Solar Roofing – Flat and Metal Roofs with Integrated Solar Panels
In this article we will discuss solar roofing systems, which integrate roofing materials with solar PV panels or solar thermal systems. Specifically we will cover, metal roofs, PVC flat roofing membranes and asphalt shingles. Although most roof-mounted solar systems are installed on top of an existing roof – be it an asphalt shingles roof or any type of flat roof – these solar systems are not integrated into the roofing material, and therefore are not solar roofs.
Why Are Solar Panels Installed On Roofs?
Most solar systems are installed on a roof of a house or a building. The exception are solar farms or ground-mounted solar installations, but these are rare, and are usually 100% commercial solar systems. There are a number of reasons why most solar systems are installed on roofs. The primary one being limited space – especially in an urban setting, where roofs represent significant unused space. Another reason is that usually roofs are not shaded by trees, nearby buildings, etc – they are the highest point of a building with great sun exposure, which makes them perfect to install solar panels on.
What Is a Roof-integrated Solar Systems?
Solar roofing is a final product, which integrates solar panels with the roofing material suitable for either a sloped or a flat roof. The solar panels used in solar roofing are usually thin-film photovoltaic laminates. Most popular Solar PV laminates commercially used today, are the Unisolar thin-film PV panels.
Unisolar thin-film PV laminates were originally designed to fit into and be integrated with standing seam metal roof panels. Unisolar panels are 15.5 inches wide and fit perfectly into a 16″ standing seam panels, and are attached or laminated with special butyl adhesive that is on the back of each Uni-solar PV panel.
However, unlike with metal roofs, solar integrators were having flat roof leak repair issues with solar systems they installed on flat commercial roofs. After they installed solar mounting racks and attached them to the roof deck, the fasteners would start leaking after a while.
Roofing manufacturers adressed this issue with different versions of flat roofing materials that integrated Unisolar PV panels – one such system is IB Solar Roof. There are many types of both solar metal roofs and solar flat roofs, using solar PV panels from various manufacturers (though as I said, most do use Unisolar PV laminates).
Solar Metal Roofing
The most common type of solar metal roofing is the standing seam metal roof with integrated Unisolar PV laminates. Unisolar PV laminates were initially designed to fit in the pan of standing seam panels, with the connection terminals concealed by the ridge cap. Because the connectors or terminals of these PV panels are not UV stable, they need to be hidden from the sun, while the rest of the panel is of course exposed to the sun to generate solar electricity.
The benefits of standing seam solar metal roofing include fast installation, easy troubleshooting, and lifetime leak free roof performance. Additionally, in the US, you can get the 30% solar tax credit for installing a metal roof, as it is a part of the solar system.
Solar Metal Shingles
Another type of solar metal roofing would be solar metal shingles. The concept is similar to solar standing seam roofing, but since metal shingles are much smaller, the solar PV laminates have to be adjusted to the size of the shingle. Also, all the terminals must be connected during the installation – if you miss just one, the circle will be broken and the solar system will not work. Imagine finding the broken link when you have hundreds if not thousands of metal shingles to take off to find one broken connection!
Price-wise, I think that standing seam solar metal roofing is much more viable, as there is substantially less installation labor involved and much less potential troubleshooting, if something goes wrong. Imagine hiring a solar integrator and a professional metal roofer at 75-100 per hour – each – to find what is wrong with your solar metal shingles roof. Even if everything is peachy, the amount of time that will be used to install solar metal shingles is much more than that of a solar standing seam roof. The total solar system price will be significantly higher just from all that extra labor.
The bottom line is that the choice of solar metal roofing system that you decide to use will be more of a personal preference. Both will work great when professionally installed, and will last a very long time.
Solar Flat Roofing
The main reason why flat roofing materials manufacturers began developing solar flat roofing systems was to A) eliminate roof leaks associated with flat-roof solar installations, and B) sell more flat roofing materials, which is their main business after all.
Solar Flat Roofing is a great concept, but has some limitations. First, the angle on the solar panels is flat, so these panels will not catch as much sunlight as tilted or sloped solar panels. Second, solar flat roofs will be much more effective in warm climates vs. colder northern climates such as New England, as in the winter, flat roofs are completely covered with snow and sunlight does not get through to the solar panels.
That said, the benefits of solar flat roofs far outweigh their drawbacks in colder climates. The solar PV panels that are integrated into the roofing membrane eliminate 99% of roof penetrations, considerably reduce the weight of the solar system and the total solar system price. Not only are the solar panels lower for roof-integrated solar systems, you also eliminate the entire rack-mounting system (which costs about 1 per watt of your solar system) – and that is not small beans – you will save about 10-15% off your total solar system cost. Also, since the roof solar system weighs much less than regular solar panels mounted on racks, you also eliminate substantial weight, and your building construction costs will be much less, because you can reduce roof load requirements.
Solar Asphalt Shingles
Solar asphalt shingles are very similar to solar metal shingles described above. The main difference is that they are designed to work with 3-tab or architectural asphalt shingles instead of metal roofing shingles.
Although solar shingles may seem like a great concept, please consider the following factor, which makes them not such a viable option when it comes to solar roofing. Solar shingles, just like metal solar shingles, take a very long time to install, as each shingle must be connected to the rest of the solar system in the series. However, unlike solar metal roofing shingles, there is no room to conceal the terminals under the shingle, so all connections must take place inside the attic space. Holes must be pre-drilled for each shingle, and terminals are fed inside the attic where they are connected.
This slows down the installation process significantly, and usually you cannot finish this in one day. If it starts to rain, your roof is toast. There are too many penetrations under the solar shingles, and it is very easy for water to get in. Of course, there are ways to prevent the roof from leaking even if it rains and the roof is not finished. You can run the last row of shingles and overlap it with roof underlayment, which will prevent the roof leak. Still, this makes the total job that much more complicated and costly.
