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In my previous article I discussed the mounting points for a roof-mounted solar electric system. There is another equally important consideration: the roof underneath your solar panels. This is crucial to think about when deciding to buy a solar electric system. Since solar electric systems are expected to last for 25 years and up, you need to consider the condition of your roof. It’s a lot easier and less expensive to do any necessary roof work before you install a solar electric system. If you have a new 50 year composite shingle roof then you should have minimal concerns (make sure the installation is flashed correctly – see my previous article ), but if you have a 30+ year old composite shingle roof then you should consider a new roof prior to installing solar electricity. Of course many of you will be in a situation where it is not so “black-and-white”. This is where a good solar installer can help you. After working on roofs for years, a good solar contractor you can tell quite a bit about the condition of the roof and can give you good recommendations on what to do for your specific situation.
Composite (or “comp” shingle) roofs typically have the shortest lifespans, but you can buy very high quality 50 year shingles. These 50 year shingles are thicker and typically cost more, but make great roofs that last a very long time. Here in Southern California concrete tile roofs (both flat tiles and S-Tiles or Spanish Style) are very common and last an extremely long time. In fact, the concrete tiles usually toughen up over time from baking in the sun year after year. If nothing breaks these tiles then they should not wear out in a VERY long time, but the waterproofing material underneath does sometimes. If you have a concrete tile roof and have had leaks in the past it’s probably a good idea to “reset” the tiles and put in a new waterproofing barrier underneath them (resetting roof tiles just means pulling them up, putting down a new waterproofing layer, and then putting them all back in place and replacing any broken tiles). You may also want to consider resetting your roof tiles if you have an older tile roof. The tradeoff is the added cost of resetting the roof versus the risk of leaks in the future. Also, make sure your solar contractor will replace any broken tiles they find. This is very easy to do and should not be a big deal.
Clay tile roofs look great but are typically a bit more delicate and usually cannot be walked on without breaking tiles. This creates some different considerations and will require more work to install solar so the installation costs are higher. The same is true for “lightweight concrete tiles”.
Flat roofs seem to be more prone to leaks, so inclined or pitched roofs are usually better locations for solar. Solar can of course can be installed on flat roofs to minimize the chance of leaks, but it is more difficult because water often pools and stands on flat roofs until it evaporates. This gives the water a lot of time to “find” a way in. This does not happen with pitched roofs because the water quickly runs off.
If you’re not sure what kind of roof you have or it’s condition then ask your solar contractor. They can take a quick look at your roof and tell you quite a bit.
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
 Flashing for Solar Electric Mounting Points The connections of a solar array to your roof are crucial for a successful long-term, trouble-free solar electricity installation.
These connection points to your home/roof need to be flashed and waterproofed properly using standard roofing practices. These will look very similar to the other flashings around your existing roof vents. If they are not flashed correctly then water can get through the roof of your home that can cause many types of water damage and eventually structural damage to your house. Water damage is expensive to repair. This is why roofers use this “flashed” method. It is time tested and proven in real-life.
If any installer just wants to drill a hole and patch it up with caulking or use any other “non-flashed” method, I recommend finding another installer. I have not seen any method besides flashing that will hold up for many years leak-free. And remember these solar electric systems are expected to last 25-50 years. Make sure any installation includes proper flashing!
The solar array must also be securely anchored to your roof. If the anchor points are weak the array could be blown off the roof in a storm and who knows where it will land. On your car, a neighbors car, a neighbors house, or ??? Also, if the array moves or “wiggles” in a storm it could damage electrical connections or weaken waterproofing of the panels themselves. This could also be an expensive repair and a safety concern. Fortunately, there are excellent manufacturers that make high quality solar array anchors that work great.
As always make sure your solar electric installation is done correctly at the beginning and you should expect many years of trouble-free free electricity from the sun!
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
I get quite a few questions about and see a lot of articles on “thin film” for solar electricity. And many of these articles seems to cause more confusion than help explain what “thin film” solar actually is and is not.
