar-panels-do-i-need/>

13University of Michigan. (2021). Photovoltaic Energy Factsheet. Center for Sustainable Systems, University of Michigan. Retrieved April 10, 2023, from <https://css.umich.edu/publications/factsheets/energy/photovoltaic-energy-factsheet>

14Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. (n.d.). Solar Integration: Inverters and Grid Services Basics. Solar Energy Technologies Office. Retrieved April 10, 2023, from <https://www.energy.gov/eere/solar/solar-integration-inverters-and-grid-services-basics>

15Brooks, Ashlyn, and Saddler, Lowe. (2022, November 7). What Is The Best Angle And Orientation For Solar Panels? Forbes. Retrieved April 10, 2023, from <https://www.forbes.com/home-improvement/solar/best-angle-for-solar-panels/>

16Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. (n.d.). Homeowner’s Guide to Going Solar. Solar Energy Technologies Office. Retrieved April 10, 2023, from <https://www.energy.gov/eere/solar/homeowners-guide-going-solar>

17Energy Saver. (n.d.). Benefits of Residential Solar Electricity. Energy Saver. Retrieved April 10, 2023, from <https://www.energy.gov/energysaver/benefits-residential-solar-electricity>

18Crail, Chauncey. (2022, October 25). How Much Do Solar Panels Save The Average Homeowner? Forbes. Retrieved April 10, 2023, from <https://www.forbes.com/home-improvement/solar/how-much-solar-panels-save/>

19Washington, Kemberly. (2022, August 19). Here Are 3 Tax Breaks Included In Biden’s Climate Law. Forbes. Retrieved April 10, 2023, from <https://www.forbes.com/advisor/taxes/climate-law-tax-breaks/>

20Brill, Rebecca. (2023, March 16). How Much Do Solar Panels Cost? Forbes. Retrieved April 10, 2023, from <https://www.forbes.com/home-improvement/solar/cost-of-solar-panels/>

21Liter of Flight USA. (n.d.). How To Test Solar Panels Like Pro? – Quick And Easy. Liter of Flight USA. Retrieved April 10, 2023, from <https://www.literoflightusa.org/how-to-test-solar-panels-like-pro-quick-and-easy/>

22Thoubboron, Kerry. (2023, March 9). Solar shingles: what you need to know. Energy Sage. Retrieved April 10, 2023, from <https://news.energysage.com/solar-shingles-vs-solar-panels-whats-the-difference/#solar-shingle-disadvantages>

23Photo by Winterseitler. Pixabay. Retrieved from <https://pixabay.com/photos/village-sunlight-fields-town-2090495/>

24Photo by Jniittymaa0. Pixabay. Retrieved from <https://pixabay.com/photos/solar-panel-sun-electricity-energy-1393880/>

25Exeter High School solar panels, Photo by SayCheeeeeese / CC0 1.0 Universal Public Domain Dedication. Resized and Changed Format. From Wikimedia Commons <https://commons.wikimedia.org/wiki/File:Exeter_High_School_solar_panels2.jpg>

26Photo by PixTreats. Pixabay. Retrieved from <https://pixabay.com/illustrations/solar-energy-power-electricity-sun-7788516/>

27Wolfhagen Barracks Solar Roof, Photo by Ecombetz / Public Domain. Resized and Changed Format. From Wikimedia Commons <https://commons.wikimedia.org/wiki/File:Panzerkaserne_Wolfhagen_Solardach.jpg>