Solar panel wiring basics: How to string solar panels
Solar panel wiring (also known as stringing), and how to string solar panels together, is a fundamental topic for any solar installer. It’s important to understand how different stringing configurations impact the voltage, current, and power of a solar array so you can select an appropriate inverter for the array and make sure that the system will function effectively.
The stakes are high. If the voltage of your array exceeds the inverter’s maximum, production will be limited by what the inverter can output (and depending on the extent, the inverter’s lifetime may be reduced). If the array voltage is too low for the inverter you’ve chosen, the system will also underproduce because the inverter will not operate until its “start voltage” has been reached. This can also happen if you fail to account for how the shade will affect system voltage throughout the day.
Thankfully, modern solar software can manage this complexity for you. For example, Aurora’s auto-stringing functionality will automatically advise you on whether your string lengths are acceptable, or even string the system for you. If you are looking for a reliable and easy way to map out your solar configuration, Aurora’s auto-stringing functionality enables you to virtually string solar panels.
However, as a solar professional, it’s still important to have an understanding of the rules that guide string sizing. Solar panel wiring is a complicated topic and we won’t delve into all of the details in this article, but whether you’re new to the industry and just learning the principles of solar design. or looking for a refresher, we hope this primer provides a helpful overview of some of the key concepts.
In this article, we’ll review the basic principles of stringing in systems with a string inverter and how to determine how many solar panels to have in a string. We also review different stringing options such as connecting solar panels in series and connecting solar panels in parallel.
Key electrical terms for solar panel wiring
In order to understand the rules of solar panel wiring, it is necessary to understand a few key electrical terms—particularly voltage, current, and power—and how they relate to each other. To understand these concepts, a helpful analogy is to think of electricity like water in a tank. To expand the analogy, having a higher water level is like having a higher voltage – there is more potential for something to happen (current or water flow), as illustrated below.
What is voltage?
Voltage. abbreviated as V and measured in volts. is defined as the difference in electrical charge between two points in a circuit. It is this difference in charge that causes electricity to flow. Voltage is a measure of potential energy, or the potential amount of energy that can be released.
In a solar array, the voltage is affected by a number of factors. First is the amount of sunlight (irradiance) on the array. As you might assume, the more irradiance on the panels, the higher the voltage will be.
Temperature also affects voltage. As the temperature increases, it reduces the amount of energy a panel produces (see our discussion of Temperature Coefficients for a more detailed discussion of this). On a cold sunny day, the voltage of a solar array may be much higher than normal, while on a very hot day, the voltage may be significantly reduced.
What is an electrical current?
Electric current (represented as “I” in equations) is defined as the rate at which the charge is flowing.
In our example above, the water flowing through the pipe out of the tank is comparable to the current in an electrical circuit. Electric current is measured in amps (short for amperes).
What is electric power?
Power (P) is the rate at which energy is transferred. It is equivalent to voltage times current (VI = P) and is measured in Watts (W). In solar PV systems, an important function of the inverter — in addition to converting DC power from the solar array to AC power for use in the home and on the grid — is to maximize the power output of the array by varying the current and voltage.
For a more technical explanation of how current, voltage, and power interact within the context of a solar PV system, check out our article on Maximum Power Point Tracking (MPPT).
In it, we discuss current-voltage (IV) curves (charts that show how the panel output current varies with panel output voltage), and power-voltage curves (which show how panel output power varies with panel output voltage). These curves offer insight into the voltage and current combination(s) at which power output is maximized.
Basic concepts of solar panel wiring (aka stringing)
To have a functional solar PV system, you need to wire the panels together to create an electrical circuit through which current will flow, and you also need to wire the panels to the inverter that will convert the DC power produced by the panels to AC power that can be used in your home and sent to the grid. In the solar industry. This is typically referred to as “stringing” and each series of panels connected together is referred to as a string.
In this article, we’ll be focusing on string inverter (as opposed to microinverters ). Each string inverter has a range of voltages at which it can operate.
Series vs. parallel stringing
There are multiple ways to approach solar panel wiring. One of the key differences to understand is stringing solar panels in series versus stringing solar panels in parallel. These different stringing configurations have different effects on the electrical current and voltage in the circuit.
Connecting solar panels in series
Stringing solar panels in series involves connecting each panel to the next in a line (as illustrated in the left side of the diagram above).
Just like a typical battery that you may be familiar with, solar panels have positive and negative terminals. When stringing in series, the wire from the positive terminal of one solar panel is connected to the negative terminal of the next panel and so on.
When stringing panels in series, each additional panel adds to the total voltage (V) of the string but the current (I) in the string remains the same.
One drawback to stringing in series is that a shaded panel can reduce the current through the entire string. Because the current remains the same through the entire string, the current is reduced to that of the panel with the lowest current.
