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DIY Home Solar: Planning a Solar Array (Beginner's Guide)

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Picture of DIY Home Solar: Planning a Solar Array (Beginner's Guide)
Hi there!

Maybe you've considered solar energy - even if only for a brief moment - only to dismiss it as too complicated and too expensive, or maybe you're seriously considering a project, but don't know where to start. With this Instructable, I hope to demystify the (not-really) intimidating process of installing solar panels in your home. We'll review the parts of a solar panel system, the things you need to consider when you're planning, and how you can save money on (and even get free money for) your project. At the end of the day, you'll know what to look for and what to keep in mind with any solar project.

Why Go Solar?

If you've been thinking about going solar, there's no better time than now to do it. Government financial incentives are still ripe for the picking, the cost of photovoltaic (PV) cells is falling every day, and you'll probably be the first person on your block to make the jump. Adding solar energy to your house is an excellent project for several reasons: You'll save loads on electricity, and may even be able to sell some of yours back to the utility company; you'll reduce your carbon footprint; and if you're installing in a remote location (such as a cabin), you'll have much less to worry about than you would with a gasoline generator. You'll also support a growing industry, and in doing so, help contribute to the worldwide adoption of this wonderful new energy source.

Further Reading:
Throughout the guide, I'll be providing links to articles from SolarTown.com's learning center. This guide is meant to be very broad, so that you know what to keep in mind and what to plan for. Once you start researching individual products, though, you'll probably want a little more specific information. Hopefully, these links will address your questions. If anything you need to know isn't covered, feel free to surf over to our community page and ask an expert solar installer.
 
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Step 1: Parts of a Home Solar Energy System

Picture of Parts of a Home Solar Energy System
The hardest part of starting a project like this is knowing what to buy, so we'll look at a list of parts before we get into the nitty-gritty.

What's Grid-Tie?

This article is going to assume that you'll be building a grid-tie (or "on the grid") system. Grid-tie means that your house will still be connected to the utility company. The biggest benefit of staying on the grid is net metering: If you're producing excess power, you can actually sell it back to the utility company. Since your system will help produce green power for the grid, and reduce the overall strain on the utility company, they'll buy it from you at a huge premium. Because you're still on the grid, you'll still have power on cloudy days.

What do I need?

These are the parts of a grid-tie system, in order:
1. Solar Modules (aka PV Panels) collect energy from the sun and turn it into direct current.
2. Power Inverter turns the DC from the panels into AC that your appliances can use.
3. PV Disconnect lets you cut off power so that you can work on the system without electrocuting yourself.
4. Your home's breaker box is where the solar energy connects to your house.
5. Net meter connects your house to the grid, measuring how much power you take from - or give to - the power grid at large.

You can buy panels, racking, inverters, and more at SolarTown. As we continue through this article, we'll look at some of the products that are available and what each will cost. If you feel overwhelmed by all of the different options, we sell packages that include panels, racking, and the inverter at discount prices, so give that a look as well! You could have a 5kW system for $35,000. Try not to let the price tag turn you off - we'll look at government programs to help cover the costs in step 7.

Now that you're familiar with the vocabulary, we can get to planning your solar array.

Step 2: Load Calculation

Picture of Load Calculation
Knowing how much power you need is the first step to planning your array. Since solar panels are measured by how much energy they can absorb, this will tell you how many panels to buy, how efficient they need to be, and (perhaps most importantly) how much space you're going to require. Don't worry, this process doesn't require more than your utility bills and some basic math.

First, check out your utility bills to see how much energy you usually consume. Typically, this number falls around 900 kWh each month, but it varies wildly from household to household.

Next, find out the "peak sun hours" of your area. This number is a measurement of how sunny someplace is. On the West coast, this number is between six and seven hours; on the East coast, between four and five. The National Renewable Energy Laboratory has an excellent insolation map. Follow the link for Photovoltaics under U.S. Solar Resource Map.

All that's left now is to do the math. At 900 kWh each month, you're burning 30 kWh each day. Divide this number by the daily peak sun hours. If I use 30 kWh in a day, and there's five hours of sunlight, then I need 6 kW worth of panels to match all of my usage.

Step 3: Choosing Panels

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There are two basic kinds of panels: Crystalline and thin-film. Choosing one or the other has major consequences for the rest of the installation process, so we'll look at the differences between the two before we make any decisions about how to mount them.

Crystalline

Crystalline modules are the big blue panels that usually come to mind when you think about solar power. They're very efficient and very durable. A 40 year lifespan is more than you can ask of many home improvement projects, and gives you more than enough time to make your money back in savings. A drawback of crystalline is installation. These cells require a somewhat elaborate racking system. We'll cover racking on the next page.

For a 6kW system (fully power an average household), crystalline panels would cost about $16,500: You would need 25 panels supplying 240W each. 240W panels cost $660.

