What is a rooftop solar panel?
A solar panel, or photovoltaic (PV) module, is a device that takes the energy from sunlight and converts it into electricity. Photovoltaics are often used to power calculators, watches, street lights, or water heaters.
Solar panels may be used to charge batteries that power homes and other buildings. Your home may one day have its power supply thanks to solar panels. In these situations, solar panels are often called photovoltaic arrays.
A solar panel is sometimes defined more broadly to mean an array of solar PV cells mounted on a supporting structure, generating electricity from sunlight. The term solar array usually refers to a complete, connected group of solar modules.
Rooftop solar panels for home use
Rooftop solar panels for home use are a system that consists of several individual solar PV modules or solar panels. These are usually roof-mounted and arranged in a series to supply an adequate amount of current. These rooftop solar panels can directly power the appliances within your home that you most often use. Also, if you live in a sunny climate, rooftop solar panels can provide a large amount of clean and free power.
Rooftop garden with solar panels
Solar panels are most commonly used for generating electricity, but they can also be used for other things that may not have anything to do with energy. One idea is using solar panels to cover a roof or balcony with a renewable energy source, creating an urban garden. The captured rainwater could irrigate the plants on your rooftop garden, and the solar panels would provide shade and warmth for the plants.
Types of rooftop solar panels
There are several types of solar panels, but the three most common forms used for home rooftop solar power generation are:
Monocrystalline Silicon Solar Panels:
Monocrystalline silicon solar panels are created from a single, pure crystal of silicon which is sliced into wafers. These solar panels offer the highest efficiency and best performance compared to other rooftop solar panels.
Polycrystalline Silicon Solar Panels:
Polycrystalline silicon solar panels encompass a large majority of all solar panels. Their production process involves the casting and forming of molten silicon into large blocks called ingots, which are then cut into thin wafers.
Thin-film Solar Panels:
These solar panels are also known as amorphous photovoltaic modules. They contain no silicon crystal structure at all but instead use a variety of alternative semiconductor materials.
How do rooftop solar panels work?
How do solar panels work step-by-step?
- Sunlight activates the panels – The solar cells are then exposed to direct sunlight, which activates the silicon crystals’ electrons.
- The cells produce electrical current – The solar cells (or PV cells) create electricity by allowing the electrons to flow between silicon plates.
- The electrical energy is converted into usable electricity – A series of inverters transform the direct current (DC) into alternating current (AC), which is then transmitted to an electrical panel in your home.
- The converted electricity powers your home – The electricity produced by solar panels is then used to power everything in your home that requires electric current.
- A net meter measures usage and production – A net meter measure the energy your home consumes and the energy produced by your solar panels. You will still have to pay for what you use from the utility, but the excess energy is fed back into the grid when your solar panels produce more than you use in a given month. This offsets what you owe and will result in a credit on your power bill.
What is net metering, and how does it work?
Solar power system owners are credited for the electricity they add to the grid via net metering. When your solar PV system produces more electricity than you use in your home, the extra electricity flows to your utility’s electric grid. At night or on cloudy days when your solar panels are not producing much electricity, you draw power from the grid as usual, and your meter runs backward. In other words, you’re using the credits from your system during times of day when it is dark out or when you use more electricity than your solar panels produce. This offsets what you owe and will result in a credit on your power bill.
What happens to excess energy?
Any excess electricity that your solar panels produce will return to the grid, and you’ll receive a credit for this on your utility bill. Net metering differs by state and is required in certain states, such as California, but other states do not enforce net metering laws. If your utility does not have a net metering policy or if your system produces more electricity than you need, your utility may pay you for the excess electricity at a wholesale rate instead of the retail rate.
Benefits of rooftop solar panels
Solar power is a clean, abundant energy source that will play a key role in the world’s sustainable energy future. In this section, we will review the pros and cons of rooftop solar panels.
Pros and cons of rooftop solar panels
The primary benefit of using solar energy is that it can be harnessed through rooftop panels. Rooftop solar panels are a great way to harvest the energy from the sun and turn it into electricity.
Pros of solar power:
* Renewable – Solar energy is a renewable resource
* Clean – The emissions associated with generating electricity from the sun compared to other forms of electricity are much lower
* Harness – Solar power can be harvested from a rooftop in a move to reduce our dependence on non-renewable resources, such as fossil fuels and uranium
* Sustainable – Once a system is put in place, solar energy is sustainable for 25 years or longer
Cons of solar power
* Initial cost – The initial costs associated with installing the system can be high, but they are often tax deductible and can eventually pay for themselves through reduced electricity bills over time
* Limited to certain regions – Solar panels only work in areas that receive at least five hours of sun a day, such as Arizona
* Dependence on the weather – Solar panels only produce electricity during the day when it is sunny
* Dependence on utility companies – Rooftop solar panels feed energy back into a household, but if the electrical grid goes down due to storms or other issues, a home using rooftop solar panels will be without power. This issue can be resolved by installing batteries that store energy from the solar panels, but this increases the system cost.
