Rooftop solar panels: what they are, how they work, and frequently asked questions
We are in the midst of a revolution in the way people think about and use electricity. Rooftop solar panels have upended how electrical power is generated, delivered, stored, and used.
Home and business owners who were previously only consumers of electricity can now become producers too. Their rooftop solar systems often generate more electricity than they need during the day, then they draw power from batteries or the grid in the evenings, earning credit from their utility companies for any difference.
If you haven’t yet joined the renewable energy revolution, here’s some information about your options, how solar panels work, and how they can save you money.
See how much you can save on your electricity bill with solar panels
- Rooftop solar panels make electrical energy from the sun while mounted on already-existing buildings and vehicles.
- The vast majority of rooftop panels are made using a silicon-based semiconductor material sandwiched between layers of glass and watertight plastic, surrounded by a metal frame.
- Solar panels are connected to a home or business using inverters that change direct current solar power into alternating current that can be used by appliances and devices.
- When connected to the grid, a rooftop solar panel system saves its owners money on electric bills by reducing grid usage and earning credit for energy sent to the grid.
For homes and businesses
Rooftop solar panels in the lab yard at SEI
There are many different types of solar panels, but crystalline silicon solar panels are the ones that work best on the rooftops of homes and businesses. These panels are rigid, made to withstand the elements, and easy to install on metal racks attached to a roof.
Another choice that is growing in popularity is building-integrated solar products like solar shingles, which are built to look more like traditional roofing materials.
Crystalline silicon solar panels
A Silfab Prime solar panel. Image source: Silfab
Most people think of crystalline silicon solar panels when they think of rooftop solar. They’re by far the most popular kind of solar panel, used in over 90% of solar installations worldwide.
These solar panels are made using strings of solar cells, wired together in series and sandwiched between glass and a special watertight plastic layer called the “encapsulant”.
Silicon solar panels can be made with many different configurations of cells, but the most popular ones come with either 60 or 72 cells. Newer modules use half-cut solar cells, so they usually have 120 or 144 half-cut cells. Some of the latest solar panels use larger cells in a 54-cell or 108-half-cell configuration.
Crystalline silicon panels come in many different sizes, but they’re typically about 3.5 feet wide, 6 feet tall, and weigh between 40 and 50 pounds. The average modern home solar panel can output 400 watts under full sun.
Building integrated means the solar panels are the roof. Image source: Tesla
Believe it or not, some people don’t like the look of solar panels mounted on racks on their roofs (weird, right?). Building-integrated solar photovoltaic (BIPV) products like solar shingles are built to cater to them.
In most cases, BIPV products use silicon solar cells, but instead of being wired into a large solar panel, they are embedded into something that looks similar to a roofing material.
The most famous example of BIPV is the Tesla Solar Roof, which uses solar cells in strips of high-tech shingles to emulate a premium roof’s look while generating electricity. The Tesla shingles are installed as part of a whole roof system, in which shingles on the sunniest parts of the roof have solar cells inside them, and less-expensive “dummy” shingles cover the shady areas.
Roofing products companies like CertainTeed and GAF also offer BIPV products that integrate with their traditional roofing shingles.
Bifacial solar panels
Bifacial solar panels in a home awning. Image source: Prism Solar
For flat business roofs where the roof’s surface may reflect some sunlight up at the back of the panels, it may be good to choose bifacial solar panels. These special types of crystalline solar panels have glass on the front and back, allowing the underside of the solar cells to receive reflected light. If you can see through the panel between the cells, you’re looking at a bifacial solar panel.
Solar panel manufacturers claim that bifacial panels can generate up to 30% more power in the same space.
If you do a lot of boondocking (camping in an RV without hookups to electricity, water, and sewer), having solar panels mounted on your RV roof is basically a necessity. Most RV owners only need a little bit of power, and a couple of small solar panels and a portable solar battery can be enough to provide electricity all day and night.
If you’re looking for solar panels for an RV, you’ll probably still be looking for crystalline silicon solar panels, but they’ll likely need to be smaller to fit on the RV roof. You could also choose a flexible solar panel made with thin-film solar technology like amorphous silicon or cadmium telluride (CdTe).
Silicon solar panels for RVs
A 36-cell solar panel made by Hightec. Image source: Rocky Mountain Off-Grid
Rigid solar panels designed for RV roofs are typically smaller and output less wattage than the ones used on homes and businesses. A typical solar panel for RVs contains 36 solar cells laid out in a 9-by-4 pattern. These panels are designed to be paired with 12-volt deep cycle batteries that are popular among RV enthusiasts.
Top brands for this type of solar panel include Renogy, BougeRV, and Grape Solar.
Flexible and thin-film solar panels
If you’re looking for something a little more flexible—literally and figuratively, you might choose a thin-film or portable solar panel for your RV. Renogy makes light and flexible solar panels using monocrystalline silicon, while BougeRV now offers a CIGS thin-film solar panel for RVs.
A marketing image of the BougeRV CIGS thin-film solar panel. Image source: BougeRV
The advantage of these panels is that they’re easy to install with just adhesive, and they keep a low profile on the rooftop. A CIGS thin-film panel also performs much better under partial shade or very hot conditions. In a desert environment, a crystalline silicon solar panel can lose 10 to 20% of its ability to output power, while a CIGS thin-film solar panel will continue operating near its maximum output potential.
A disadvantage of thin-film solar panels is the cost. Current for thin-film products like the one above are around 2.5 times higher than for traditional silicon solar panels.
How solar panels work
Rooftop solar panels work using the photovoltaic effect. The word “photovoltaic” means “electricity from light” and is often shortened to “PV.”
Solar cells use a semiconductor material (silicon, in most solar panels) that is coated with other substances. When photons of light hit the cell, they excite electrons to higher states, which are then directed along a wire to deliver power to the circuit. Once the power is delivered, the electrons return to their low-energy state until they are excited again.