Thin film is just a thin layer of semiconductor material deposited onto a base material which can be a flexible plastic or metallic sheet. The major advantage of “thin film” is it is much less expensive to produce. It can also be made to be flexible. The major disadvantage of “thin film” is that it is much less efficient. What this means is that “thin film” will take up much more space to produce the same amount of electricity as typical crystalline silicon panels would. Typically, it will take almost double the space to produce the same amount of electricity.
Thin film solar is not based on slowly growing large silicon crystals. This is important because large silicon crystals are expensive to produce and so drive up the cost of solar electric cells and panels. This is the primary reason why “thin film” is so much less expensive to produce.
Today crystalline silicon solar panels are much more common for residential solar electric systems. This is primarily because thin film based solar panels will take up much more space than the “normal” crystalline silicon panels would. Many people who live in cities or the suburbs do not have a lot of extra roof space to waste. In fact, most people do not have enough roof space to produce as much electricity as they would like, so efficiency and the amount of roof space can be crucial. In many cases, thin film may not be good solution because it simply needs more space than is available. However, in situations when you have plenty of space (like in a field) it can be an extremely cost effective solar energy solution (as long as the savings for the panels is greater than the cost for extra racking/mounting for the larger area required). There are also concerns about the toxicity of some of the chemicals used in “thin film” panels and what the long-term effects may be, but is no definitive answer to these concerns yet. For now, thin film is used almost exclusively for large scale commercial solar with a few exceptions (typically leased).
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
On a regular basis I hear or read there is a new solar “whatcha-ma-gadget” (or fill in the blank). It is typically some new, fantastic, incredible, unbelievable, “wizbang” technology. It’s never available right now, but will be “sometime soon”. Unfortunately, I have not yet seen one of these materialize. It has always turned out to be over 20 years away, urban legend, impractical, impossible, or just not applicable. But I’m still hoping for one of these to actually come through. Someday . . .
With solar power there are constant small improvements over time, so I would expect solar electric systems to be better in 5 years and even better in 10 years. So if you wait you will get a better system. Right??? Well yes, but . . . That is sort of like waiting for the next latest and greatest computer or television or cell phone before you buy one. The problem with this approach is that you will never own a computer or new TV or cell phone, because there are never-ending improvements. You know that soon after you buy one there will be some newer, faster, cheaper, better feature on the newer model that would be nice to have. But you don’t necessarily need it. More importantly, if you wait for that unknown feature you lose out because you don’t get the benefit of a computer or TV or cell phone while you’re waiting. I doubt that you are still be waiting to buy a cell phone or computer today.
Solar technology is similar because there are also constant improvements. This does not seem to be anywhere near as rapid as the changes in consumer electronics, but there is still constant improvement. And now with all the attention on solar electric, I expect this to accelerate. These never-ending enhancements should improve the cost, reliability, and efficiency of solar electricity over time. But these will for the most part be small, incremental, ongoing changes. Revolutionary jumps are not very likely.
So yes, if you wait you will probably get a better system for a better price. However, you will not get the benefits of all the solar electricity and the savings on your electric bill while you are waiting. How much will you spend on your electric bill month-after-month and year-after-year while waiting for a better solar electricity system? Or you would you rather do your research and get the best system available today that is in your budget and start saving money on your electric bill right away?
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
Have you ever thought of a solar PhotoVoltaic (PV) system as an investment? Looking at it this way is an excellent way to analyze whether it is worth buying a solar electric system or not.
Start with considering the amount of money spent on a system, which includes the purchase price (or down payment and loan payments over time) and small ongoing maintenance costs. Then consider the amount of money saved on your electric bill over the months and years.
If you do a financial analysis on these “cash flows” over time you can decide if Solar Electricity is a good choice for you. Very often you can achieve a “Rate of Return” or “Yield” of 10-20% and often even more with financial leverage from a loan. What else can give you this kind of return?