One more thing to consider is the fact that asphalt shingles only last about 15 years and will have to be replaced down the road, where as a metal roof will last pretty much forever, or at least the lifetime of your house.
Solar Roofing Resources
Solar System Guide – everything you need top know when designing a residential Solar PV system – positioning of your roof toward the sun, shading and angles of your solar panels, choosing the solar panels and inverter, etc.
Metal Roofing Materials – learn about different metal roof types and which metal is better to use – steel, aluminum, copper, zinc, etc., as well as learn more about metal roofing prices.
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There are two building-applied solar veterans that make what they call solar shingles but may be better described as small, rectangular solar panels that are installed without traditional racking systems.
Solar roofing is going to be the new age standard pretty soon and it ought to be. Anything we can do to for a greener living is vital at this point.
Solar roofing is becoming more and more poplar and providing a green solution to our environmental issues. I enjoy educating folks about this as its a dual benefit and better for everyone.
Solar system integrated with the roof is the one for the future, infact a start has already been made with the advent of solar shingles but currently a bit expensive but in future rates are sure to come down.
Solar roofing is future with so many environment friendly products coming up and government is also giving impetus in the form of tax relief that in coming years, with better technology, will come down and solar roof would be more prevalent than they are now.
Having solar panels on the roof is the best utilization of the roofing space, lots of energy is saved and lower energy bills during extreme weather. Solar shingles launched by Tesla is a great move in that direction, though currently very expensive but with time, are certain to go down.
With the brisk innovation in the field of solar energy, cost of solar equipment has gone down and with innovations like solar shingles, it has become very easy to install an effective, stable and complete solar system on your roof.
Very informative article, installing solar panels on the top of the roof not only reduces your energy bill, you can sell back extra energy back to the grid. Tesla has just launched solar shingles, which will not only protect the roof but also generate electricity!
This is always a great idea to do a solar roofing. This article is nicely described about solar roofing in various different roofs like flat and metal roof. Save energy and Use Solar roof.
Having solar panels on the roof in the locations where there is a history of sunlight for a long period of time is a great idea, very eco-friendly and cost effective in the longer run. But I am curious to know, do these solar panels survive hail storms?
It looks like most Комментарии и мнения владельцев stopped about 3 years ago. I’m building a house near Raleigh, NC that will have a metal roof and I’d love to incorporate solar. However, I hate the look of the bulky solar panels, but it seems that the laminates weren’t all that great. So now it’s 5 years from the original post and 3 years since the last one. Where has the industry evolved to and who, if anyone, is producing good quality, efficient solar laminates panels?
Hi Tim, The company that manufactured these laminates (UNISOLAR) filed bankruptcy a few years ago. While their products still sell, I’m not sure who will take care of warranty if any issues arise. At the same time, I have not heard of any real issues with UNISOLAR panels. And if you can find them now, they should not be that expensive (compared to how much they cost 3-5 years ago). If it were my home, and I could get these at 1-1.50/Watt, I would not hesitate, even though manufacturer is out of business. On Amazon they sell these panels for about 224 for a 136 WATT strip. =Back in the day, these used to be 3.50-4 / watt. You can also call some Solar suppliers to see if they have some left. I know Soprema – a large roofing manufacturer – had a deal with Unisolar 5-6 years ago, and had purchased over 1 million watts of panels, and then had to sell them for pennies on a dollar, because regular solar panels dropped in price dramatically. There was another (Chinese) company that manufactured similar laminates with higher efficiency. The company or product name is Xunlight. However, I’m not sure about their reliability or quality. I recommend you do some research about this. I will also ask a few people in the industry.
Tim, The CIGS thin film laminates by SoloPower are the latest technology. the SP-1 is similar in dimension to the Unisolar panels with twice the power density.
Dear Sir/Madam. Sunny greetings from Malaysia. 1. Is your company represented in Malaysia or in the Asia – Pacific region ? 2. What are the types of PV panels and laminates does your company deal with – the country of origin. quality certification, warranty and other relevant information would be useful? 3. Would your company be interested to collaborate in setting up a joint- venture set-up in this part of the world? Your kind understanding and co-operation in this matter is most appreciated. Thank you. Best regards M. Wee
Hello how are you today ? This is jeff I would love to know if you can do perfect job for my Full Roof Replacement also let me know if you accept visa/master card as mode of payment.
Solar roofing is something that should be a viable option to anyone who is looking to replace their roof in the near future! The idea that you can use otherwise wasted space to generate some extra power for your home is a great idea. The commercial roofing in Hawaii is one of the best places to view how well this works! There are homes all over that utilize this technology because of the gorgeous weather that we have here!
The last thunderstorm we had really took a toll on my roof and now it leaks. I was looking for a bucks county roofing company to see if they will fix it but I really like the solar shingles you mentioned. If I have to replace my roof anyways I might as well go big. Can any roofer install them or do you need a special person? What kind solar roof would you recommend?
Those solar shingles look like a great solution and aesthetically speaking, it looks good as well. I wonder if it is as efficient as the other solar panels. I will definitely consider using them.
Daniel Blair, On pg. 4 of IRS FORM 5695 it also says before that: “any labor costs properly allocable to the onsite preparation, assembly, or original installation of the residential energy efficient property and for piping or wiring to interconnect such property to the home.” BIPV/TIPV can be part of the roof or any part thereof. If you wish to circumvent damaging rack penetrations even if it were a potentially more expensive comprehensive system, you have no cap limitation and there exists no power output requirement. There is great latitude to invest what you want on your home regardless of expense.