Connecting solar panels in parallel
Stringing solar panels in parallel (shown in the right side of the diagram above) is a bit more complicated. Rather than connecting the positive terminal of one panel to the negative terminal of the next, when stringing in parallel, the positive terminals of all the panels on the string are connected to one wire and the negative terminals are all connected to another wire.
When stringing panels in parallel, each additional panel increases the current (amperage) of the circuit, however, the voltage of the circuit remains the same (equivalent to the voltage of each panel). Because of this, a benefit of stringing in parallel is that if one panel is heavily shaded, the rest of the panels can operate normally and the current of the entire string will not be reduced.
Information you need when determining how to string solar panels
There are several important pieces of information about your inverter and solar panels that you need before you can determine how to string your solar array.
You’ll need to understand the following inverter specifications ( these can be found in the manufacturer datasheet for the product):
- Maximum DC input voltage (V input, max ): the maximum voltage the inverter can receive
- Minimum or “Start” Voltage (V input, min ): the voltage level necessary for the inverter to operate
- Maximum Input Current: how much energy the inverter can handle before breaking
- How many Maximum Power Point Trackers (MPPTs) does it have?
What are MPPTs?
As noted above, a function of inverters is to maximize power output as the environmental conditions on the panels vary. They do this through Maximum Power Point Trackers (MPPTs) which identify the current and voltage at which power is maximized.
However, for a given MPPT, the conditions on the panels must be relatively consistent or efficiency will be reduced (for instance, differences in shade levels or the orientation of the panels).
It is also important to note that, if the inverter has multiple MPPTs then strings of panels with different conditions can be connected to a separate MPPT.
Solar panel information
In addition to the above information about your selected inverter, you’ll also need the following data on your selected panels:
- Open circuit voltage (V oc ) : the maximum voltage that panel can produce in its no-load condition
- Short circuit current (I sc ): the current running through the cell when the voltage is at zero (although we won’t delve into current calculations in this article)
An important thing to understand about these values is that they are based on the module’s performance in what is called Standard Test Conditions (STC).
STC includes an irradiance of 1000W per square meter and 25 degrees Celsius (~77 degrees F). These specific lab conditions provide consistency in testing but the real-world conditions a PV system experiences may be very different.
As a result, the actual current and voltage of the panels may vary significantly from these values.
You’ll need to adjust your calculations based on the expected minimum and maximum temperatures where the panels will be installed to ensure that your string lengths are appropriate for the conditions the PV system will encounter, as we’ll discuss below.
Basic rules for how to string solar panels
Ensure the minimum and maximum voltage are within the inverter range
Do not allow the strings you are connecting to the inverter to exceed the inverter’s maximum input voltage or maximum current, or to fall below its minimum/start voltage.
Ensure that the maximum voltage complies with code requirements in the area where you are designing.
In the U.S., the National Electrical Code caps the maximum allowable voltage at 600V for most residential systems. In Europe, higher voltages are allowed.
Pro Tip: Don’t use STC values alone to determine voltage range
We know that voltage is additive in series strings while current is additive in parallel strings. As such, you might intuitively assume that you can determine the voltage of our proposed PV system design and whether it falls within the recommended range for the inverter by multiplying the voltage of the panels by the number in a series string. You might also assume that you could determine the current of the system by adding the current of each parallel string (which would be equal to the current of the panels multiplied by the number in the parallel string).
However, as we discussed above, since STC values reflect the modules’ performance under very specific conditions, the actual voltage of the panels in real-world conditions may be quite different.
Thus the simplified calculations taken from STC values only give you an initial rough estimate; you must account for how the voltage of the system will change depending on the temperatures it may experience in the area where it is installed. At colder temperatures, the voltage of the system may be much higher; at higher temperatures, it may be much lower.
To ensure that the temperature-adjusted string voltage is within the input voltage window of the inverter it will require a more complicated formula, like the ones below :
If these equations look a bit like gibberish, don’t worry, Aurora solar design software automatically performs these calculations and alerts you as you are designing if your string lengths are too long or too short given the expected temperatures at the site. (For more information on stringing in Aurora, see this help center article.)
Aurora also performs a variety of other validations to ensure that the system will operate as expected and not violate codes or equipment specifications — this can prevent costly performance issues. (For a detailed overview of these validations see this page in our help center.)
An example of underperforming PV systems
For a real-world example of why it is so important to accurately account for how environmental conditions will impact the voltage of your PV system, read our analysis of an underperforming system in Cathedral City, California. In that case, a solar designer’s failure to account for the presence of shade resulted in the system frequently falling below the inverter’s start voltage and therefore producing significantly less energy than forecasted.