Solar panels are rated by how many watts (W) they can produce under full sun; solar system size is measured in kilowatts (kW) of output, and energy production over time is measured in kilowatt-hours (kWh). See more on kW vs. kWh here.
How solar panels connect to your home or business
PV solar panels produce direct current (DC) power when the sun shines on them. But nearly all homes and businesses use alternating current (AC). The DC solar power must first be converted to AC power before we can use it. This is accomplished using solar inverters.
There are two main kinds of inverters used in solar installations today: the string inverter and the micro-inverter.
- String inverters convert the DC output of a whole solar array into AC power
- Microinverters attach to each solar panel individually, and the AC wires are then connected inside a combiner box
A microinverter attaches to the back of each solar panel, while string inverters accept input from many panels.
In a typical home or business, the AC output of a solar panel system connects to the electrical panel, which allows the AC power to be distributed to the home’s circuits or sent to the grid. This is called a grid-tied solar system.
If the home isn’t connected to the grid, the solar system needs to be connected to a battery storage system to store energy and make it available to the house when the sun isn’t shining brightly enough to power everything.
How rooftop solar panels can help you save money
If you have a grid-tied solar system, the energy produced by your solar panels offsets energy you would have purchased from the utility. So any solar energy your panels produce that gets used in your home directly reduces your energy bills. But what about when solar panels produce more power than you need?
Every utility company has different rules for excess solar energy. Some take whatever you send and don’t pay you anything in return, while others pay just a few cents per kilowatt-hour. The best utilities offer a billing arrangement called net metering, under which every kWh of excess solar energy gets recorded as a credit on your account.
When your home draws power from the grid at night or when the sun isn’t shining, that usage is offset by any credit you’ve stored up. Under true net metering, excess credits left over at the end of the month roll over forever until you use them.
Many states guarantee net metering to some or all of their residents. Research your own state net metering policies to learn what they are before going solar.
Frequently asked questions
Here are the most commonly-asked questions about solar panels. Click on the links to see the answers below.
Who can use rooftop solar panels?
Anyone with a rooftop can use solar panels, but the most suitable roofs meet the following criteria:
- Flat or tilted facing the south, east, or west
- Constructed using asphalt shingles, clay tiles, metal, membrane, or slate
- Not in need of replacement in at least the next 10 years
- Unshaded for most of the day
How long do solar panels last?
Solar panels are designed to last for several decades. Most solar panels on the market come with warranties of 12 to 25 years that cover materials and workmanship and 25 to 30 years of guaranteed power production ability.
Only 5 out of 10,000 solar panels will experience a failure of materials and workmanship in its lifetime, and those that don’t fail should make it to 30 years easily.
How efficient are solar panels?
Efficiency measures how much solar energy a PV panel can convert into electricity. The very best silicon solar panels convert around 23% of photons into charge-carrying electrons. That may seem like a low amount, but it’s not. The theoretical maximum efficiency of a silicon solar cell is around 33%, so modern solar cells are already most of the way there.
Work is always being carried out to increase efficiency, but modern solar panels already generate enough energy to pay their cost back quickly. There is no technology promising huge gains in efficiency in the near term, but there will someday be improvements.
Any single semiconductor material can only convert a specific range of wavelengths of light into electrical energy. The best chance to increase solar cell efficiency is to add layers of material in tandem with silicon solar cells to capture a greater range of wavelengths. Perovskites are currently the most promising technology to do this, but they won’t be ready for widespread use for years to come.
Is rooftop solar better than a huge solar farm?
The United States needs more rooftop solar and more solar farms if we’re going to avoid the worst effects of climate change. But new solar farms take up a lot of land and often require expensive upgrades to electricity grid infrastructure that takes power to places where it is used, so they need to be strategically sited.
Rooftop solar produces power where it will be used, and takes advantage of structures that are already built. Grid upgrades are sometimes necessary, but in general, rooftop installations require only proper design and installation without taking additional land. Whenever possible and economical, rooftop solar is best.
Will rooftop solar panels work in a power outage?
Most people don’t know that a standard grid-tied PV system is designed to shut down in the event of a power outage. Without shutting down, a solar installation could send energy to the grid while utility line workers are repairing the wires, potentially endangering them.
If you want to use solar panels in a power outage, your system needs the capability to go into “islanding” mode. This cuts your home off from the rest of the grid and prevents the backfeed of energy along utility wires. In most cases, an islanding system needs a battery bank to store excess solar energy, but there are some solutions where a home can operate at a reduced capacity with only solar energy, such as the Sunlight Backup features possible using Enphase IQ8 microinverters.
How much do rooftop solar panels cost?
The cost of rooftop solar panels varies widely depending on the state where you live, how many solar panels you need, and whether you install yourself or choose a professional solar installer. Yes, DIY solar is possible, but it’s not for the faint of heart.
A modest single-family home in the United States usually needs about 6 kilowatts of solar panels, and the average cost of solar panels from an installer is around 17,700 before incentives. The easiest way to compare solar panel is by cost per watt, so the average cost per watt for a 6 kW system is 2.95 before incentives.
Are there incentives for rooftop solar panels?
Yes. The U.S. federal government offers the clean energy tax credit that covers up to 30% of the upfront costs homeowners pay to install solar panels. It also offers adders to that credit for commercial solar installations that use locally-produced equipment or take place in low-income areas and serve customers there. The federal tax credit now also covers batteries, even if they are not installed alongside solar panels.
In addition to the federal government, many states, municipalities, and individual utility companies offer tax credits, rebates, and even battery incentives that can further reduce the cost. You can learn about the solar incentives offered in your state here.
Is rooftop solar worth the cost?
