If you’re considering installing solar panels on your home, you know that they harness the sun’s clean, renewable energy to help you cut your electrical bills.
Everyone loves the sound of that!
Furthermore, in addition to cutting your energy costs, they lower your environmental footprint.
Yet, there’s one pervasive question that people often wonder about when installing their solar panels.
Do they work on cloudy days?
Or are they only beneficial when the sun is shining?
Keep reading our solar panel guide to learn how solar panels operate on cloudy days.
1. How do solar panels work on cloudy days?
Most people think solar panels work best when there is direct sunlight, and they’re correct.
However, photovoltaic (PV) solar panels can also use indirect sunlight, such as the kind of sunlight occurring on cloudy days, to generate electrical power.
Although they will be less efficient, they’ll still soak up some sunlight and generate electrical power as a result.
This electrical power will be diminished to some capacity when the light is reflected or partially obstructed by clouds.
On days with heavy cloud coverage, solar panels generate 10 percent to 25 percent of their normal output.
If the clouds happen to bring rain, then this can also be beneficial to your solar panels.
Rain helps to wash away dirt and dust that has gathered on your solar panels.
When your solar panels are clean and clear, they can more efficiently absorb sunlight.
2. How do solar panels work at night?
While solar panels still absorb some sunlight during cloudy days, they won’t work at all during nighttime.
This is because their solar cells aren’t being activated by sunlight and do not generate an electrical current.
Without light, the photovoltaic effect is not triggered, and no power is generated.
The best way you can tell if your solar panels are working is to look at public lights like streetlamps.
If the streetlamps are off, then your solar panels should be producing energy.
If they’re lit, then it’s likely too dark outside for your solar system to be working.
3. How is solar energy stored for cloudy days or night use?
The good news is that you can store energy during peak sunlight hours to use on cloudy days or at night.
Here are the optimal storage options:
Solar battery
When you install solar panels at your residential home, you have the option of adding a solar battery.
This allows you to collect any excess electricity, which can be used during hours of suboptimal sun exposure.
“Suboptimal sun exposure” includes nighttime hours and exceptionally cloudy weather.
Batteries may also allow you to run your solar PV system all day long.
That said, there are some drawbacks to battery storage.
You may want to keep the following in mind.
1. A battery is one more item that you’ll need to install.
2. A battery will add to the total cost of your solar system
3. A battery will take up space
4. You’ll likely need more than one battery if you want electricity for more than a handful of hours.
For example, Tesla solar installations require two Powerwall batteries if your system is over 13 kilowatts
Net metering program
A net metering program will enable you to transmit any excess power your system produces into your municipal electric grid.
This allows you to receive credits from your utility company, which can be cashed in to offset electrical costs that you incur on overcast days or at nighttime when you’re not able to power your home using solar energy.
Net metering can be a cost-effective option that significantly lowers your bills.
However, there are some disadvantages to keep in mind if you’re leaning toward this option.
You may not always break even, and you could still end up paying out of pocket for electricity.
Net metering programs are not offered in all areas or by all utility companies.
If this is the route you want to go, you should check before you install your solar panels.
4. When will solar panels perform best?
If you’re considering installing solar panels, you should note that solar panels do not always operate at maximum production.
Solar panels will perform best when the sun is shining fully.
For instance, when clouds are blocking the sun, you will not have the same results as when the sun is shining fully.
Additionally, when there is no available sunlight during nighttime hours, your panels won’t produce any electricity.
You can circumvent this issue by correctly installing your solar system.
As noted above, the key is to find a sufficient storage option that allows you to always power your home.
Here is a cheat sheet on when solar panels usually perfect the best:
Use solar energy when panels are at maximum efficiency
This will typically be between 11 AM and 4 PM daily
Between April and October there are more daylight hours
Increased daylight and more intense sunlight will result in more solar energy being produced
5. How does the orientation of your panels increase solar electricity?
The orientation of your panels can also help optimize solar power.
This includes both energy production and the number of hours your panels are operating at their maximum.
Your solar panel installer will determine the orientation of your panels based on where you live and the architecture of your roof (if your panels are mounted on your roof).
For homes in the United States, most panels are south facing as we are located in the Northern Hemisphere.
Panels may also be angled slightly East or West to increase coverage and optimal generation throughout the day.
Furthermore, some installers will maintain a pitch of at least 10 degrees so panels can self-clean.
For example, leaves or water will fall off the panels when it rains when the panel is set at a slope.
Having the proper orientation for your household can make a significant difference in the long run.
This is one of the reasons it’s important to work with a qualified solar installation company.
6. How long do solar panels last?
Studies done by the National Renewable Energy Laboratory have shown that modern solar panels have a degradation rate of roughly 0.5 percent per year.
While this has decreased in recent years, a panel purchased 20 years ago would be capable of producing roughly 90 percent of the electricity it produced when it was new.
As a result, solar panel manufacturers usually offer warranties of about 25 years or more.
If solar systems are built even better, then the panels may last 30 years or longer.