Ensure strings have similar conditions — or connect strings with different conditions to different MPPT ports
Once you’ve determined that your strings are acceptable lengths for the inverter specifications, another key consideration is that the strings have the same conditions (e.g. same azimuth/orientation, same tilt, same irradiance) if they are connected to the same inverter MPPT.
Mismatches in the conditions on the strings will reduce the efficiency and power output of your solar design. For a discussion of why mismatches in shading. orientation, or azimuth result in lost power output see the fourth article in our PV system losses series : Tilt Orientation, Incident Angle Modifier, Environmental Conditions, and Inverter Losses Clipping.
If you are designing for a site where it’s necessary to have panels on different roof faces, or some areas of the array will get more shade than others, you can ensure that the panels with different conditions are separated into their own strings, and then connect those strings to different MPPTs of the inverter (provided your chosen inverter has more than one MPPT).
This will allow the inverter to ensure each string operates at the point where it produces the maximum power.
Advanced considerations to optimize your design
The above rules will ensure that your stringing configuration will comply with the specifications of your inverter and that the energy production of the system won’t be negatively affected by mismatches in the conditions on the panels.
However, there are additional factors that a solar designer can consider to arrive at the optimal design (that is, the design that maximizes energy production while minimizing cost). These factors include inverter clipping, the use of module-level power electronics (MLPE) — devices which include microinverters and DC optimizers, and design efficiency provided by software tools.
Sometimes it may make sense to oversize the solar array that you are connecting to the inverter leading to a theoretical maximum voltage that is slightly higher than the inverter max. This may allow your system to produce more energy (because there are more panels) when it is below its maximum voltage, in exchange for reduced (“clipped”) production during the times when the DC voltage of the array exceeds the inverter’s maximum.
If the production gains exceed the production lost to inverter clipping, then you can produce more power without paying for an additional inverter or one with a higher voltage rating.
Of course, this decision should be made with care and a clear understanding of how much production will be clipped compared to how much additional production will be gained at other times.
In its system loss diagram. Aurora indicates how much energy will be lost to clipping so that you can make an informed decision about whether this makes sense. For a detailed explanation of inverter clipping and when a system with inverter clipping makes sense, see our blog article on the subject.
String inverters are not the only inverter option. Microinverters, which are inverters that are attached to each individual panel (or a couple), allow each panel to operate at its maximum power point regardless of the conditions on other panels. In this arrangement, one need not worry about ensuring panels on the same string have the same conditions. Microinverters can also make it easier to add more panels in the future.
Explore a few different options to find the best one
As you can see, there are many considerations when it comes to stringing your panels and finding the inverter and stringing configuration that is best for the customer.
You may not arrive at the optimal design the first time around so it can be helpful to evaluate a few different options. In order for this to be efficient, however, you’ll need a process where you can evaluate multiple designs quickly. This is where solar software, like Aurora, can be particularly valuable.
Let solar software do the stringing for you
Finally, technology like Aurora’s autostringing functionality can do the stringing for you! It will take into account the considerations discussed here and present you with an ideal stringing configuration.
Schedule a demo to see how software can help you design your solar systems.
- Maximum DC input voltage
- Start voltage
- Maximum input current
- Number of MPPTs
- Open circuit voltage
- Short circuit current
Understanding the principles of solar panel wiring lets you ensure optimal designs for your solar customers. To learn more about how solar works, how to size a solar system, how to mitigate shading losses, and more, check out PV Education 101: A Guide for Solar Installation Professionals.
Schedule a demo to see how software can help you design your solar systems.
Here are a handful of quick answers to frequently asked questions about solar panel wiring basics.
What wiring is required for solar panels?
Solar panels require wiring that is protected for outdoor use and rated to handle the system’s amperage. Most modern solar panel installations use single-conductor Photovoltaic (PV) wire, between 10 and 12 gauge AWG. Wiring is required to connect the solar panels to the charge controller, inverter, and battery (in an off-grid system).
Is it better to wire solar panels in series or parallel?
In terms of power production, it is better to wire solar panels in a parallel circuit rather than a series. Parallel solar wiring allows for more independent power production between the panels but also increases the system’s upfront costs for materials and installation. To maximize electricity production without exceeding inverter voltage ratings, some solar energy systems use a combination of series and parallel wiring connections. Technology such as solar optimizers and microinverters can also help maximize system efficiency.
How many solar panels can I connect to my inverter?
The number of solar panels you can connect to your inverter is identified by its wattage rating. For example, if you have a 5,000 W inverter, you can connect approximately 5,000 watts (or 5 kW) of solar panels. Using 300 W solar panels, you could then connect roughly 17 solar panels (5000 W / 300 W per panel).