Daniel Blair, Wouldn’t you have to have money to short a stock? ECD FAN doesnt have money because he has no job! Thats why he has all the time in the world to piss every one else off! He,he,he
@ Dan, Thanks for the followup. I read the form and you are correct this is what I have been looking for, but it is not as “clear” as you claim. Per the form: “Qualified solar electric property costs. Qualified solar electric property costs are costs for property that uses solar energy to generate electricity for use in your home located in the United States. This includes costs relating to a solar panel or other property installed as a roof or a portion of a roof. The home does not have to be your main home.” @ ECD: I have seen you all over the web trolling. Ok we get it, you hate PV systems and you think it is all one giant scam. There is possibly “zero watts” of connection between Solyndra going bankrupt, getting raided and the tax credits that I asked about. I have listened to your advise after doing some research about Unisolar ECD and I now refuse to use their product on my home. The original poster is correct that almost every laminate here on the east cost is Unisolar so your market analysis of CA has zero bearing to the discussion. It will be interesting to see if you are right about ECD going bankrupt in a year. If you are confident have you shorted their stock to profit off your insight?
ECD FAN knows doesnt know anything about roofing. This solar nerd is lost when solar evolves into more simplified designs becoming an integral part of a roof. This is the realm of the roofer and it will stay this way as more roofers from all over take up interest in hooking up solar. Heres what the Florida Construction Industry Licencing Board had to say on August 12, 2011 about TIPV: ALEJANDRO ARGUELLES – PETITION FOR DECLARATORY STATEMENT Mr. Arguelles was not present but was represented by his nephew. Mr. Biggins presented this case stating Alejandro Arguelles filed a petition for a declaratory statement on July 14, 2011. The petition was noticed in the Florida Administrative Weekly on August 5, 2011. Mr. Biggins noted that the petition requests interpretation on Section 489.105 (3)(o), Florida Statutes, and whether a licensed general contractor must be a certified or registered solar contractor or contract with a solar contractor in order to apply Tile Integrated Photovoltaics to roofing. Mr. Biggins asked the board to consider whether or not the petition meets the criteria for a declaratory statement, and to dismiss or answer as appropriate. After discussion the board determined that the petitioner is a substantially affected party and that the petition had standing. After further discussion the board voted that the license categories all Division I contractors and Roofing contractors can install the product listed in paragraph 2 of the declaratory statement. http://www.myfloridalicense.com/dbpr/pro/cilb/documents/cilb_minutes_0811.pdf As you can see, the days of Chinese traditional c-Si solar panels on racks and leaky penetrations are nearing a close! He,he,he Homeowners will want more integrated systems because they just make sense! Dan
Daniel Blair, You will have to forgive me for not introducing ECD FAN, he is the resident internet basher that fabricates lies and spews vitriol 24 hrs a day without the need for compensation. His real name is Robert V Bauer, self proclaimed “Polymath”. That means a “Mr. Know-it-all” for the rest of us mere mortals. You can read about his early departue from Unisolar here: http://www.linkedin.com/pub/robert-bauer/8/124/768 You can read here what a Solar Engineer from Twin Creeks thinks about this anonymous coward: Time to repeat this John Foreman 02/28/10 5:24 PM ” If you guys notice, ECD.Fan tries use arguments of Uni-Solar’s low power density (6%) and integration design mistakes, to apply this as is the “whole BIPV” industry / market is perpetually doomed… despite CIGS thin-films now reaching c-Si efficiencies and I bet if they had the same “economies of scale” applied to their industrial processes, would and will drop way below c-Si in terms of /W. Even with the small amount of rare-earths used, no different than the rare-earths used in his favorite thin-films CdTe based from first solar, which had Walmart to help them scale. Plus he always ignores that no one wants, hundreds of roof penetrations, heavy racks, heavy modules, weighing their roof down. Uni-Solar led the way with inventive form factors (1st generation), including their failed SHR-17 shingle product. Dow’s powerhouse shingles share little in common 1.) double the power density, 2.) far less wiring (their tabbed shingled interconnect and self-ground). 3.) uses the best CIGS cells from Global Solar at 13-15 efficiency depending upon if one speaks of aperture or cell efficiency. 4.) He ignores the labor and integration savings to be had by a winning BIPV product… whether it be nail-gun installable shingles, laminates with better adhesives for metal roofs and laminates. If you notice also, anytime anyone posts any news release on PV thin films (now including CIGS, or any other technology)… he’ll be the first to come in and trumpet First Solar and CdTe in panels and big Silicon. He has a horse in the race, because if you do your research it’s been leaked he’s close to NY/Russian fund managers. Russians have a lot of poly-Si facilities, so it’s obvious his motives. If you google “ECD.Fan Todor Mitev” you will find he is likely linked (or is) Todor Mitev of the Temujin Fund. Which means he has a horse in the race to use Uni-Solar’s woes to try and short any up and coming technology like CIGS at 11-15% efficiency and rising. He is a fund manager, who does nothing but blog all day, so be VERY skeptical of his arguments for sure. He can post lots of numbers and always calls out people (attempting to squash their thoughts). Don’t buy into his vitriol. FYI – I’m not a fund manager, just an engineer / scientist sick of seeing this guys ill-conceived posts all over the place that misguide the public in a direction he wants. In fact his blog-spot is now closed to the public and he’s been kicked off the ECD board on Yahoo (ENER). Probably by court order. ECD FAN has a a dishonest agenda…. Dan
Daniel Blair, I never recieved an answer on this from Leo or Admin. Check out IRS FORM 5695 its very clear. If your new flat roof is done at the same time as your thin film installation, the 30% fed tax credit includes the roof because the new roofs acts as an anchor for the thin film. It also says that you can rely on a certified manufacturer statment that the roof qualifies and you need only keep it for your records. This is without cap limitation and is not limited to the solar footprint. Thats why it is called BIPV. BUILDING INTEGRATED PHOTOVOLTAICS.