Thin-Film

Thin-film comes on a roll of flexible material. Though crystalline modules are more popular, thin-film is gaining a strong foothold in the market due to its ease of use. The two biggest advantages of thin-film are cost and convenience, since installation is as simple as slapping the module onto a smooth surface. One major drawback of thin-film, however, is durability - Thin-film usually only lasts around 25 years. Compared to crystalline, thin-film is usually more efficient in the dark, but less efficient in general.

For a 6kW system using thin-film, you would need 44 panels supplying 136W each. The panels cost $472, so the total would be $20,768. Although the thin-film panels are slightly more expensive, you don't have to buy expensive racking for them.

Keep the differences between these two modules in mind as we discuss location considerations on the next page.

Further Reading:
Buy solar modules at SolarTown.com
Consumer Guide to Buying Solar Panels
Comparison of Several Leading Solar Panels
Comparison of Thin-Film and Crystalline Panels
Blog: Aesthetics of Solar Panels

Step 4: Solar Panel Racking and Location Considerations

Picture of Solar Panel Racking and Location Considerations
If you go with crystalline modules, solar module racking (the bits and pieces that hold your panels in place) may be the most important part of your project. Here, we'll discuss a few things to keep in mind while you determine where you want your solar panels to go. If there's too many obstacles to crystalline panels, you'll definitely want to consider thin-film instead.

Roof Mounting

Roof mounts are especially great since they're aesthetically pleasing and don't take up any space in your actual yard. There's a lot to consider with roof mounts, however. Most importantly, you'll need to think about the actual strength of your roof. If you live in an older house, you might have to get your roof redone before you can start bolting PV panels to it. Thirty panels weighs an awful lot, and it'd be a shame to have the whole thing come crashing down into your living room. Besides the strength of your roof, you'll need to make some decisions as to whether it's the most effective location.

Your goal is to expose the solar panel to as much sunlight as possible. First and foremost, this means you need to avoid shade - one panel in the shade can affect the efficiency of the entire system. Be sure to keep details in mind: Will the neighbor's big oak tree grow in the next ten years? Will something that's out of the way at this very second be casting a shadow later in the day? You also need to consider the qualities of your roof. In order to get the most direct sunlight, your panels should point towards the equator (South, in the Northern hemisphere) - will your roof accommodate this? And is the roof big enough to hold your panels? Another, more obscure consideration is your homeowner's association. Some people think solar panels are an eyesore (personally, I think they make your house look great) and may have banned them in your neighborhood.

If it looks like a roof mount isn't the best idea, you have nothing to worry about. If you're concerned that your roof isn't stable enough for thirty crystalline panels, you may want to consider thin-film. If your roof has too much shade, you can still rack the panels in your yard.

Ground Installation

Ground installation is very easy, since you don't need to spend the day mucking about on your roof. Ask yourself if you have the land to sacrifice for the panels, and again, pay attention to details when you're picking the site. Two not-so-obvious considerations are soil and wind - You don't want your big, expensive solar array to be sucked into a sinkhole, and you don't want it to blow away like a giant sail. One of the big advantages of a ground install is that you can have the panel on a pivoting pole, so that it follows the sun. These movable mounts are expensive, but they'll significantly increase the output of your system.

Now that you know what panels you want and where to put them, things get pretty easy from here on out.

Further Reading:
Homeowners Associations and Solar Panels: Can They Live in Harmony?

Step 5: Solar Inverters

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Picking an inverter for your system is pretty important. Fortunately, there's not too much room for error. You need to make sure that you're buying a grid-tie inverter, rather than off-grid. You'll also need to check the wattage rating to make sure it can handle your solar array. Finally, you can consider buying micro inverters. Remember how I said that a single panel in the shade can affect the efficiency of your entire system? A micro inverter system uses a small inverter for each panel, instead of one inverter for all of the panels. The shoddy performance of one panel won't be able to affect the rest of the system.

For our hypothetical 6kW array, we could use a 6kW SunnyBoy inverter - $3,999.00 at SolarTown.

Now that you've picked panels and inverters, the hardest parts of the planning phase are over. Whew!

Further Reading:
The Good, Bad, and Ugly in Inverters: All the Questions You Need to Ask

Step 6: The Net Meter and Battery Backups

Picture of The Net Meter and Battery Backups
Net Metering

As you know, your power meter measures the amount of electricity you take from the grid. It is very likely, however, that you'll need to get a special meter that is able to spin backwards - without it, you can't accurately measure the amount of energy you're giving back to the grid. In most cases, you can call your utility company and they will provide one of these meters for free. As I said before, having a power station in the middle of the grid - even a tiny one - takes a lot of load off of the system, and the utility company will gladly assist you with your solar home.

Battery Backups

Although solar battery backups are outside of the scope of this article, I find it necessary to at least mention them and why they are useful. First, battery backups are good in the event of a blackout. Unfortunately, your solar panels will not power your home if the lights shut off. This is to prevent your system from frying a lineman who's repairing the grid. A battery blackout will let you keep your refrigerator running while the power's out. Second, if you are running an off-grid system, you'll need the batteries when the sun's not shining.