Can I connect solar panels directly to a battery?
Although the answer is technically yes, you should never connect a solar panel directly to a battery. As solar power is generated at various intensities throughout the day, charge controllers (or regulators) modify the energy so that it can be efficiently stored in the battery. Using a charge controller between the solar panels and storage bank maximizes the system’s production and protects the battery from overcharging, damages, and malfunctions.
Can I use solar panels and an inverter without a battery?
Yes, as battery technology improves, many homeowners are considering battery storage as an addition to their solar system. But, traditionally, most grid-connected solar systems didn’t have battery storage. While it is impossible to run an off-grid photovoltaic (PV) energy system without battery storage, professionally permitted and installed solar panels and inverters safely produce solar power that is distributed throughout a home and fed into the utility electrical grid.
How long does a solar panel installation take?
One of the first questions homeowners have when they’re thinking about installing home solar panels is “how long will the installation take?”. Believe it or not, the actual installation can take as little as six hours. But, going solar consists of a lot more than just getting contractors up on your roof. There are a few additional factors you need to keep in mind when trying to plan out how and when to complete your installation.
We’ll walk you through the solar installation process and determine how long it may take for your home.
See how much you can save with solar panels
Solar installation timeline at a glance
- The total solar installation process will take somewhere between two and six months to complete.
- Typically, contractors install a residential solar system in as little as 6 hours.
- The longest part of the installation process is waiting for permit approval, which has the potential to take almost two months to complete.
- Once the system is installed, you still need to wait for one to six weeks for your city and utility to inspect and approve the installation.
- Waiting for the installation to be complete is worth the investment, as the system will provide you with thousands of dollars in electrical bill savings over 25 years.
Solar panel installation process timeline
Installation is just one piece of the puzzle when it comes to switching to solar. Eight key steps make the entire process last anywhere from two to six months on average.
Choosing a solar installer
Time: 1 day to 2 weeks
Choosing a solar installer is the first and most important step of your entire solar journey. What company you pick determines not only the price of your installation but the quality and timeline as well!
You want to make sure you’re picking a reliable company that’s been in business for at least 5 years, have a NABCEP certified installer, and has positive customer reviews. This step can take you just a few hours, but it’s important to take the time to not only find a few installers you like, but also get and compare quotes from them. You definitely don’t want to cut corners when it comes to choosing the right company.
Getting at least three quotes will increase your chances of getting the highest quality installation at the best price point. The easiest way to find trustworthy solar companies in your area is by using our state-of-the-art solar calculator, which lets you see your potential solar savings and can help you start collecting quotes.
Find trusted solar installers in your area
Time: 1 week
After you choose your solar installer, they’ll need to perform a site assessment to make sure your roof is suitable for a solar installation. Someone from the installation company will come out to your house and take a look around to check out the condition, shading, size, and direction of your roof. They’ll also make sure your roof can handle the weight of solar panels, and take a look at your electrical panel to see if it would need any upgrades.
The site assessment will take less than a day, just a few hours at most, but we give this a timeframe of about one week to take scheduling into account.
Time: 2 to 3 weeks
Once it’s determined that your roof is ready for solar, an engineer will get started on designing your solar system. Your electricity usage, roof characteristics, local building code requirements, and utility requirements are all taken into account when designing the system.
The design process can take anywhere from two to three weeks on average, but it may take longer if your roof is more complex. Still, the planning stage for complicated systems probably won’t take much more than four weeks to complete.
Applying for building and solar permits
Time: 2 to 7 weeks
Adding solar panels is a construction project, so you need to have all of the proper permits before installation begins. Sadly, the permitting process is probably going to be the longest part of going solar. The exact permits needed vary from town to town. Some have very solar-specific permits while others have various building and electrical permits that need to be obtained.
Depending on the types of permits needed and the permitting processes in place in your municipality, it could take just two weeks to get approval – or almost two months. Let’s face it, having to wait that long for permits is annoying. But, the good news is your solar installer is the one who handles all the paperwork – you don’t have to worry about it.
Ordering equipment and scheduling installation
Time: 1 to 4 weeks
When your permits are approved, your company can start making moves to actually install your system. Some installers have the equipment on hand so they can get started on your project ASAP. You won’t have to wait for equipment to ship, but you might have to wait for them to have time in their schedule for your installation. That’s why we give this stage about a week minimum.
If your installer doesn’t have supplies at the ready, it could take a few weeks for everything they need to get delivered, especially with the ongoing solar industry supply chain issues.
Attention battery buyers: You may have to wait even longer if you are pairing your solar panels with solar battery storage. Batteries are in high demand, and it can be tricky to get your hands on one in a timely manner. Some installers may have them in stock, but don’t be surprised if the battery adds a significant amount to your wait time.