In most places in the United States, the answer is yes! The cost of a solar system from a full-service solar installer can be paid back by electric bill savings within 5 to 10 years, considering the incentives currently available and expected increases in the cost of electricity.
That said, every home or building is different, and those differences can result in changes to the final cost of installing solar. If your roof needs replacement, or if it’s too shady, or if you need a main electrical panel upgrade during the solar installation, that can change the price dramatically and affect the likelihood that the system will pay back its cost in a reasonable amount of time.
To learn whether solar panels are right for you, it’s best to get an estimate of installation costs from several different solar companies and speak to a trusted financial advisor and/or tax expert before making a decision.
A roof with power added.
The new Timberline Solar™ roofing system is so advanced it makes solar simple.
Homeowners no longer have to compromise when adding solar power to their roof. Get a great-looking roof, a single GAF-backed warranty, and solar energy.
Water-shedding and warranted
Timberline Solar™ is made up of shingles, not panels or heavy tiles. These shingles are water-shedding, strong and warranted to withstand winds up to 130 mph. Rack-mounted solar installations—where the solar is separate from the roof—require the drilling of dozens of holes into the roof membrane. Any resulting damage related to those holes is not typically covered by roof warranties.
For homeowners who already know the quality of GAF roofing products, the Timberline Solar™ roof has the same wind and water-shedding warranty coverage as Timberline HDZ.
Investing in a home is no small matter – and the way it looks is important. Timberline Solar™ has a design that blends in with the aesthetic of the house, with elements that add visual appeal like an architectural shingle.
Here at GAF Energy, we strive to not just meet homeowners expectations for roofing reliability, but to achieve breakthroughs with aesthetics.
How solar savings work
With a GAF Energy solar roof, you’ll not only get a roof that’s durable and has curb appeal, it’s also financially Smart, since you can save on your energy bills over time.
“With Resnick Roofing and GAF Energy, we had a clear sense that we would be working with good teams. It made the jump to solar easy when we needed a new roof.”
Meeting–and raising–the bar
Timberline Solar™ can supply your home with electricity every day, every hour the sun is shining.
And while we don’t want to talk tech jargon, it’s met some industry-leading standards such as UL 7103 certification, which means it’s been through rigorous testing from an independant certification company that’s been around for over one hundred years. We’re committed to the quality of our product.
“I love that my customers can get a new roof AND solar at the same time, from one source… R E Roofing. As a roofer, I’m committed to giving my customers a roof that looks good and protects them from the elements. And by getting the roof and solar from us, I’m not dealing with follow-up calls from one of my customers about punctures in the shingles from a rack-mounted solar system. This is one sleek, integrated design that all works together.”
It makes sense (and cents)
A solar roof is one project, one design, one crew, one straightforward proposition. And, it may pay for itself over time, as it generates energy for the home and reduces monthly electric bills.
“The overall cost of my roof with the solar was surprisingly affordable and the financing they offered was very competitive. Having the same installer for both the shingles and solar simplified the installation process and eliminated the need for contacting multiple parties if any issues arise.”
“Installation? A breeze.”
That’s a direct quote from one of our roofing partners. Timberline Solar™ Energy Shingles are the world’s first nailable solar shingles, which makes Timberline Solar™ easy to install. This solar roof goes on with a nail gun, and roofing know-how.
That means local GAF-certified roofers who live and work in your community can install the product.
Frequently asked questions about Timberline Solar™
Why are GAF Energy solar roofs my best option for solar? Timberline Solar™, integrated solar roofing from GAF Energy, is the first true solar roof. It incorporates solar technology into traditional roofing materials and processes, and uses the world’s first nailable solar shingle, which lays flush against the roof deck, providing durability and protection that look great. With constant utility rate inflation, Timberline Solar™ was designed to be an affordable solar roofing option. If you’re using solar to power your home in lieu of electricity from the grid, your energy may be lower. This all means that your Timberline Solar™ roof could save you money, allowing those savings to offset the cost of your new roof over time. And with solar roofing becoming more popular, it could even benefit your home resale value. How much does a solar roof cost? Pricing of Timberline Solar™ for the average home varies based on a number of factors, including the size and slope of the roof, the shading around the home, and how much sunlight reaches the roof throughout a typical day. A Timberline Solar™ roof is designed to be affordable and is typically comparable to a new roof plus traditional rack-mounted solar. Timberline Solar™ is currently available for residential installation, and may be available for commercial buildings in the future. What are the benefits of solar shingles compared to rack mount solar panels? Timberline Solar™ is the first true solar roof on the market. It incorporates the world’s first nailable solar shingle, which roofers can install as easily as regular roofing shingles, with only a nail gun. The benefit of this roof-integrated solar system is its seamless, waterproof installation that mimics traditional shingle installation. With most residential solar systems on the market using rack mounted panels or tiles, these setups require specialized installation skills and structures that can require ballast and/or can puncture your existing roof with lag bolts. This could disrupt the waterproofing to your roof, possibly degrading your roof quicker. Plus, the smaller form factor of the Timberline Solar™ Energy Shingle (ES) as compared to a solar panel allows for installation on more complex roof shapes such as dormers or hipped roofs. Are solar shingles as efficient as panels? Due to the unique design of Timberline Solar™ as a complete roofing system, efficiency cannot be calculated in the same way as a traditional solar panel. The ES is made out of the same high-efficiency mono PERC cell technology found in Tier 1 solar panels, and depending on a home’s specific roof geometry, Timberline Solar™ may fit more kW per roof than traditional solar panels. Does my solar roof come with batteries or grid connection? Timberline Solar™ is designed to be operated in connection with the electric grid, and is compatible with many energy storage offerings on the market. AC-coupled batteries are designed to be added to existing solar installations at any time. Other energy storage systems may require unique equipment for existing solar installations. All options and features for energy storage are site dependent and unique to the particular energy storage system. Please verify with a licensed energy storage contractor in advance that the specifications are right for the installed solar components and the desired operation modes (backup, self-consumption, time-of-use load shifting, etc.). What tax credits are compatible with GAF Energy Solar Roofs? We encourage roofers and homeowners to consult their tax advisors on all available solar tax incentives. Where is Timberline Solar™ available? GAF Energy’s strategic rollout process is well underway, with the immediate goal to bring Timberline Solar™ to every state in the U.S. Our vision is energy from every roof. Our major markets right now FOCUS on the Southeast, Midwest, Northeast, Mountain West, and West Coast of the US. We operate in states like California, Colorado, Texas, Florida, South Carolina, North Carolina, Virginia, Maryland, New Jersey, Pennsylvania, and New York–and add new service areas regularly. Please contact us at www.gaf.energy/timberline-solar to find out if we are available in your area—we may very well be! If you are not in an active territory yet, we can alert you when we open service in your region. What is maintenance like on my solar roof? Timberline Solar™ is warrantied for diverse weather conditions such as snow, rain, and wind, and the system is designed to require little to no maintenance. Seasonal rains should help keep the solar shingles clean of dirt and debris, but if not, homeowners can either gently rinse their shingles (only when they’re cool). Timberline Solar™ provides excellent, durable protection from the elements while generating reliable clean energy for the home. It’s a roof, with power added, designed to protect your home from leaks and other weather-related issues. Timberline Solar™ customers can monitor output and track their clean energy production by logging in to the GAF Energy customer portal. Solar roof monitoring puts data directly in customers’ hands and makes it easier to readily detect any issues.