How much do rooftop solar panels cost?
There are two types of costs associated with rooftop solar panels: upfront and in the long run.
The federal Residential Renewable Energy Tax Credit (ITC) allows homeowners who purchase solar energy systems to claim 26% back on their solar energy system. The upfront cost is the amount it will initially cost to buy and install a rooftop solar system. Other benefits, such as state tax credits and rebates, can lower the upfront cost even more.
Down the road, there are also ongoing costs associated with rooftop solar panels that all homeowners should consider before purchasing a system. These include equipment, labor, maintenance, and other fees to ensure the system is operational.
What are the prices of rooftop solar panels?
There is a wide range of rooftop solar panel prices based on how the system is installed and the energy each system produces. The average cost for one 4′ x 8′ solar panel ranges from $69 to $150, while the average cost for a small photovoltaic (PV) residential system without installation ranges between $12,000 and $15,500.
These numbers can increase significantly based on the type of installation, size of the installation, and other factors. The best way to get an accurate solar panel cost estimate for your home is through a free quote comparison.
What is the price for flexible rooftop solar panels?
The price for flexible solar panels varies depending on who makes the panel. These are often expensive because they use first-generation technology, which is less efficient than the more recent panels.
Installing solar panels on a roof costs?
The cost of installing solar panels on a roof will depend on the type of installation. If you choose to hire someone to do it, you can expect to pay between $1 and $2 per watt installed. This is not an easy process and requires special tools and equipment, so that it can be more expensive than other types of installations such as ground solar panels.
How to install rooftop solar panels?
It is essential to understand that installing solar panels on a roof can be more complicated than other installations because every house is different. In general, the process involves:
Designing and planning the installation
Whether you hire someone or do it yourself, this step will determine how much your system costs and how efficient it will be.
Installing racking or the frame that holds the panels
Depending on your design, this step may already be done for you.
Connecting wiring to the inverter
If using a grid-tied system, this step will require an electrician. For off-grid systems, this is done by your installer.
Installing the panels
Your installer will attach the panels to the rack. A homeowner can do this process, but it is advised that you hire a professional who has experience working on roofs.
Completing the final steps
This includes finishing any additional wiring and attaching the inverter.
How to maintain rooftop solar panels?
Maintaining your rooftop solar panels is an essential part of ensuring they are working efficiently. There are simple steps you can take to ensure your system’s health for years to come.
Some of the most important things you can do as a rooftop solar panel owner include:
- Keeping your panels clean from any dirt or grime that may accumulate on them. A dirty panel will only hinder its ability to collect energy and keep it from working at its full potential. It is recommended that you hose off your panels once a month to keep the surface clean. Ammonia-based cleaners should not be used, as they can damage the panel’s finish and hurt its performance.
- Regular inspection of your rooftop solar panels will allow you to make sure that everything is in good working order. If found, these problems will need to be fixed immediately to prevent further damage to the system.
- You should also periodically inspect your roof where the panels are installed, ensuring no dirt or other materials on the surface where they are placed. If you have an elevated structure with your rooftop solar panels, you want to make sure nothing else has been introduced to create more work for the panels.
- Inspecting the inverter is also essential, ensuring that if there are any problems with it, they are taken care of immediately. The inverter connects your panels to your system, so keep an eye out for anything coming loose or disconnected. Cleaning the interior of the inverter will make certain all connections are working correctly and make sure it is working to its total capacity.
- Keep all wires well protected, ensuring they are not exposed or lying in areas where they can be broken or damaged. The inverter should also have a soft surface below it so that if something accidentally falls onto the unit, there is no risk of damaging it. This will keep your system working correctly and efficiently.
- The last thing you should ensure is that the inverter has enough ventilation around it to keep it cool and work at its best ability, without any overheating problems.
These are just a few of the steps you can take as a solar panel owner to help maintain your rooftop systems. By keeping your panels clean and well-maintained, you will be able to extend the life of these systems.
How to clean rooftop solar panels?
Keeping your solar panels clean is an essential part of ensuring they continue to work correctly. Many homeowners have been concerned about cleaning the panels without drastically reducing their efficiency or hurting their performance.
- One option is to hire a professional cleaning service to come in and take care of the dirty work for you. Most roofing companies also do commercial and residential solar panel window cleaning services, which is a great way to keep your panels clean without harming their performance.
- A second option for solar panel cleaning is to use vinegar or ammonia cleaner on the surface without harming it or taking any of its power away. Even though experts recommend these cleaners, you should test them on a small panel area before using them on the entire rooftop to see if they cause any damage.
- Using a soft brush and water to scrub the panels is another option, making sure you do not use anything abrasive or too harsh when cleaning, as it will reduce their efficiency. You may also want to invest in a squeegee attached to a telescopic rod so you can clean the solar panels from a ladder.
- You might also try using a car-washing solution with no wax or additives, as this will work well to remove dirt and grime without harming the panel’s surface.