Time: 6 hours to 3 days
As we said earlier, the actual installation of your solar panels is going to be the shortest part of the process. For most residential solar installations, it’ll take just about 6 hours to complete!
Just like with the design of the system, the more complex it is, the more time it will take to complete. In general, your solar installation won’t take more than 3 days unless unforeseen issues arise during the installation. But, those worst-case scenarios are few and far between.
Time: 1 to 2 weeks
Your installation may be complete, but that doesn’t mean you can generate electricity just yet. You need a few more stamps of approval before you’re really up and running.
First, a local inspector will likely come out to make sure the system was installed properly and meets all of the correct building requirements. This serves as a safety measure, so any issues can be identified before the system is turned on.
Like the site assessment, this inspection will only take a few hours maximum, but it might take a week or so to schedule the appointment.
Utility interconnection and permission to operate
Time: 2 to 6 weeks
You’re also going to need to wait for permission to operate from your utility company before you can start using your solar panels. It should come as no surprise that waiting for utility approval can take a while.
Usually, the utility will come to your property, install a new electrical meter that can properly message your solar energy production, and do a quick inspection. Once this is complete, your interconnection agreement will get the final stamp of approval and you’re officially ready to power your home with solar!
So, how long does it really take to go solar?
When you consider everything you have to do in order to get solar on your roof, you can typically expect it to take as little as two months to as long as six months. Keep in mind that this timeline is an estimate, and it can vary greatly depending on your specific circumstances. Your solar installer will give you the rundown on what the timeline usually is in your area.
Installing solar is worth the wait
We get it, six months is a while. But, as the saying goes, good things come to those who wait. Even though it takes a few months to get the installation completed, in many cases it will take only 9 years (or even less!) for the solar panels to pay for themselves. Then, you’ll get over 15 years of completely free electricity. Plus, it’s good for the planet. who doesn’t love that?
If you’re still on the fence about whether or not you want to invest your time and money into a solar installation, you can use our free solar panel calculator to get insight on the number of solar panels you need, what incentives are available, how much you can save, and how long the payback period will be.
How to install solar panels in 7 steps
Let’s say, you’ve already purchased all the necessary supplies for a PV system. Now you might be wondering, what’s next? The solar panel installation process has many hidden details which are easy to miss, especially if you do it for the first time. In this article, we’ll introduce you to all the parts of a solar system and guide you through the task of making them work together.
DIY installation: Disclaimer
Homeowners normally don’t install panels themselves. In most states you need a permit from authorities to put PV modules on your roof. In some of them the installation can be performed only by certified contractors. If you are not a qualified technician, we highly recommend you to call professionals in order to be sure of the total safeness and effectiveness of your installation process. You can use this guide to be aware of the whole process and to make sure that the installers you’ve hired do the job right.
DIY installation of solar panels is more appropriate for smaller projects, such as powering your RV or boat. It’s a great way to reduce the costs if you are sure of your skills. Don’t forget, however, that some incentives and rebates are only available for the PV systems that have been mounted by certified contractors. DIY installation can also void the warranties for your solar panels.
Installation is about 10% of your system cost
How long does it take to install a solar panel? When it’s done by contractors, the process generally lasts two-three weeks. It starts with scheduling the inspections for your roof and getting permits. Putting panels in place is the final stage and only takes several days. Experienced installers usually don’t interfere with your daily house life too much, but you should be prepared for occasional power shutdowns.
The price for an installation depends on a set of factors:
- system size
- type of equipment you want to have
- geographical location
- incentives and benefits available in your area
- professional installers or DIY.
Now let’s look closely at the installation process that we broke down to 7 steps.
Step 1: Find the sunniest spot for your solar panels
Your main goal is to provide maximum solar exposure for your panels throughout the day. If you install solar panels on the roof, choose the southern side or the one which faces south-east or south-west. Ground installations are more flexible in this respect, but are rarely an option for residential systems – not everybody has a backyard big enough to accomodate 20 solar panels or so.
Make sure the spot you have chosen does not get shaded. Check the location in the morning, afternoon and evening – is it more or less equally exposed to sunlight throughout the day? Solar panels in shade may produce 75% less power than their rated output, so it is an important thing to think about in advance.
Solar Panel Installation – Understanding the Process
So, you’ve decided to pull the trigger on solar panel installation. What does the process of adopting photovoltaic power involve?
This is a common question – and a good one, we think. With any home improvement project, you need to know what you’re in for before you begin. And, making the switch to solar energy is no exception to the rule.
For an understanding of what to expect, check out the following step-by-step guide to the solar panel installation process.