GAF Energy 5981 Optical Court San Jose, CA 95138
How to Install Solar Panels on a Home Roof and Connect Them
Solar energy is quickly establishing itself as the quintessential modern way to generate power. It’s green, renewable, and can reduce (or even eliminate) your monthly electric bills.
There are numerous advantages and benefits to installing your own set of solar panels on your roof rather than paying for professional installation.
But how do you go about doing it?
Well, you’re in the right place.
In this guide, we’re going to take you through all the benefits of installing solar panels on your roof and how you can DIY it all by yourself!
Why You Should Install Solar Panels on the Roof
There are numerous pros to installing your own solar panels. To make them easier to digest, we’ve broken down the key points below for you to review.
Solar Panels Are a Renewable Source of Green Energy
Over the past two decades, the damage caused by climate change has become clearer and clearer. Life on our planet is in danger, and we all feel the pressure to change our habits and live greener.
Generating your own clean, renewable energy from the sun is an excellent way to do this, and that’s exactly what solar panels provide you with!
If you’re looking for a greener way to live, solar is a fantastic place to start.
Solar Panels Can Help You Save Money
Living greener isn’t just about saving the planet. You can also keep more green in your wallet.
Generating your own energy means less (or zero) reliance on the grid. You can reduce your electricity bills or eliminate them altogether. The initial investment can be significant, but over time you will certainly start to see the financial benefits.
With the world’s fossil fuel supply diminishing and an unpredictable geopolitical situation — not to mention the natural disasters exacerbated by climate change — the price of on-grid electricity is likely to keep climbing.
At the same time, an aging energy infrastructure has made the grid less reliable than ever.
With the rapidly declining and improving technology of solar power, there’s never been a better time to take the plunge.
Solar Panels Are Easy to Install
Installing your own solar panels on your roof might seem like a massive undertaking, but it really isn’t.
You may be entirely capable of doing it yourself!
We’ll walk you through a DIY solar installation step-by-step a little further down. Home renovations don’t have to be stressful or excessive, and solar panel installation is neither.
Solar Panels Are Low Maintenance
Not only are solar panels easy to install, but they also require next to no maintenance. Once the panels are set up on your roof, you can essentially just forget about them. Solar power systems require no refueling and — if purchased from a reliable manufacturer — are highly durable. The Rigid Solar Panel from EcoFlow features an IP68 weather resistance certification, making it totally waterproof! These panels are designed to last with minimal intervention. You may need to clean them once or twice a year, but the rain will generally take care of that.
What to Consider Before Installing Solar Panels on Your Roof
Now that you know why solar panels are such a good idea, we’re sure you’re eager to purchase your own.
Don’t rush to the stores (or your laptop) just yet — there are some key considerations to make first.
You don’t want to invest in technology that doesn’t meet your electricity generation needs or install the incorrect equipment.
Consider the following factors carefully before jumping into solar.
Location isn’t just about the amount of sunshine you receive on a daily basis. Peak sun hours have an impact, but solar panels can pick up energy even in low-light situations. You don’t need to live in a desert for your solar panel to generate adequate power.
However, if your roof is positioned under heavy shade, you won’t reap the same benefits as a solar panel that receives direct sunlight.
Do some research on how much sunlight your location receives on average and consider factors like shade. It pays to know how worthwhile your investment will end up being before committing.
How Much Energy Does Your Home Use?
Numerous factors affect how much energy your home consumes. The number of people in your house, how many devices you have running concurrently, and your home’s size all contribute. Make sure you review how much electricity your home consumes, with specific reference to the wattage of essential devices and appliances, before purchasing solar panels and a solar power system.
Doing the math will give you a clearer insight into how beneficial the switch to solar will be for you!
The Condition of Your Roof
Solar panels do not typically damage your roof, but they do exert additional weight on the existing structure. This is because they are usually mounted via panel hooks or similar devices.
If your roof hasn’t been inspected in a few years or has shown signs of degradation (rot, woodworm, rust, etc), it might not be the best time to invest in roof-mounted solar panels.
The last thing you want is to splash out on a set of solar panels only to find your roof can’t support them.