Daniel Blair: Mr. Dan Arguelles is a well-known rip-off artist (just google for ripoff and Artezanos), so you should believe anything he says at your own risk. Plus, he has zero Watts of grid-connected rooftop PV systems installed (his proposed installations are illegal). A company called Solyndra (now bankrupt) also claimed to have received an IRS ruling regarding their “roof-integrated” PV system – but FBI recently raided the homes and offices of its management, so you should take that tax credit claim with a grain of salt as well. I suggest you hire a reputable tax attorney and ask her to give you an opinion in writing (or, even better, to help you obtain an IRS “ruling”) regarding your question. So when IRS comes after you, you know who to sue!
Admin or Leo, As a followup to Dan’s question above, I have been told by multiple sources that thin film solar laminate adhered to a new flat roof membrane installation (solar roof) allows for the roof and PV system to both be eligible for the 30% tax credit just like the metal. 1. Is this correct? 2. Is there written evidence for this? I have checked the DOE and IRS and I have found no documentation for this claim.
@ Rodney I sent you an email. Also please provide brief description of the product, and a website where more information can be found.
My company (US owned and manufactures our products in US) makes solar integrated shingles for home and business. We also have a flat roof system.Our products are warrantied for 90 years and are fire, wind hail, snow proof and are very light weight. Please contact me.
I too am wondering the benefits verse the cost of installing solar roofing in parts of the country where there is less sunlight due to either weather or climate. It seems like a no brainer in areas like Florida but say northern Maine or Michigan I’m not so sure
I have been studying solar roofing for the last week. Sorry, I just got started on the subject. Anyhoo, here is my general question. I live in a condo in Charlotte, NC that has very strict regime / HOA rules. What options can I use to combine solar to my condo. My HOA allows TV dishes, so I am hoping to find a solution that is small yet powerful. I have looked at solar generators such as the Powerhub 1800, but I am just not sure based on my situation. Yes, I realize that my question doesn’t really match the article about ‘roofing’ but I am hoping you have a suggestion based on your knowledge of solar overall. Also, this is another important question. Does solar roofing work ok in the winter in areas such as mine where the winter months are consistantly overcast? We dont get alot if any snow in my immediate area, but we also don’t get alot of direct sun from November to March.
ADMIN, Seems like there are some questions that are looking for answers. Would you be so kind to answer mine? Dan
Sorry, I guess the next question is whether you have a UK distributor or outlet I can explore feasibilities and costs with?
Am a UK based installer and struggling to find a flat roof mounting solution that does not require making the installation sink into the ground due to the amount of ballast required or having to pepper the roof with holes. So the flat roof option you present is interesting and logical, however being flat what are the implications for cleaning? At 30 degrees most panels are considered ‘self-cleaning’ but the inclement weather in the UK makes for frequent ‘dirty’ rain. And the local birdlife doesn’t much help. So a flat panel may struggle a bit. Thoughts?
Leo, I think my question is relevant to solar roofing. Can you please answer my question? Do you have a documented example of a metal roof with PV thin film qualifying the entire Metal Roof investment for a 30% Federal Tax credit as “Qualified Solar Electric Property”? Thanks ahead for your answer! Dan
Leo, Can you please give some examples of a job that was 30% Federal Tax Credit for the whole metal roof with some PV Laminates on it? Have you seen this done yet? Dan
Wow Leo, you are a prime example of why people from your neck of the woods are so disliked here in Florida. What total arrogance. I ask a simple question about how my guys will have to CLEAN those solar roofs someday, and you take my head off. Click on the website in THIS link, and see what I represent. I am FAR from Spam. I am a roof cleaner in Tampa Leo. How will “advertising my website” help me in your neck of the woods ? The jobs we do here in Florida average between 2 and 400 dollars, hardly enough to drive to your neck of the woods and back, EH ?
Chris – this has nothing to do with me being arrogant. I think you do know that algae does not grow on solar panels. Most you will get is dust / dirt, which is washed off with water. Therefore asking how to clean algae off the solar panels is “spam” in my opinion. Your comment was “irrelevant” to solar roofing, in the way you’ve presented it, and appears as advertisement, with no useful information to add to the topic. As far as you driving up to Massachusetts – I never suggested that – placing link to the website advertises your company, and not only in MA – our blog is read everywhere in US, and Florinda is in the top 5-7 states when it comes to number of site visitors. I assume that you are a Smart man, and I will not engage in the “How will “advertising my website” help me in your neck of the woods ?” discussion – we both understand that this is about sticking in the link to the website. Chris – It’s not personal – I just think that if I do approve comment, it has to be valuable to site readers – not promote someone’s business. If you do post a comment that is about the topic of the post, i will approve it with the link. Here is an example – on our roofing job profile in Lowell MA (https://www.coolflatroof.com/flat-roofing-blog/roofing-lowell-ma/) – you left a comment saying your uncle lives in Charlestown, where we did a restaurant roof for him. We never did a restaurant roof in Charlestown. So explain the nature of that comment to me please. BTW, the comment links are are “nofollow” and have little benefit for you. If you want – write a post about”green” roof cleaning, and how it can extend the life of the roof, which will benefit the environment (in terms of not throwing shingles into the landfill, until they reach the end of service life), and I can post it for you with the reference to your site and your credentials.
I think the Solar integration is a great idea. Might as well use free energy from the Sun. I don’t know much about solar panel efficiency, but can’t imagine it will work well with Roof Algae Growth blocking the suns rays from the solar panels ? This means these roof will require cleaning. This is my interest in them, since I head the Roof Cleaning Institute Of America where we train, and certify roof cleaners. Our men will encounter these roofs one day, and I would like to know what they are made out of, to determine the best way to instruct our students to clean them.
Hi Chris, How is this relevant to solar roofing? I get it – you want to advertise your roof cleaning business. However, if you want to post meaningless Комментарии и мнения владельцев, I will remove your website from it. If you post something worthwhile – your website will be displayed. Bottom line, we closely moderate our blog, and do not want spam.