Step 1: Consulting with Local Photovoltaic Contractors
First, contact a few reputable and highly-experienced local PV contractors and ask them to come out to your home or business for a professional estimate. Ask for the total gross cost for solar installation, and compare the price per watt (PPW) as you weigh the bids.
Step 2: Signing the Solar Installation Contract
Once you identify the PV contractor you want to work with, it’s time to sign the contract. But before you do, make sure it specifies the component brands and models to be installed as well as information on system performance, warranty terms and financing costs.
Step 3: Completing the Logistical Paperwork
After signing on the dotted line, the next step to solar installation is obtaining the building and electrical permits. Then, there’s filling out the forms for the available financial incentives. Fortunately, most PV contractors will handle these tasks for you.
Step 4: Ordering the Photovoltaic System Equipment
Once everything is a go, your PV contractor will order the solar panels, inverters and other photovoltaic power components your project requires. At this point, you’ll schedule a day to begin the system installation.
Step 5: Installing the Solar Panel System
On installation day, you’ll need to sign some paperwork. Other than that, you won’t have to lift a finger – but you can expect a bit of noise. Depending upon the size and complexity of your photovoltaic power system, the work may take a single day or several days to complete.
Step 6: Turning on the Solar Panel System
The last step to solar installation is to connect the system to the local power grid. This requires signoff from the city’s building inspector and, in many cases from the utility company. Your PV contractor will schedule the necessary inspections and make sure you get the green light to begin generating your own electricity.
Ready to Start the Solar Panel Installation Process?
If you’re all set to adopt photovoltaic power and your home or business is in the Intermountain West region, consult with a long-time leading local professional PV contractor.- Intermountain Wind Solar.
We can explain your options for grid-tied, off-grid and hybrid photovoltaic power, and our expert team can design an efficient, cost-effective solar panel system that provides you with a reliable source of electricity for decades to come.
Intermountain Wind Solar offers free consultations and estimates to homeowners and businesses in Utah, Idaho, Nevada, Oregon and Wyoming. To discuss your solar panel installation with our friendly and knowledgeable PV contractors, contact us today.
Solar Panels by Sunrun
Learn about our best-in-class solar products and services.
Experience Peace of Mind for Decades to Come with Sunrun Rooftop Solar Panels
When you team up with a solar company like Sunrun, you can create your own affordable, clean energy and gain independence from your utility company. A Sunrun solar installation can help power your home when the sun is out while you boost control over your energy usage and reduce your dependence on fossil fuels.
We offer several residential solar plans to help you start your solar journey. Find out which is the ideal fit for your budget and unique energy needs.
We offer some of the best solar rooftop panel systems on the market, and you can bring them home through a lease payment plan, flexible solar financing, or by paying outright. Our made-to-fit solar solutions, paired with exceptional service and our industry-leading solar guarantee, have positioned us as the leading residential solar and energy storage company in the U.S. 1
Solar panels are just one part of the solution to experience energy freedom and security. To ensure you get the most out of your home energy system, consider adding a solar battery back-up service like Sunrun’s Brightbox. Hundreds of millions of people were affected by blackouts from 2008 to 2017. 2 With Brightbox, you can keep your lights on and your food fresh during outages with a Smart, affordable, and reliable back-up power system.
Benefits of Adding Sunrun’s Battery Storage Service to Your Solar Panels
Brightbox doesn’t need dangerous, expensive, and toxic fossil fuels to work. 3 When the sun is out, it can store clean and affordable back-up power for later use.
Brightbox paired with a Tesla Powerwall can help you back up your entire home, or you can back up just the rooms you need with an LG Chem solar battery.
Tesla Powerwall and LG Chem solar batteries can last anywhere from 10 to 15 years, and they typically come with a 10-year manufacturer warranty for your peace of mind.
Solar with incentives
Our Automated Site Modeling tool is a revolutionary technology that allows us to design a custom Sunrun home solar energy system based on your roof’s unique dimensions and layout.
Sunrun’s Automated Site Modeling tool will use your roof’s individual profile, including shading, pitch, sun exposure, seasonality, and roof obstacles. This will ensure that the designed Sunrun solar panel system matches your home’s structure and unique energy needs. A customized system can let you know your potential control over your future electricity bills
Sunrun’s Product Selector is an innovative and simple tool. It lets you know in minutes which solar plan, with or without a home battery, can give you and your family more benefits in the long run, depending on where you live.
Sunrun’s Product Selector will use information about your roof’s type and pitch, your household size, and other important aspects, like if you have a home office or if you need back-up power, to recommend the best Sunrun home solar plan for you. This can help secure the peace of mind you deserve during rising energy costs and power outages while reducing your carbon footprint.
Does my state offer incentives to go solar?