Besides, portable solar panels are also a more than viable option. You can set them up in your backyard — and take them anywhere.
The Brand You Purchase From
Last but perhaps most importantly, you need to consider which manufacturer to purchase your solar panels and the solar power system that converts and stores electricity from.
Not all brands (or solar panels) are created equal — and reputation matters!
You should always read up on the brand you’re investing in before proceeding through checkout. You might think you’ve found a bargain, but if you’re purchasing subpar technology, it will likely need to be replaced much sooner than you’d like.
How to Install and Connect Solar Panels on a Roof – Step by Step
Now let’s get into the nitty gritty: installation!
When it comes to installation, rigid solar panels are somewhat similar between brands. But there are some unique differences.
This step-by-step guide is a generalized approach, but it should still apply to your installation.
It isn’t as complicated as you may think, so let’s get into it already.
Attach the Solar Panel Mounts
Once you are safely up on your roof, the first thing you will need to do is secure your solar panel mounts. Mounts are what your panels will attach to and ‘hang’ from, so you must ensure they are completely stable.
Also, consider how you’re going to maximize sunlight exposure throughout the day. Attach your mounts to the side that receives the most daylight at an 18-36 degree angle.
Secure the Solar Panels in Place
Once your mounts are securely in place, it’s time to place the panels themselves.
EcoFlow offers both rigid and flexible solar panels to suit your rooftop installation needs. No matter how sloped or unusual your roof may be, you should have minimal difficulty fitting them in place.
Just make sure all of the nuts and bolts are tightly fastened, securing the panel to the mount. This will help ensure that they stay precisely where you put them, no matter the weather.
Wire the Solar Panels to the Inverter or Portable Power Station
Next is the wiring. This may be the part you find most daunting, but it’s actually a relatively simple process. In most cases, MC4 cable connectors are used because they are compatible with all kinds of solar panels. You should only attempt this when the household electrical supply is entirely shut down, or you run the risk of electrifying yourself rather than your panels.
Install the Solar Inverter or Use a Portable Power Station
The inverter converts the sunlight your panels absorb into electrical energy you can use and store. EcoFlow’s portable power stations and solar generators have the inverter built in, as well as everything else you need for a true plug-and-play solar power system.
Your inverter should usually be installed near your main electrical panel, ideally in a cool location.
If you choose to install the solar inverter outdoors, make sure it’s out of the direct sun.
Connect the Inverter to the Consumer Unit
Finally, you need to connect the inverter to the consumer unit (fuse board). You will also need to connect solar batteries to your consumer unit to store the electricity you generate.
This step is unnecessary with EcoFlow Portable Power Stations and Solar Generators, which are both all-in-one solar power system solutions.
A generation meter alongside can tell you how much energy your solar panels are generating.
With many of EcoFlow’s products, you can access this information and much more using the EcoFlow app on your smartphone.
Congrats, you’ve completed your very first installation!
NOTE: Your solar panels should always arrive with a specific installation manual for your system. Our guide is a catch-all for numerous solar panels, so make sure to refer to it as a high-level guide alongside your product manual.
Do I Need Permission to Install Solar Panels on My Roof?
In most cases, no, you do not need to apply for planning permission to install solar panels on your roof. Typically, it’s considered permitted development and shouldn’t affect neighbors in any meaningful way.
After all, you aren’t expanding your property. You’re just adding to what’s already there.
However, some exemptions to this may apply depending on your location and local regulations. Particularly if the following criteria are breached:
- The panels rise higher than 8 inches (200mm) from the roof
- Your home is a listed or landmark building
- You live close to a listed or landmark building
Check your local and national guidelines for specific information relating to your home, but for the most part, you should be good to go!
If you are denied planning permission for a rooftop solar installation for whatever reason, don’t worry, it isn’t the end of your solar journey. EcoFlow offers a range of portable solar panels that can be used with portable power stations (such as the DELTA Pro) to generate power no matter where you are — and you don’t have to ask anyone’s permission!
Installing solar panels on your roof can seem like a huge undertaking, but it can prove highly worthwhile.
Not only do you get energy independence, but you also do your part for the environment and save money on utility bills in the long run.
Consider purchasing your own solar panels today and see for yourself why so many people and businesses are turning to solar power.
EcoFlow is a portable power and renewable energy solutions company. Since its founding in 2017, EcoFlow has provided peace-of-mind power to customers in over 85 markets through its DELTA and RIVER product lines of portable power stations and eco-friendly accessories.
Is your home suitable for rooftop solar panels?
Rooftop solar panels are becoming more popular in the UK as people battle the cost of living crisis, but not every home is suitable. Our guide aims to help you determine if you can install solar panels on your roof.
Affiliate Disclaimer: All products and services featured are independently selected by our editors. However, when you buy something through our retail links, we may earn an affiliate commission.
Could solar panels for roofs be the solution to cutting energy bills? With the energy crisis and cost of living on the rise with no end in sight, many homeowners are looking for ways to cut costs. As of October 1, 2022, the current Energy Price Guarantee. set by the UK government, was capped at £2,500—27% more than last year —and this is due to rise to £3,000 per year from April 1, 2023.
Solar panels are a way of generating renewable energy, which in turn can reduce energy bills and help your home to be less reliant on the National Grid and fossil fuels. The most common place to install your solar panels is on top of your roof. In order for them to function at full capacity, you need them to be in an optimal position to receive the sun’s rays. So it makes sense that this is on top of your roof, free of obstruction and hopefully a place that receives lots of daylight.
The amount of energy that your solar panels can generate will depend on the angle of your roof, which direction it is facing, and the number of daylight hours. It can be tricky to figure out how this will affect your roof solar panels, and that’s why we’ve done the research for you.
Is my roof suitable for solar panels?