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
For the most part it is because no one has explained how it works and what all of the advantages are. State rebates, federal tax credits, net metering agreements all make solar electricity very attractive. Additionally, solar panel prices have dropped significantly, which makes them much more affordable and easier to make a financial case to install them. Yes, there is an up front cost, but the monthly savings can more than make up for the initial investment. There are some cases where people just do not use enough electricity, but many people would benefit overall from using a solar photovoltaic system. The only way to know is to look at the numbers and do the analysis.
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
1) Save Money – Even if you have a $200, $300, $400, $500, $600 per month electric bill you could bring that down to only $5.17 per month! Imagine having only $5.17 per month electric bill. And make the government pay for nearly half of the total installation while at the same time increasing your property value.
2) Help the Environment – Lot’s of people are talking about being green, but you could actually do it with a solar photovoltaic system. Making the world a better place to live today and for our children’s future. Wouldn’t you like this to be part of your “legacy”?
3) Energy Independence – Reduce dependence on other sources of energy, like nuclear, foreign oil, dirty coal
4) Pride of ownership – Be the talk of your neighborhood. Be proud that you are making a difference and saving money. Wouldn’t you like to show your electric meter running backwards to your family and friends.
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
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You’ve probably asking yourself: Sure, this “Solar Electricity” sounds great but how does it actually lower my electric bill? Instead of buying 100% of your electricity from SDG&E, your solar electric panels produce part or all of your electricity, just as you would expect. In the end, you end up buying less electricity and so have a lower bill.
However, many people are gone during the day when their solar panels are producing the most. Instead of wasting this solar electricity, it is “pushed” back out to the electric power grid and the utility company buys electricity from you. It can actually make your electric meter run backwards.
It’s beautiful in its simplicity. Your electric meter does only one thing. That is, measure how much electricity flows through it so the utility knows how much to bill you. When you produce more electricity than you use and “push” electricity back to the grid, SDG&E is effectively buying electricity from you.
Staying connected to the electric grid is important because the utility company will provide electricity when the sun is not out. It’s almost like you are “storing” energy on the utility grid for future use. The utility company buys electricity from you during the day and you buy it back anytime you need it.
This is done through what the utility company calls, “Net Metering”. Your electric meter measures how much electricity flows through it so the utility can bill you for the amount used. Now what do you think would happen if you could “push” electricity back to the utility company. You have probably guessed that the electric meter would run backwards. That’s what Net Metering is and that is what a solar electric system does when you produce more electricity than you are using.
This is important because Photovoltaic systems produce electricity only when the sun shines on them and they produce the most in the middle of the day. This is a time when many people are not home and are not using much electricity. So your electric meter runs backwards in this case, and allows you to effectively “store” electricity with your utility company for use when you are home. The utility company buys electricity from you during the day and you buy it back when you need it.
The amount of electricity is “netted” out every year starting on the first day your system is connected. In other words, the amount of electricity “generated” over one year is subtracted from the amount “used” over one year and you pay only for the “net” or remaining amount for that year.
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
 It could be, BUT !!!!!!!!!! I don’t recommend it unless you have a LOT of experience with electricity and working on roofs.
This is one of those times that for most people it’s probably best to hire a professional that specializes in Solar Photovoltaic Systems (PV). I strongly recommend finding someone who focuses exclusively on solar photovoltaic (PV) systems. I don’t recommend hiring a general contractor or general electrician who also happens to do solar installations, unless that is the main part of their business. At least, if you want it done right. Find a specialist!
Safety and reliability are extremely important when installing a Solar electricity generating system. If it’s done wrong you can hurt or kill someone, start a fire, create leaks in your roof, and the list goes on-and-on. Or you might just get a system that performs poorly.
If your system is installed correctly you should expect to get many, many years of hassle-free and safe electricity from the Sun! To get a system that operates properly and efficiently, the following (at a minimum) must be included and understood in your preliminary analysis: Solar panel ratings and specifications, Inverter ratings and specifications, your home’s power distribution panel and busbars’ ratings and specifications, Panel orientation, shading, the sun’s path and useful daylight throughout the year, wire sizing, temperature derating factors for panels/wires/junction boxes/etc, and the interconnect to the utility power grid.