Admin, You claim early on that a thin film solar laminate on a standing seam roof would qualify for the 30% Federal Tax Credit as well as the metal roof. “The benefits of standing seam solar metal roofing include fast installation, easy troubleshooting, lifetime leak free roof performance, and in US, you can get the 30% solar tax credit for the metal roof also, as it is a part of the solar system.” What evidence do you have to support your information? Thanks, Dan
Solar Metal Roofing is an integration between a roof and a solar PV system, where metal roof acts a support structure for the solar panels adhered to metal roofing panels – pretty much as a rack-mounting system is part of a Solar PV system using regular crystalline PV panels.
I have always been interested in solar roofing since I live in Tampa Florida. Solar panels are quite common here, but large scale solar roofing is seen very little. I enjoyed reading the roofing article, and found this blog in a Google search.
SIT did not actually file for bankruptcy, despite the fact they had ran out of cash and were losing tremendous amount of money. ECD/Unisolar came to the rescue and bought the company for less than the value of Unisolar inventory on SIT’s books. Had they not done that, the market would have been flooded with cheap inventory, and the truth about Unisolar’s uncompetitiveness would have been exposed much earlier – by “purchasing” SIT, ECD delayed the reckoning by a few months. I am not aware of a fire caused by SIT’s panels, but yes, the SIT solar system at the National Archives and Records Administration (NARA) in Waltham, Massachusetts is dead since August 2009, according to SIT’s own monitoring system ( http://gsanara.rem-systems.com/ ) – what an incredible waste of taxpayer money (the thing apparently cost 13 per Watt: http://www.gsa.gov/graphics/ogp/VSummer2007FINAL.doc )! The situation with “solar metal roofing” on the East Coast, especially on the residential side, must be very similar to that in California. I doubt that all the metal roofing manufacturers combined have done even 200KW of residential installations with Unisolar laminates on the East Coast over the past 19 months. Unless, of course, you have some hard data to disprove my claim. The installation that ASHRAE was referring to is pictured here, after they fixed the sliding “panel,” of course ( http://www.smm.org/sciencehouse/about/ ). Nailing the laminates should probably hold them from sliding, but don’t raise your hopes too high. See what happened on this small roof in Florida after just two years: http://picasaweb.google.com/fan.of.ecd/FloridaInternationalUniversitySolarInDistress
Greetings, I have been wanting to put a solar roof on my house for some time now, but was not sure if doing so in CT was wise because of dreary New England winters. I have been looking at the company linked to in my name – eaglerivet.com, but just found you guys and thought you might be able to offer some insight into a few questions I have. How much does the climate you are in effect the value of the investment in a solar roof? Does it only really make sense for Californians and Floridians? Also, do you know if there is a federal tax credit for going solar or if it is state-based – or both? Lastly, I am a high-tech handy geek of sorts and was thinking about buying the material and putting it up with a group of buddies. Does this seem reasonable to you? Thanks in advance for your advice, Max
Hi Max, I will answer your questions out of order. California / Florida gets about 25-30% more sun light than we do in New England – therefore they generate that much more electricity per dollar invested. Plus I believe they get better solar rebates from the state, though solar dollars run out fast and Cali is on the verge of bankruptcy, so I’m not really sure what their solar rebates are right now. There is a federal tax credit of 30% for solar PV and other approves solar installations. Keep in mind though it is a credit. They apply it to your tax liability. There should be CT state rebates for solar, but they constantly run out of funds, so you should do your reasearch. If your roof is simple with no penetrations, you can certainly do it – install the roof yourself that is. You will need an electrician for the solar part. Apply solar panels on the ground – not on the roof. Clean the panels before applying solar laminates. If your roof goes into moderate to difficult category – hire a roofing contractor in ct – us for example Best of luck.
About SIT (Solar Integrated – correct me if I’m wrong here) From what I understand they went into bankruptcy and were bought out. They were also closely working with Sarnafil / Sika on their PVC solar flat roofing. Problem with SIT / Sarnafil’s solar roofing was more of a panel design than delamination problem. Unisolar custom produced PV modules for them with terminal connectors facing down, instead of up, like their normal Solar panels. This was done to conceal connectors from UV and hide all the wiring under the roof. Problem is that the wiring overheated and I think there was a big-a fire. Apparently, Sarnafil Solar roofing is not allowed to be installed in Massachusetts (their home state) … or maybe its just the government buildings / projects. Most of the info above is UNCONFIRMED. Basically its what I hear when talking to roofing / solar professionals on the inside of commercial roofing market. it is also a mix of information acquired at different times over last few years and I may have made some mistakes / omissions, as this info is rather old, and I begin to slowly forget it. About solar metal roofing – like I said – these installations are on the East Coast – i don’t know the state of affairs in the south, mid-west or west coast. One other thing I need to mention – solar metal roofing by default requires that the ridge cap covers the are of the panel where terminals are, and “z-bar” is crewed to the roof deck through the panel(special area designed for panel penetration), holding down the panels, so i’m not sure how they can slide out. it’s impossible unless they were not installed correctly.