Whether your roof is suitable for solar panels depends on a few different factors. The angle at which your roof is facing is probably one of the most important things to consider here. The reason for this is certain roof angles will generate more solar power. The more sunlight your roof receives, the more solar energy your panels will generate.
Your roof might not be suitable for solar panels if:
- Your roof is too old
- It’s not at an optimal angle
- Your roof is made from wood
- Little to no roof space
- Your roof is too shallow or too steep
To install solar panels on your roof, it should be structurally sound and not made from any fire hazardous materials like wood. There should also be ample space to install your solar panels, and this will be checked at the quotation stage.
Ideal roof angles for solar panels
The ideal angle for rooftop solar panels is 35 degrees. (Image credit: Adobe)
Most roofs can accommodate solar panels and generate a reasonable amount of energy. However, there is an optimal angle for your solar panel system.
It should come as no surprise that solar panels function at their most optimal depending on the time of day and season. With that being said, in order to get the most out of your roof solar panels you’ll ideally want them to receive the most sun throughout the day.
In order to do this, you’ll need to know which way the panels should face and what the optimal tilt angle is.
Optimal roof angles
According to Viridian Solar. your solar panels should be south-facing and tilted to a 35-degree angle from the horizontal. This maximises the energy collected by the solar panel and is the most beneficial angle in order to help you save the most on your energy bills.
Source: Microgeneration Certification Scheme (MCS) guidance for domestic solar installations
The above table clearly outlines the optimal angles for roof solar panels, with the percentages representing how much of your panels’ total potential output you’re likely to achieve based on the angle of their tilt and the direction they are facing. This is a helpful guide to better understand if your roof is optimally oriented. As you can see from the table, the more west or east facing your roof is, the more output your system will lose.
The further your roof moves away from south facing, the lower your system’s output will be. Even if you have a southeast facing roof as opposed to due south, this will decrease your output by 5%. The amount that your roof slopes is just as important to which way it faces. It’s most optimal for your roof pitch to be between 30 degrees and 40 degrees, which gives you the most output.
What type of roofs do UK homes have?
A typical UK home’s traditional roof pitch measures between 30 degrees and 50 degrees, according to Marley. If your roof’s angle is 30 degrees or less, it is considered a low-pitch roof and anything less than 12.5 degrees is considered a flat roof. Ideally your roof should be between 30 degrees and 40 degrees, as this gives you the maximum output from your solar panels.
Roof materials commonly fitted in the UK are:
Some roof materials are more suitable for solar panels than others, according to Roofer UK. and some are not suitable at all for safety reasons. So if you’re wondering if your house is suitable for roof solar panels, the below table should help you decide.
How to measure your roof for solar panels
You can measure the angle of your roof to decide if it’s suitable for solar panels. (Image credit: Adobe)
It’s important to know the angle of your roof. How much it slopes, or doesn’t, will affect how much energy your solar panels can generate. It might even influence your decision to install solar panels all together. We’ve put together a guide on how to measure your roof for solar panel installation below.
To measure your roof’s angle you’ll need:
One way to measure your roof would be to climb up to it with the above equipment, but there is a safer way to measure your roof’s angle.
The easiest way to measure your roof’s angle is surprisingly from inside your loft. Follow our step-by-step guide to help you do this.
- Take your spirit level into the loft
- Position your spirit level so that one end is touching the rafters (sloped wall of your roof)
- Holding it level, measure the distance 12 inches from the rafter going up the wall
The measurement you have now is the amount your roof rises every 12 inches. So if your measurement was nine, that would now be 9:12, which is how much your roof is expressed by. You’ll now need to convert this into degrees using the formula below.
- Divide your measurement by 12 (e.g. 9/12=0.75)
- Input this number into a scientific calculator, such as the one here. and calculate the arctangent (e.g. the arctangent of.75 is 36.869897645844)
- Round this number and the result is your roof angle. In the above example, the angle would be 37 degrees
Can solar panels be installed on a flat roof?
It is possible to install solar panels on a flat roof, but it may require special mounting rails. (Image credit: Adobe)
The short answer to this is yes: There are ways in which to install solar panels on flat roofs, such as by installing special mounting equipment. However, this doesn’t mean they will be highly effective, nor are they likely to have a low power output.
- Panels need to be self-cleaning
- Thin film solar cells work better than traditional solar panels
- The pitch of the solar panels should be carefully considered
It’s important that solar panels on a flat roof are able to self-clean during rainy weather and avoid damage during adverse weather conditions. If you consider that a typical roof pitch is 35 degrees, rain would naturally run downwards and not cause dirt to build up.
Thin film solar cells, although not as effective as crystalline solar panels, are incredibly flexible and work well on flat roofs. You may also opt for moving panels over stationary ones. This type of panel moves with the sun throughout the day, ensuring your panels capture as much daylight as possible.
Solar panels should be pitched between 20 degrees and 50 degrees on a flat roof in order to catch maximum sunlight and generate a feasible amount of solar energy. This will also help them to be self-cleaning and free of debris.
Can solar panels protect your roof from damage?
There’s a myth surrounding this topic claiming that rooftop solar panels can damage your roof. It’s actually quite the opposite, providing your roof is in good condition and the solar panels are installed correctly.
As well as a lot of attractive renewable energy benefits, solar panels can protect your roof from damage from factors such as:
Solar panels provide a small layer of protection for your roof from bad weather. Extreme weather such as snow, hail, heavy rain, and wind can cause damage to your roof over the years. When solar panels are attached to the roof they can block some of the adverse weather, and in theory your roof could last longer.
Roof solar panels also have a cooling effect. By absorbing the sunlight that would otherwise penetrate your roof without solar panels, they keep temperatures down. There’s also a small gap between your solar panels and the roof, which allows airflow and creates a shaded layer of protection from the sun’s rays.