See the states where Sunrun is currently available and the solar incentives that might be offered where you live. Some of the most common solar incentives include tax credits, property tax exemptions, and rebates. No matter what state you live in, you may be eligible for the Federal Solar Tax Credit (ITC) if you decide to purchase a home solar energy system.
You can get a Sunrun monthly plan to lease your solar panels or prepay for your renewable energy through a solar power purchase agreement or PPA plan. As a result, any incentive savings you would receive through tax credits and rebates with a system purchase can be passed to you in the form of a lower solar bill.
How do solar panels work?
You can’t talk about solar panels without talking about silicon. Silicon is a non-metallic element and the second-most abundant material on earth. 4 It can also convert sunlight into electricity, and it’s a key component in a solar system (also known as a photovoltaic, or PV system). 5
Solar panels, solar cells, or PV cells, are made by slicing crystalline silicon (also known as wafers) that are millimeters thin. These wafers are sandwiched between protective glass, insulation, and a protective back sheet, which make a solar panel. The back sheet helps to regulate the temperature and humidity to optimize the solar panel’s efficiency. 6 Multiple solar panels connected together create a solar array, and ultimately, a solar system.
Then there’s the physics of how solar cells work: Electricity is made when electrons move between atoms. The top and bottom of a silicon wafer in the solar cell are treated with small amounts of atoms of extra materials—such as boron, gallium, or phosphorus—so that the top layer has more electrons and the bottom layer has less. When the sun activates the electrons in these oppositely charged layers, the electrons move through a circuit attached to the panels. This flow of electrons through the circuit is what generates the electrical current that ultimately powers a home. 7
What are the different types of solar panels?
Monocrystalline solar panels:
Monocrystalline solar panels have the highest efficiency and power capacity out of all other types of solar panels. Another reason why people choose them is because of how they look. The solar cells within monocrystalline panels are square-shaped and have a single, flat black color, making them the most popular type of solar panels among homeowners. 8 Sunrun uses monocrystalline PV modules in all its home solar systems.
Polycrystalline solar panels:
The manufacturing process of polycrystalline solar panels is less costly than monocrystalline panels, but it also makes them less efficient. Usually, polycrystalline solar panels don’t have the corners cut off of them, so you won’t see the large white spaces on the front of the panel that you see on monocrystalline panels. 8
Thin-film solar panels:
Thin-film solar panels are less costly and easier to install than their counterparts. Still, they aren’t the best option for a home solar installation due to their efficiency, lightweight material, and durability. 8
How long do solar panels really last?
When you consider investing in a solar installation, you might wonder how long home solar panels last. Studies show that solar panels can last anywhere from 20 to 30 years, or sometimes longer. 9 Still, this doesn’t mean the panels on your roof will stop producing electricity after a couple of decades. It just means their energy production will decrease by what solar panel manufacturers consider optimal to meet the average household’s energy needs.
Do home solar systems have a warranty?
All of our solar equipment is backed by factory warranties. On top of that, our monthly solar lease plan and prepaid solar plan (also known as a solar PPA) come with 24/7 proactive monitoring and free maintenance on us. If we notice that your rooftop panels or solar battery aren’t working at their full capacity, we’ll send an expert over to fix it without you lifting a finger. This benefit sets Sunrun apart from the other solar installers in the country.
How does Automated Site Modeling work?
After you enter a few details about your home, our Automated Site Modeling tool will analyze hundreds of thousands of variables in home solar system designs to build a high-resolution image of the ideal system for your roof. These factors include your home’s pitch, seasonality, sun exposure, shading, and roof obstacles. This helps Sunrun guarantee you receive maximum benefits from your new home solar system.
How does Sunrun’s Product Selector work?
After you answer a few simple questions about your home’s details, lifestyle, and electricity usage, Sunrun’s Product Selector will let you know if a monthly lease plan, prepaying for your solar energy, financing a system, or purchasing outright—along with a back-up power service—is the most cost-effective solution for your unique needs.
Are Automated Site Modeling and Sunrun’s Product Selector really free?
Yes. At Sunrun, we’re committed to providing you with the best technology, services, and tools, like our Automated Site Modeling tool and Product Selector, to make your switch to solar as affordable and straightforward as possible. This can help you worry less about controlling your electric bills and protecting your home during outages while reducing your carbon emissions for decades.
Do solar panels get hot?
Rooftop solar panels can get hot, particularly during scorching summer days. If the panels do get hot or overheat, they can produce less energy as the temperature rises above their optimal energy production range.