Dear admin: I disagree that solar metal roofs (the ones using Unisolar laminates) are installed left and right (metal roofs with regular PV panels mounted with clamps, like those from S-5!, might be another story). Here is my evidence: The California Solar Initiative ( http://www.californiasolarstatistics.ca.gov/reports/8-04-2010/Dashboard.html ) keeps good data about the installations in that State (and California accounts for about 50% of the solar installations in the US). Take a look at the kilowatts reserved (and not-canceled) for each month since January of 2009 for residential systems (defined as having DC system size of less than 10KW). Here are the total KWs reserved: 200901 2293.9 200902 2368.6 200903 2902.4 200904 4352.2 200905 5875.9 200906 6860.9 200907 4664.4 200908 10218.7 200909 5520.8 200910 7166.8 200911 6084.8 200912 4949.1 201001 4797.9 201002 5192.5 201003 11412.5 201004 13612.9 201005 6437.5 201006 7323.7 201007 7068.6 201008 935.5 Total: 120039.6 kW Here are the reservations with Unisolar laminates: 200901 6 200902 5 200903 0 200904 0 200905 11 200906 5 200907 4 200908 5 200909 9 200910 0 200911 2 200912 5 201001 8 201002 0 201003 3 201004 5 201005 0 201006 0 201007 0 201008 0 Total: 69 kW As you can see, Unisolar’s share in the residential PV market in California is a mindboggling 0.05%! Basically, zero. So, if ATAS, Drexel, Firestone or Unisolar are making claims that they have ANY kind of success with Unisolar laminates in the residential market, they are simply lying. Period. Apparently, the residential customers are less gullible than someone might expect. Yes, the adhesive issue might be more widespread in the membrane solar roofs segment, and it did not end in 2004. Here is what ECD’s 8K/A filing with the SEC related to Unisolar’s acquisition of their largest customer, SIT (specializing in membrane PV roofs), revealed on November 5th, 2009 ( http://investor.shareholder.com/ovonics/secfiling.cfm?filingID=950123-09-57767 ): “Management changed its estimates of the warranty liability [an increase of about 30 million] due to product performance issues discovered which were not fully covered under prior estimates. That information resulted in a significant increase in the warranty expense recorded in the six months ended June 30, 2009. Previously, the warranty estimate was based on historical warranty claims and warranty work performed. The current warranty estimate is based on an evaluation of certain aspects of the Company’s products and systems which indicated that increased failure rates may occur over the typical twenty-year warranty period arising from specialized adhesives used in the SIT manufacturing process and from certain product handling and installation methods. The Company continues to assess its estimate of warranty obligations each reporting period to determine if its accrual is appropriate.” Subsequent to that filing, the warranty liability estimate increased further. So, yes, apparently the adhesive issues are serious and widepsread. Of course, the adhesive issues might be the least of Unisolar’s problems. According to fatspaniel monitoring system, Unisolar’s largest rooftop installation, a 12MW membrane PV roof for GM/Opel in Spain, is dead ( http://siteapp.fatspaniel.net/siteapp/simpleView.jsf?eid=308211 ). And then there was that incident on the rooftop of the Long Beach Convention Center in February of 2008 where the Unisolar laminates (glued to Velcro?) ignited. Finally, Unisolar’s cost of manufacturing for their 6.3%-6.7% efficient laminates was 2.95 per Watt in the March quarter (compare to 13%-14% efficient Chinese crystalline PV panels made at 1.20 per Watt), which results in huge and persistent losses. Things like that. My site is currently closed to readers (but I am considering opening it for public access again).
The solar shingles shown on your picture (SHR-17) were taken off the market and lost their UL certification (the holes might have had something to do with it). I am unaware of any “solar metal shingles” that have have been UL approved and on the market. The “solar metal roofing” with Unisolar laminates has suffered quite a bit of problems due to issues with the adhesive. For example, according to a 2007 ASHRAE report ( http://findarticles.com/p/articles/mi_m5PRC/is_1_113/ai_n25007378/pg_7/?tag=content;col1 ), in “2004 … [the] PV panels [at a high-profile demo installation] slid on the roof, causing a ground fault.” There are reasons why solar shingles and “solar metal roofing” have been losing share in the market since 1998 (their share is currently significantly less than 1%) – cost, PV performance, and reliability.
And yet we see solar metal roofs being installed on residential roofs left and right all along east coast (not sure what’s going on in the rest of the country), and Metal Roofing Manufacturers like ATAS, Drexel, Firestone, etc., are partnering with Energy Conversion Devices or ECD or Uni-Solar, in bringing the solar metal roofing to residential and commercial market. Besides, the 2007 article talks about 2004 adhesive failure. What is the current status or state of the adhesive – has it improved? I know that some flat roofing manufacturers had delaminating problems where panels came loose off the flat roof – namely EPDM rubber membrane, which tend to chalk – and were blown off. Some mod-bit manufacturers like are using their own adhesive to hold the panels down, and are not relying on uni-solar’s butyl adhesive. If these adhesive issues are that serious and widespread (I imagine that this is mostly a problem in hotter southern climates), I do hope Unisolar is working on solving them, as the system design and idea of combining flexible thin film PV panel with a roofing material is great, and it would really suck if they let it slide. Btw ECD fan – what is the point of adding your site if it is by invitation only? I remember I was able to read it before. Why did you close it off?
Installing Solar Panels On A Flat Roof? Here’s What You Need to Know.
To cut to the chase, solar panels work best when they’re installed at an angle facing the sun. However, that doesn’t mean installing solar panels on a flat roof isn’t possible – because it absolutely is.
So, today, I’m going to clear up a lot of things for you so you can also save money on your power bills. Below is a list of the topics and questions I’m covering in this post. I recommend reading from the top but feel free to tap on any of the bullets to jump straight to their sections.
Can you install solar panels on flat roofs?
As I said, yes, you can install solar panels on a flat roof. In fact, flat roofs offer more versatile installations than sloped roofs.
With the right mounting system, your installer can orient your system in angles and orientations that are more optimal to your needs and power output. You also have the option to just have the solar panels installed flat (though I don’t recommend it).
That being said, each installation type also has its own set of pros and cons. Let’s talk about each of them so you know your options.
The best solar panel orientations for flat roofs
Before anything, note that all of the orientations I’m about to highlight need racking systems, so mention this to your installer when you’re in conversation.
Also, we have an article dedicated to the directions solar panels should face in Australia if you want to learn more about that, too. So, without further ado…
Purely east, west, or north-facing solar panels
Like Australian homes with roofs facing north, flat roofs with solar panels tilted north will enjoy a large amount of solar energy. That’s because our land down under is in the southern hemisphere, so the sun moves towards the north.
On the other hand, solar panels tilted to the east enjoy more power during the early morning while west-tilted panels have more energy in the afternoon.