It’s a common misconception that rooftop solar panels can leave you with unwanted and unsightly holes in your roof. According to the Federation of Master Builders ( FMB ), solar panels are installed using anchors. A few tiles are briefly removed for the anchors to be inserted into the roof and are put back without any damage if installed properly.
Do you need planning permission to install solar panels?
There’s no straight answer to this question, as it will depend on the size of your solar panel system and where you live. As mentioned by FMB. most solar panel installations do not require planning permission. Although, you should let your home insurance company know since solar panels are a structural element added to your roof.
There are some instances where planning permission may be necessary. If your home is Grade II-listed or you live in a conservation area then you may need planning permission.
You can check your local authority’s planning rules here.
The future of rooftop solar panels
Solar energy is becoming increasingly popular as the UK moves towards ensuring cleaner power is more readily available. Like with any new technology, the amount it costs usually decreases over time. One of the main stumbling blocks for solar power at present is cost. A typical 4 kW solar panel installation is around £6,500, and for most that is a costly sum.
With that being said, the future of solar is promising and in the years to come the investment may become less costly.
Could your roof be covered entirely with solar panels?
It’s possible to have solar panels spanning the entirety of your roof. This maximises the amount of solar power that you will generate and in turn should save you more on your energy bills. With that being said, your roof would need to be thoroughly assessed to make sure it is structurally sound just like when you’re installing only a few solar panels.
Solar roof tiles
Solar roof tiles are available on the UK market, but they’re not as efficient as solar panels. (Image credit: Adobe)
If you’re concerned with the aesthetic appearance of solar panels, then solar roof tiles could be another option to consider. Solar roof tiles are small modular tiles that can be attached to your roof. The appearance is somewhat more attractive than traditional solar panels. Solar tiles blend in with your existing roof tiles.
The main difference between traditional solar panels and solar tiles is their efficiency. Solar tiles generate less power, and the cost is higher than that of solar panels. Solar roof tiles cost up to three times as much as solar panels, which could mean paying £10,000 to £12,000 for a 3 kW solar tile system, according to The Switch. A solar panel system of the same size is around £5,000.
- Solar tiles are eligible for the same government grants as traditional solar panels
- aesthetically pleasing
- Can increase the value of your property due to the rising demand for renewable energy
- Cannot be installed on existing roof tiles so it is more suitable for new buildings
- You would need to replace existing tiles with solar tiles
- costly than traditional solar panels
Solar roof tiles are still relatively new to the market, and for this reason won’t be a viable option for most cost wise. This is more of a good option if you’re looking to generate solar energy but are hesitant to have unsightly solar panels on your roof.
Solar panels for car roofs
As you most likely already know, the UK is pushing ahead with its plan to ban the sale of new petrol and diesel cars and vans by 2030, with the aim of only selling zero-emission vehicles from 2035. Electric cars still need to be charged, either at home or via a charging point. Now, if you were to charge your car at home, you would most likely see an increase in your electricity bill.
This is where solar panels for cars could be the future. In fact, many automobile companies are working towards making solar-powered vehicles, according to Interesting Engineering. Solar-powered vehicles are electric and use photovoltaic cells on the body of the vehicle to convert energy from sunlight. The vehicles can store a small amount of energy, allowing them to run at night time or on cloudy days.
However, don’t get your hopes up just yet. Buyacar sheds some light on why the idea far surpasses the current technology. Roof solar panels on cars unfortunately don’t generate that much electricity. Currently, the solar panels on cars are mostly used for powering the air conditioning, radio, steering, and sat-nav, and don’t provide enough energy to charge the car’s main battery. Still, this is a great way to generate free electricity and boost your car’s battery should you have an electric car.
Rooftop solar panels FAQ
What roof angle is best for solar panels?
The best roof angle for solar panels is between 30 degrees and 40 degrees. In order to generate the maximum amount of solar energy, your roof would ideally be south-facing at 35 degrees.
Do solar panels work in the winter?
Solar panels work through all four seasons. However, they do tend to generate more solar energy during the spring and summer months thanks to the longer daylight hours.
Is my roof suitable for solar panels?
This depends on various factors. Your roof should be structurally sound and not made of a fire-hazardous material such as wood. If you have a flat roof, low angled roof, or a roof that’s not south-facing you can still install solar panels. But, you should know that your panels are likely to generate less solar energy than if they were at the optimal 35-degree angle.
How much do solar panels for roofs cost?
The cost of rooftop solar panels depends on a number of factors, so it can vary from installation to installation. However, as a guide price, you can expect to pay around £6,800 to £8,000 for a typical 4 kW system, which is usually big enough for a household of three to four people. For a full analysis on solar panel costs, read our guide here.
How long do rooftop solar panels last?
If solar panels are kept clear of dirt, dust, and debris regularly, they can typically last upwards of 30 years. While solar panels can still function beyond this point, their efficiency will start to degrade every year, though most manufacturers on the UK market say their panels will still have 85% to 90% efficiency after 25 to 30 years.
Are solar panels bad for your roof?
Many homeowners who are researching solar panels may wonder whether adding a system can actually damage their roof. While the installation process does require drilling into the roof to install the mounting rails, when done by a professional this will not cause any damage. If you do experience any leaks or other problems after your solar panels are installed, you should contact your installer immediately to rectify any damage.
In fact, as mentioned earlier in this article, solar panels might even go some way to protecting your roof from damage, as they can act as a barrier to harsh weather conditions.
Are solar panels too heavy for roofs?