In general, residential solar panels are designed to reach their peak efficiency level at 77 °F (25 °C), but their efficiency will decrease by 0.5% for every degree above this temperature. The actual percentage of lower production varies by the solar panel’s manufacturer and model. Ultimately, you want to aim for an exterior temperature range of 59 to 95 °F (15 to 35 °C). Yet, it’s unrealistic for rooftop solar panels to stay within this range all year, especially in places where temperatures can go past 100 °F (37.8 °C). Fortunately, most solar panels can withstand heat up to 149 °F (65 °C). 10
Nonetheless, solar panel overheating can be prevented. Many solar panel manufacturers cover the panels in a material that generally conducts and vents heat away from the glass. In addition, solar panels are usually mounted a few inches above the roof, which allows airflow space to help move heat away from the panels.
Despite the reduction in efficiency from extreme heat, solar energy generation doesn’t stop. The lower electricity production due to scorching weather balances out with the longer days of sunlight throughout the seasons. Although solar panels work best on cold, sunny days, they produce solar power year-round in nearly every location and climate.
Do solar panels work in cold weather?
Solar panels create energy from sunlight—not the sun’s heat. In fact, solar panels produce electricity more efficiently in cooler conditions. Even in the most frigid weather, solar panels can turn sunlight into electricity.
How does this work? Colder temperatures enhance solar energy production efficiency, which increases the amount of electricity produced. Electrons are at rest in cooler climates. When the electrons in solar panels are activated by increasing sunlight, a voltage difference is attained that creates an electric current.
Warmer summer temperatures raise the overall energy levels of electrons in solar panels. This increased energy level decreases the energy differential that can be gained, producing less energy. A higher energy state interferes with solar panel electricity production since some energy transfers into heat instead of electricity. Your home doesn’t need to be in a warm-weather state like Arizona, California, Nevada, or Texas to generate year-round reliable solar power.
Do solar panels work at night?
While solar panels need sunlight to create electricity, there are two ways you can benefit from solar power during the nighttime: enroll in a net energy metering (NEM) program (if it’s offered where you live), or add a home battery storage service, like Sunrun’s Brightbox.
Net energy metering (NEM): Lower-cost grid energy at night
If NEM is offered in your state and by your utility, you may be eligible to earn credits on your bill for the excess solar energy you produce and send to your utility company. 11 At night, you could use those credits toward drawing electricity from the grid at a lower cost. Net metering may help you save money on your future electricity bills. Visit your utility company’s website for more information.
Solar battery storage: Reliable, affordable back-up energy, day and night
A battery storage service like Brightbox can let you store the excess solar power you produce for later use. This stored solar energy can help keep your devices and appliances running at night, during outages, cloudy days, and rainy afternoons.
Brightbox offers two lithium-ion solar battery storage options: Tesla Powerwall and LG Chem. Tesla Powerwall can help yo back up your entire home while LG Chem can help you back up to four circuits inside your home. There are also differences in software and app functionality.
Request a free, personalized quote to connect with a Sunrun Solar Advisor and determine which Sunrun back-up solution would work best for your home.
How does Brightbox work?
Brightbox allows you to store the excess energy your solar energy system produces during the day to use it in the evening, at night, or when the electric grid fails due to physical damage or an extreme weather event or.
Do I need solar panels to use Brightbox?
Aside from very rare exceptions, Sunrun’s Brightbox service includes rooftop solar panels. Brightbox can store 100% clean, renewable, home-grown solar power directly from the rooftop panels when the sun is out, so you can use it when you need it most.
Can I add Brightbox to my current home solar system?
At this time, Brightbox with a Tesla Powerwall or LG Chem solar battery is only available in the installation of a new Sunrun home solar system due to tech compatibility issues. We can’t install rooftop solar panels or a home battery if you already have an existing solar installation or if Brigtbox’s battery storage service isn’t available in your area.
What happens during a solar installation?
Once you’re approved for a solar installation, your property will undergo a site assessment, and an expert solar technician will schedule a visit with you to confirm your system design.
After that, our Solar Design Experts will make any necessary adjustments to your design and get your final approval. Once it’s approved, we’ll submit your design to the city for permitting, which can take up to eight weeks. From there, either Sunrun or one of our local certified partners will start your solar installation. We only partner with the top-rated solar installers, so you can rest easy knowing you’ll have the highest quality solar installation available.
When your installation is finished, the city or county will perform a final inspection of your system. Once it’s approved, it’ll be connected to the grid, and we’ll submit your documents to the utility company. After your utility company grants Permission to Operate (PTO), you’ll be all set to start powering your home with the sun.
What happens if I move?
We have an entire team of professionals standing by to help you sell your solar home and transfer your contract, if applicable, to the new owners. Sunrun makes it easy to pass your solar lease or power purchase agreement (PPA) to the new owners. Our Service Transfer Specialists handle everything from educating realtors and potential buyers to working with escrow officers, title agents, home inspectors, as well as anyone else who might need to know about your system and solar lease or PPA agreement.