North is the safest option but east or west can be better for you depending on the hours you use the most electricity.
That being said, these single orientations also have their drawbacks. You can’t install them too close because they can cast shadows on each other which limits their efficiency. This, in turn, limits the number of solar panels you can install on your roof.
Mixed (east-west) orientations
Out of all the possible ways to install solar panels on flat roofs, I like this best.
Here, you have one row of solar panels facing east, and right behind it is another row facing west. Repeat as many times as your roof and budget allow.
Shading isn’t so much of an issue here, allowing you to install the most solar panels because rows can be installed right next to each other. And when you have more solar panels, you’re also able to generate more energy.
The caveat is that it’s more expensive and not many installers accept this kind of project. Lucky for you, we can get you quotes from 3 of our pre-vetted installers – for FREE! The more installers you ask, the better your chances of finding someone who can take on this project.
What about solar panels that are installed flat or tilted south? Why not them?
I don’t recommend south-facing panels to Aussies because it faces away from the sun. Meaning, they generate the least amount of energy in total.
On the other hand, yes, you can install solar panels flat on your roof. This way gets you cheap installation costs and a decent amount of energy.
The problem with flat solar panels, however, is that they’re not self-cleaning and are therefore impractical for many.
Rainwater can pool above the panels, so dust and other debris don’t get washed away. Over time, this can decrease the efficiency and prematurely age your system. I can only recommend this in good conscience if you’re willing to regularly clean, dry, and maintain your solar panels.
Is it cheaper and easier to install solar panels for flat roofs?
Installing solar panels on a flat roof and a sloped roof tend to be around the same price, which is about 1000 AUD per kW. Although, this price still depends on your installer and the rack he/she will use.
That being said, flat roof solar panels are typically easier to mount because there’s more space to work around. It’s also safer.
Also, installing solar panels on flat roofs generally won’t require your installer to drill holes either because most of today’s racking systems have enough weight to keep the array stable.
On that note, do tell your installer to use a rack that can withstand heavy winds so your solar panels don’t get blown away.
Key takeaways: Pros and cons of solar panels on flat roofs
Pros:
- Flat roof systems offer more versatility when it comes to orientations (directions and angles).
- Flat roof solar panels are cheaper to install; angled solar panels are more efficient and self-cleaning.
- Installation costs for a flat solar panel system are about the same as sloped roofs. Sometimes higher.
- Flat roofs are easier and safer for your installer.
- Weighted racking systems mean no holes will be drilled on your roof.
Cons:
- Installers who accept jobs on flat roofs are harder to find.
- Flat roof solar panels will require more cleaning.
- Flat roof solar panels will have water pooling on top of it, possibly leading to damage.
- Wind damage is a possibility with panels that are installed on unfitting racks.
Conclusion
To recap, yes, you can install solar panels on your flat roof but it will be a slightly different process.
For one, you will have to figure out what orientation best fits your lifestyle and one that maximizes your roof space and budget. Your roof also has to be strong enough to handle the weight of the racking system as well as the entire array.
I hope this helped! And, remember, if you’re having trouble finding an installer for your flat roof, we have a network of installers that we trust. You can trust them, too.
Solar Installation on a Flat Roof
Using solar energy to power your home or business is a Smart decision. As you save money on your electricity bills, you protect the environment. If you have a flat roof, it should not prevent you from enjoying these benefits. You can gain as much value from solar on the flat roof by using the available surface.
According to consumer reports, flat roofs can make some of the best space for solar panel installation. Let’s look at all the information you need to know when installing solar panels on a flat roof.
How Do Solar Panels Work on a Flat Roof?
You mostly find flat roofs on commercial buildings. However, residential areas also use this option. The solar panels installed are the same as the traditional PVs, but there are various considerations to make. Such include:
- The solar panel system’s ability to clean itself when it rains: The collection of water around the solar panels can damage the system. It can also affect your roof.
- It should also be sturdy enough to avoid damage from strong winds. Strong winds present a potential risk to your solar energy system.
- You should also consider the system’s pitch, ensuring it captures enough light. The more sunlight it captures, the more energy you generate.
- You may require experts for this roof type. Not all installers are skilled to offer flat roof solar installation.
Advantages of Flat Roof Solar Panel Installation
There various considerations when installing solar panels on a flat roof. But there are many benefits of installing panels on the flat roof. These are:
Easy to Access
It is easy to access a flat roof, and it reduces the chances of a fall. For this reason, it is easy to install the solar panels as the movement for installers is easier. The maintenance is also easy as you do not need special equipment to access the roof.
Doesn’t Affect a House’s Aesthetic Appeal
When you purchase a home, there may be guidelines from the homeowner’s association about its appearance. Also, you may have a specific design that you want to maintain. Often, the panels are rarely seen from the street when installed on a flat foot. As a result, your neighbors will not complain about your solar panels being an eyesore.
Tilting Your System for Maximum Sunlight
When an installer is designing a solar system for installation, they take the roof’s angle into account. Ideally, roof panels should face south at an angle equal to the latitude of the location. Also, some sloped rooftops tend to be steeper, producing less electricity as a result. Such factors can lead to a reduction in power generation over the years.
If you have a flat roof, you can avoid such variables as they offer flexibility. When installing the panels, you are free to orient them to face south. Additionally, you can angle the system regardless of the direction your roof faces. As a result, you can maximize your energy production.
Protect Your Roof
Often, a sloped roof requires drilling when installing the solar panels to keep them securely in place. These penetration mounts leave holes in your roof. The more panels you install, the more holes you will drill. Flat roofs require weighted structures to secure the solar panels eliminating the need for perforations on the rooftop. A ballast system utilizes gravity weighing down the solar panels.
Challenges of a Flat Roof Solar Installation
As much as there are advantages to installing solar panels on your flat roof, there are some challenges too. However, you can solve them to get the best solar energy system.