Provided your roof is in a good state of repair and your house is structurally sound, solar panels should not be too heavy for most roofs. As solar PV technology has advanced, panels have become lighter over time—but remember that the typical system needed in the UK consists of 12 to 16 panels. However, this question highlights why it’s so important to seek a reputable installer for your solar panels, as they will often carry out a survey of your home during the quotation process to ensure the structure can safely handle the weight of a solar panel system. Proper installation of the mounting rails is also key, as this will prevent any damage to your roof and ensure the panels can withstand high winds.
What are my options if my roof is not suitable for solar panels?
Solar panels don’t always have to be installed on roofs, although it is the preferred option because it optimises the amount of sunlight that hits them and saves space. If you’re keen to switch to solar power but have been told your roof is not suitable for solar panels, you can opt for ground-mounted systems. However, due to the amount of panels needed to power the typical household, you would need a lot of ground space to accommodate the system. For this reason, you will likely need to seek planning permission from your local authority, particularly if the resulting structure is larger than 9 square metres or more than 4 metres high.
Roof replacement with solar panels
Solar panel systems will typically last around 30 to 35 years – and in that time, your solar panels will generate plenty of savings on your electric bills! These systems have very long lives, which leaves many homeowners wondering about the impact they will have on their roofs: how will the roof hold up over time? What happens if you have to replace your roof after installing solar? Should you just replace your roof at the same time you install solar panels? In this article, we’ll explain what you need to know about replacing your roof when going solar.
Should you replace your roof before installing solar panels?
Before you install solar panels, consider requesting a roof inspection to make sure it can withstand installation, especially if the roof is towards the end of its life. If your roof is between five and 10 years from needing replacement, it’s a good idea to get an expert out there to assess.
Most solar companies don’t offer roofing services, although there are some exceptions. Either way, roof work is commonly performed alongside a solar installation and your solar contractor likely has good referrals for roofers in your area – they may even be able to get you a discount on your roof replacement.
If your installer determines that your roof should be replaced prior to going solar, it’s a Smart move to do so. Solar panels are more durable than most roofing materials – so, when you pair solar with a roofing installation, the panels actually extend the lifetime of the portion of the roof that they cover.
The other benefit of pairing solar and a roof replacement together is that if you’re installing on a new roof, it’s unlikely you’ll need to re-roof during the lifetime of the system. This can help save you money in the long run because you’ll avoid the costs associated with removing and reinstalling the solar panels on your roof.
How much does a roof replacement and solar panel installation cost?
In the case that you do need to replace your roof prior to installing solar panels, you’re likely wondering how much your solar panel installation will cost. The average cost to install a new solar system in 2022 is 20,000 before rebates and incentives (like the federal tax credit), based on EnergySage Marketplace data. The average cost to replace a roof is about 10,000, according to This Old House. Therefore, you can expect an average new solar system installation and roof replacement to cost about 30,000. However, you may be able to knock a significant amount off of that price if you opt to combine the two larger costs. You can save up to 30 percent off of your new solar system with the federal tax credit and may be able to receive discounts on the roofing costs if your local roofing contractors or solar installers have partnership agreements to offer customer discounts.
How much does it cost to remove solar panels to replace your roof?
If you run into a roofing issue and need to replace your roof post-installation, there will be labor costs associated with taking the panels off your roof and putting them back on. Unfortunately, it’s hard to give specifics on the costs associated with this labor, as it can vary greatly. Installers will have different rates for their labor and the cost can also vary based on the size of the system, how many panels will need to be removed, and whether you need a place to store the equipment.
If mounting hardware also needs to be removed in order to replace your roof, this will add onto the cost. On average, residential installations tend to cost somewhere between 1,500 to 6,000 to remove and reinstall. (This is not inclusive of the cost required to replace your actual roof.)
If re-roofing post-installation is a concern for you, it’s always good to ask your potential installer how often they do this type of work, and the typical cost associated with it. Some companies will actually specify a price for this in your initial contract, and it never hurts to request this from your company prior to installation.
Do solar installation warranties cover the roof?
Roofing issues caused during the installation process or overtime are uncommon, but many solar installation companies often have warranty coverage for your roof where the panels are located in case you need a roof repair. Many companies do this because it’s common for existing roofing warranties to become void if you’re installing solar, at least for the portion of the roof where your system is installed.
The typical duration of this type of warranty is 10 years, but it can vary from company to company. Before you sign a contract, confirm with your installation company whether they warranty the roof and the duration of that warranty.
Should you install a solar roof?
Solar shingles or building integrated photovoltaics (BIPV), like the technology offered by Certainteed or Tesla, are certainly more attractive if you have to re-roof. The solar tiles or shingles will replace the roofing material itself, so you won’t need to spend money on both and can still generate savings on electricity.
Is going solar still worth it if you need to replace your roof?
An average solar installation will save homeowners tens of thousands of dollars on utility bills over its lifetime while generating clean, renewable energy! Re-roofing costs can be high, but the savings of using solar power should make up for it in the long term, especially with rising energy costs – and there’s no better time to evaluate solar if you were planning on re-roofing anyway (those panels love new roofs!). Many homeowners find that they receive discounted rates from roofing companies that have existing partnerships with solar companies, and you could save as much as 30 percent on roofing costs if you replace your roof and install solar at the same time.
If you think that you might be moving in the future, you might be worried about putting money into a new roof and a solar system. But that shouldn’t be a concern: if you go solar at the same time as replacing your roof, you’ll also likely increase your home’s resale value. A new roof already improves the value of your home, and many homebuyers are looking for electric and environmentally friendly homes, making your solar system very attractive!
Start shopping for solar today
If there’s a potential solar installation on your horizon, try out our Solar Calculator to get an estimate of potential costs and savings, or use the EnergySage Marketplace to get competitive quotes for solar installations from local and certified installation companies specific to your home. If your roof is on the older end, you can note this in your account. EnergySage installers can give you advice on potential roofers to contact, or sometimes even do the work themselves.
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