Make sure that no matter what method you use, do not spray it directly on the panel; instead, spray it on a soft cloth soaked in the solution and then wipe the panel clean. This will keep the solar panels clean and reduce the amount of time spent cleaning them.
Replacing a roof with solar panels
As most people are aware, there are many benefits to using solar panels on your rooftop. These systems can save you money by producing clean electricity that is cheaper for the home. As more homeowners invest in these systems, some decide to replace their roofs with new solar paneling.
- If you are thinking about replacing your roof with solar panels, it is recommended that you contact a contractor who is experienced in this area. The contractor will tell you what your best options are and help get the process started.
- If you decide to use solar panels made up of photovoltaic cells, you will need to make sure the roof is well-positioned for optimal sun exposure. Since most PV cells are black, they work best when there is not much shading in the area.
- If you choose to use thin-film cells, they can be shingled on a variety of roofs. If you have asphalt shingles, the film cells will be placed on top of them, and the energy will be transferred through the shingles.
There is another option for thin-film cells, and that is to use them as tiles directly on the roof. If you choose this option, it is recommended that you use an adhesive to secure them in place, reducing their risk of blowing away or damaging them.
Roof replacement solar panels tax credit
If you decide to replace your roof with solar panels to get more energy in your home, you may be able to get a special tax credit for this expense. The federal government has programs that will give you up to 26% of the total cost involved in replacing your roof with solar panels so that you can save a substantial amount of money.
The life expectancy of rooftop solar panels
How long do solar panels last?
The life expectancy of a solar panel is at least 25 years, and many manufacturers offer warranties that guarantee 80% or more of the panels’ original output after 10 to 25 years.
If your solar panels aren’t past their warranty period, there’s typically no way to predict precisely when they’ll stop working. The only thing you can do is monitor the system’s performance and have an electrician check it if something seems wrong. However, you should expect a sharp decline in output after about 25 years.
Standard warranties on solar panels
The typical guarantee period for solar panels is 10-25 years. Some manufacturers offer an assurance that enables you to expect 80% of original output after 25 years; you may need to spend more on higher-end models for that level of long-term protection.
Each manufacturer’s warranty varies, so read your warranties carefully. Remember that an 80% or 90% warranty means you should expect a 20-30% decrease in power output after 25 years of use.
The solar panel degradation rate
Unless you install your panels in a particularly harsh environment, they’ll probably degrade by only about 1% to 2% per year. Panels produce less power as they grow older for three main reasons:
* Their output decreases from the moment you start using them.
* They generate less electricity when it’s cold outside because cold air has a more difficult time holding onto electrons.
* Solar panels are more efficient at higher temperatures, but they stop working altogether above about 50°C (122°F).
How to extend the lifespan of the solar panels
By implementing the following ideas, you can significantly extend the life of your solar panels. Good installation and maintenance procedures can add decades to their existence. To get the most extended life from your panels, do these things:
1. Keep them clean
Dust accumulates on solar panel surfaces continuously. If you live in an area that sees lots of wind or rain, you’ll probably need to clean your panels at least once a year.
If panels remain dirty for too long, they won’t absorb as much sunlight and produce as much electricity. You can use a standard garden hose or pressure washer to clean your panels but do so only when the water is less than 50°C (122°F).
2. Keep them cool
High heat can permanently damage solar panels, so you’ll need to take precautions to keep them cool. If possible, orient the panels, so they face away from the mid-day sun around the summer solstice. Tilt the panels to a steeper angle to reflect more light and heat away from them if you can’t do that. You can also shade the panels with deciduous trees or awnings during the summer.
3. Use a microinverter
Solar panels contain DC-to-AC inverters, which change the direct current produced by the panels into alternating current that feeds into the power grid. If you’re building a new solar system, it’s usually best to use microinverters — instead of one large central inverter — on each solar panel. This allows you to place the panels at different angles, which maximizes their exposure to sunlight.
4. Match your inverter to your battery system
Before you invest in a solar panel system, it’s essential to research what types of batteries are compatible with it. Solar panels produce DC power, while most batteries store and deliver energy in the form of AC. If you use an inverter that’s not compatible with your battery system, your batteries won’t last as long as they should.
5. Use higher-quality inverters
Like any other piece of electronic equipment, solar panel inverters carry a certain amount of risk for failure. Investing in inverters with a lower per-watt cost but higher reliability can save you money in the long run.
6. Take good care of your battery system
If your battery system is improperly installed or maintained, it can reduce the lifespan of all your other solar power equipment too. Before installing any batteries, read up on safe installation practices. If you’re not well-versed in battery maintenance, consider hiring a professional.
7. Evaluate performance over time
As solar panels grow older, their output will decrease for the reasons mentioned above — the constant decrease of overall power production and the aging process itself. Panel output can reduce by about one percent to two percent for each year of use, depending on location and how much shade the panels receive. To save money on your utility bills, you’ll need to closely monitor the performance of your solar panels and replace them before they’ve lost too much capacity.