That said, you can typically expect the average polycrystalline or monocrystalline panel to last between 25 to 30 years.
This depends on a range of factors.
7. What factors affect the lifespan of solar panels?
There are a variety of factors that will impact your system’s lifespan.
These include:
Environmental Factors
1. Thermal cycling: When temperatures fluctuate (especially between day and night), materials will expand and contract accordingly.
These temperature changes are called thermal cycles, and they can put strain between joints and cause slow deterioration.
2. Wind: Wind can help solar panels stay cooler during hot sunny days, and this will help you achieve greater efficiency.
That said, wind can also cause damage to your panels over time.
3. Humidity: If the temperature is hot and humid in your region, then the moisture and ambient temperature from the environment may lead to electrochemical reactions that can result in corrosion and electrical deterioration.
Humidity can also cause the adhesive to fail in particularly cheap panels.
4. UV Damage: Most solar panels are treated with a protective UV blocker to limit the effects of UV degradation.
However, some cheaper panels aren’t given this treatment and begin to discolor.
As a result, they’ll fall apart as their glue degrades.
Panel Quality
You want to make sure you select the right brand and that each panel is reliable and efficient.
Having high-quality panels will ensure that they are made to last.
On the other hand, cheaply made panels will suffer from substandard materials and construction.
While you may save a few bucks initially, you’ll end up paying for it down the road.
Your panels may need more maintenance, and they won’t last as long.
Installation
Hiring a reputable installer is one of the best ways to ensure your panels are well-connected and installed properly.
A reputable installer will specialize in solar PV systems, and they should be in operation for at least a few years.
When working with a company you trust, you can feel confident in their guidance about the best solar panel system to suit your specific needs as well as the location to place them.
Maintenance
Maintaining your solar panels properly will help them to last longer.
This means conducting regular inspections on your solar panels that can pinpoint potential issues like loose racking, exposed wires, and other areas of concern before they become a bigger problem.
Keep in mind that a solar panel inspection may also extend to an inspection of other solar equipment like inverters or a roof racking system.
While solar panels may last between 25-30 years, typical central inverters for a PV installation will last only 10 to 15 years, which means they will need to be replaced sometime during the life of your solar panels.
8. How can you slow the degradation of your solar panels?
We’ve listed many of the ways that solar panels degrade above.
However, there’s one large way that you can slow degradation in your solar panels, and it starts before they’re even installed.
DON’T CUT CORNERS.
Too many people want to install solar panels on their residential homes, but they try to do so with low-quality products and labor.
Doing this will lead to faster degradation.
Instead, find a reputable solar installer and spend money upfront on a higher quality product.
Additionally, once you’ve installed your high-quality solar panels, make sure you maintain them according to the manufacturer’s instructions.
Although solar panels don’t typically need too much care, a little bit of maintenance can go a long way!
Be sure to remove debris that may get caught in them and keep your panels clean.
9. What’s the right time to replace solar panels?
Knowing when to replace your solar panels depends on many factors.
There’s no strict rule on when you should replace them.
While you may hear the 25-to-30-year rule, we recommend replacing them based on their productivity rather than their age.
When they drop down to an efficiency of below 80 percent (during peak sun), you should replace them.
10. What’s the best way to use solar power at your home?
If you’ve already installed solar panels on your home, here are some tips to help you maximize your usage.
Use electricity generated by solar panels when they are at their peak power output
Utilize energy during the day when your panels are generating electricity
Switch to energy-efficient lights, fittings, and appliances
Use appliances with timers
Manage heating and cooling
Charge your devices during the day
11. Should you install solar panels?
Solar panels are a major investment, which can cause people to wonder, “Are they really worth it?”
However, their cost is declining, and most property owners will break even on their solar investment in seven to eight years.
Whether it’s worth it for you to go solar will depend on a few factors:
How much you pay for electricity
How large your system will be
How much equipment you’ll require
What your roof’s characteristics are
How much labor you’ll require
Where you’re located
What rebates and incentives are available to you (check out the investment tax credit that’s available to everyone)
How you choose to pay (while there are loan and lease options, paying cash will help you save the most of any option)
Final Thoughts
Even on cloudy days, your solar panels can collect indirect sunlight to generate electricity.
Living in a place where it’s not always sunny is not necessarily a good reason to forego solar energy.
Consider installing solar panels today!
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Disclaimer: we are not lawyers, accountants or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.
Prior to starting Gokce Capital, Erika received a Bachelor of Architecture from the University of Southern California and a graduate degree in Urban Policy from Columbia University. She worked as both an architectural designer and engineer in New York before joining the New York City Department of Housing Preservation and Development.
Erika currently lives in the New York Metropolitan area with her spouse, daughter and cat. She is originally from Chicago and still considers herself a midwesterner at heart.
Erika also loves to read, write and travel (fun fact, she has visited all 50 states and more than 30 countries!). Her new book, Land Investing Mistakes: 11 True Stories You Need To Know Before Buying Land, is now available on Amazon.