First, the installation company may recommend that you use special equipment to maximize energy production. Tilted mounts are some of the structures you may need to do so. The mounts tilt your solar panels, exposing them to more sunlight. As a result, the total cost to install the solar panels can be slightly higher than the slanted roofs.
You can use the ballast system to mount the panels. The roof can fail to handle the weight of the ballast. Additionally, if you add the drilling method, it may lead to roof leakage. The good thing is that technology has advanced enough to prevent such an issue from recurring.
Take Away
Installing solar panels on your flat roof is not impossible. Yes, there are challenges that you and the installer may face, but you can overcome them. First, you should ensure the solar panels can properly drain when it rains. Second, yous should firmly secure the PV modules to protect the system from strong winds.
Lastly, the panels should have a good pitch where they can capture enough sunlight. As they capture more light, they can generate more electricity to meet your needs. Remember, always use a qualified installer.
Dynamic Slr is your go-to solar installation company in Texas. Do you want to install solar panels on your flat-roof, ground, pole, or carport on residential or commercial premises? Fill in the free solar quote and start the journey to an environmental-friendly energy source.
Solar Panels On A Flat Roof? Consider East-West Tilts
To maximise the solar energy generated over a year, the perfect roof to install solar panels on in Australia is large, north-facing and inclined at an angle close to the location’s latitude.
Panels mounted parallel to this perfect roof will be optimised for annual energy yield, and in most parts of Australia, should seldom need cleaning. Thanks to their angle, rain will slide off, cleaning as it goes.
Flat roofs are not ideal for solar.
If you mount the panels flat, the biggest problem is not reduced energy yield compared to north-facing panels. The biggest problem is rain pooling on those flat solar panels. They won’t self-clean in the rain, and grime will build up over time. This will compromise your energy yield and potentially slowly eat the seal between the aluminium frame and the glass.
The Clean Energy Council Installation Guidelines state:
“A minimum tilt of 10° is recommended to take advantage of self-cleaning during rain events. Where panels are installed at a tilt angle less than 10°, the customer shall be advised about the need for more frequent cleaning of the modules, and this should be included in the recommended maintenance schedule.”
Some people are happy to live with flat panels and either accept the reduced energy from grime build-up or clean them regularly.
But if you don’t want flat panels on a flat roof, the obvious option is to install them on tilt frames. And the traditional thinking on a residential roof is: if you are going to the effort and expense of tilt frames, you may as well tilt the solar panels to the north and at the optimum angle for the location – approximately the latitude.
This logic makes sense in the bygone era of expensive solar panels. You wanted to squeeze as much energy as possible from each panel.
But now solar panels are so cheap, the homeowner’s priority is more often squeezing as much energy as possible from the roof area. That can often lead to a different system design than the traditional approach of maximising yield from each module.
Getting the most energy from a flat roof.
To get the most energy from a flat roof, you need to maximise:
The optimum design will depend on many factors unique to your property; including roof shape, shade objects, location in Australia, wind rating and roofing material. But to help you consider your options, I’m going to use an example of a 9m x 6m flat tin roof in Adelaide with no external shading. We will be using 60 cell, 380 W solar panels (1.048m x 1.748m).
Option #1 : 21 flat panels 7.98 kW
Annual energy yield per roof: 10,998 kWh (assuming regular cleaning).
Annual energy yield per panel: 524 kWh
- Panels won’t self-clean in the rain
- Some solar panels are not warranted for flat installation
- Energy yield per module is lower than north-facing
In our example, we can comfortably fit 21 x 380W solar panels, laying them flat.
Option #2 : 15 panels (5.7 kW) tilted north at 30º
Annual energy yield per roof: 8,487 kWh
Annual energy yield per panel: 566 kWh
- most energy per solar panel
- lots of roof access
- will run a little cooler
- will self-clean in rain
- can only fit 15 panels to avoid excess shadowing between rows
- rows will still cast some shade on each other at the end of the day – especially in winter
- 30º tilt frames are fiddly to install and add to installation and racking cost per module
- Not a great design for strong winds
Option #3 : 24 panels (9.12 kW) tilted east-west at 10º
Annual energy yield per roof: 12,592 kWh
Annual energy yield per panel: 525 kWh
- can fit the most solar panels (on this particular roof)
- self-cleaning in rain
- intra-row shading is negligible
- a little more energy in mornings and evenings
- takes longer to install than flat – but not by much due to innovative racking design – e.g. Clenergy’s ComT racking
- expensive than flat (100 – 150 per kW more)
- Not all installers will offer it
For this roof, east-west tilt wins
East-west facing solar panels, in this example:
- generate the most energy overall
- generate the same kWh per panel per year as flat
- remove the need to clean flat solar panels regularly
- remove the problem of pooled water eating the module seals over decades
- give (a little) more energy at the beginning and end of the day
- and, if you ask me, looks killer!
Of course, the relative number of panels that can fit with each design will change depending on the shape, orientation and screw-lines of your roof. A good installer will work out the optimum layout for your roof based on whether:
With the inevitability of homes and cars becoming all-electric, I’d recommend the latter.
The best racking for east-west tilts on a flat roof
If you want east-west tilts on a flat roof – the racking of choice is currently Clenergy ComT.
The most innovative components in this racking system are the top and bottom legs that mount the solar panels at a fixed 10º:
And here’s a video showing the entire installation process:
Clenergy ComT is sold as commercial racking but works great on residential roofs.
Here are the boys from Solar Wholesalers 2 in Adelaide installing East/West Clenergy ComT on a residential roof.
If you have a flat roof – ask your installer about east-west tilts. You’ll potentially get more energy, longer solar panel life and be up for a lot less cleaning.
Footnotes
- Some solar power fans may call that a disadvantage. ↩
- Hat tip to Solar Wholesalers for alerting me to this concept originally. ↩