Here is a list of a some of the most important things to remember if you’re considering Doing-It-Yourself:
- Do you have the knowledge and experience comparable to a trained and experienced electrician? And roofer for rooftop installations?
- Do you understand the details of how to optimize your solar panels outputs based on your current electrical usage and the Sun’s path throughout the year
- Do you know how to protect yourself from falls, high voltage, and high current equipment?
- Do you understand the National Electric Code (NEC) and common practices of local permitting authority (usually city or county)? This is a difficult read to say the least.
- You will need to get building permits and have safety inspections before turning on system. And remember you have to work with both the utility company and the local permitting authority.
 Do you understand why Ground Fault Protection Devices, Circuit Breakers, and cutoff switches are installed and how they operate?- Do you understand wire sizing and how to run wires safely?
- You need to understand a multitude of safety precautions when working with DC and AC electricity. This includes working on a rooftop and all the way to the circuit breaker box (power distribution panel).
- Remember solar arrays often product voltages up to 600 volts and currents of 20 to 30 amps for residential systems and can be considerably higher for larger or commercial systems. These are dangerous voltage and current levels if you are not experienced with electricity!
Remember safety first! This is for yourself, for others, and for your home.
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
 In my last entry, I discussed how the Sun affects your life every day and how you can harness a bit of that energy to reduce your monthly electric bill. The basic idea is that a solar electric system captures the sun’s energy and converts it into electricity that you can use in your home.
By now you’re probably asking yourself, “Sure, this sounds great but how does it actually lower my electric bill?” Instead of buying 100% of your electricity from SDG&E, your solar electric panels produce part or all of your electricity, just as you would expect. In the end, you end up buying less electricity and so have a lower bill.
However, many people are gone during the day when their solar panels are producing the most. Instead of wasting this solar electricity, it is “pushed” back out to the electric power grid and the utility company buys electricity from you. It can actually make your electric meter run backwards.
It’s beautiful in its simplicity. Your electric meter does only one thing. That is, measure how much electricity flows through it so the utility knows how much to bill you. When you produce more electricity than you use and “push” electricity back to the grid, SDG&E is effectively buying electricity from you.
Staying connected to the electric grid is important because the utility company will provide electricity when the sun is not out. It’s almost like you are “storing” energy on the utility grid for future use. The utility company buys electricity from you during the day and you buy it back anytime you need it.
Now, if free energy falling from the sky isn’t enough to make you think about solar; it gets even better. There are state rebates to help you pay for installing a solar power system. These rebates are based on the system size and how much electricity it should produce. Right now it often works out to be about 3 to 5% of the entire cost of the system.
“But wait, there’s more”. No, it’s not a “Shamwow” or set of “Ginsu Knives” or whatever is on your favorite infomercial. There is a 30% Federal tax credit.
When you add together these two “incentives” they typically pay for about 1/3 of the entire cost of the system.
To make it even better, a solar electricity system adds value to your home. If you ever want to sell your home, the solar system on the roof will increase the property value and make your home more attractive to potential buyers. It makes a “For Sale” home stand out from the crowd. It’s a great selling point. How would you feel about buying a home that makes its own clean electricity from the sun?
Your property value increase may actually be higher than what the entire solar system cost to install. Increased home value estimates for a home with a solar photovoltaic system are often estimated between 20 times the annual savings on electric bills to $20,000 per kilowatt installed with most homes having at least several kilowatts. This can be a very substantial increase in home value!
Robert Morse
BSEE, MSEE, NABCEP Certified PV Solar Installer
CA State Licensed Electrical Contractor (C10) & Solar Contractor (C46)
SunCal Solar, Incorporated
Have a Question? Contact Us at: blog@SunCalSolar.com
It’s free for anyone to subscribe by clicking on the “Posts” or “By Email” (RSS Feed or Email) subscribe buttons at the upper right corner of this website.
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