Step 7: Finances, Installation, and Some Final Phone Calls

Picture of Finances, Installation, and Some Final Phone Calls
Finances

As you may be aware, the Federal government will provide you with a hefty grant to reward you for being a part of the transition to renewable energy. Just how hefty, you ask? The incentive program will cover 30% of your costs. Not bad, right? For more free money, be sure to check out North Carolina State University's DSIRE. Many states, towns, and utility companies provide additional grants, tax breaks, buyback programs, and low-interest loans to help offset the costs of solar energy. DSIRE maintains an up-to-date list of these programs.

Installation and Regulation

Before you begin, you'll need to make sure that what you're doing is legal. Call your local government and find out what kind of building permit you need - often, for renewable energy, they will waive the permit fee. Also be sure to contact an electrician. Even if you are installing the entire system yourself, you'll need to have it inspected, just to be safe. An electrician can help with problems or opportunities you may have missed. Be sure to read DSIRE carefully - It has some information on state and local regulations.

Another thing to double-check on DSIRE is the installation requirement for any incentive programs you may apply for. Although I'm sure that the most Instructables users will opt for a DIY solar installation, you may not be qualified for state or local grants if you don't hire a government-approved contractor to do it for you. That said, a do-it-yourself solar project is both fun and rewarding! Check out the further reading for some advice on DIY solar.

Further Reading:
Going Solar: What Are the Economic Incentives?
Solar Installation Challenges: My First Person Report
What You Need to Know When Selecting a Solar PV Installer

Step 8: Conclusion

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We hope you've found this guide to be helpful and informative. Home solar energy isn't terribly complicated, and with government incentives, it isn't terribly expensive either. In the long run, you can save a lot of money on your energy bills, and even make money by selling power back to the utility company. Once you know the parts of a solar array, the entire process is much less intimidating - it's just a matter of adapting the formula to your specific situation. Stop by SolarTown.com for more learning articles, solar news stories, affordable solar modules and components, or if you have any questions for a solar expert. Thanks a lot for reading, and have fun with your solar project!

For the next part of our DIY home solar installation, visit the second piece on Instructables called (how to select the right solar rack)

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Image Credits
All images shared under Creative Commons licenses.

I. Gray Watson http://256.com/solar/ cc by-sa
1. Oregon DOT http://www.flickr.com/photos/oregondot/3077175469/in/photostream/ cc by
2. Brendan Wood http://www.flickr.com/photos/brendanwood/2161236298/ cc by-sa
3. Clearly Ambiguous http://www.fotopedia.com/items/flickr-45978012 cc by
4. Lauren Manning http://www.flickr.com/photos/laurenmanning/2205351010/ cc by
5. reedyoung http://picasaweb.google.com/lh/photo/5Kzzsf3A5pmYO88bXB7ALQ cc by-sa
6. MRBECK http://www.flickr.com/photos/mrbeck/2718357659/ cc by-nd
7. edinburghcityofprint http://www.flickr.com/photos/30239838@N04/4271445364/sizes/m/ cc by
AaronJ73 days ago

Any tips on wiring the solar array to the house wiring?

RathishT22 days ago
Dennis Gray1 month ago
praetorian2163 months ago

Thank you. Been looking for something like this.

really good information about solar home. here i have got a site which is about green living and wise living.

arifbinali8 months ago

Nice guidelines on planning a Solar Array. As a beginner I am happy to get these information. Previously I read solar home guide blog.

lizzy_w1 year ago

Hi,

I'm glad that I found this site! Yes, the price of installing pv system is still gradually falling, our saving are increasing, and that's great. I hope that people will turn to being more environment-friendly. To all reading it: we have to start being more responsible for our environment and use renewable sources of energy. It's really not that hard to design and do all the installations, especially now, that we have better tools to do it, like the apps ( this one for example http://easysolar.co/ ) that practically do everything for you, design, calculate the azimuth, provide you with simulations and financial analysis and save your time! We have to start to make good changes... Oh, and good luck to all beginners!


Elizabeth

nonford1501 year ago

Great instuctable! A few points:

If you live in a HOA, be sure to check your covenants for solar panel restrictions. Mine prohibited them; three of us proposed and got passed new covenants with defining approved installs. Not as good as all balls-out, but sufficient for a good install. BTW, this cost about $5K so try to roll this in with other changes the board has been talking about, plus be ready to go door-to-door to get people to say OK. Took us a year and 2 months - we have a small (600 house) subdivision. YMMV.

BE very sure to check with your local power provider AND your state regulator. Our local company (GA Power) won't buy back power because GA prohibits it - not that they would unless pressured by the state. Next on the list: Petitioning our local state representative to support a bill allowing it (it has failed 4 times in the past 5 years - but like all things political, squeaky wheels).

If you use am installer, make sure they can provide you with workman's comp and liability insurance proof AND call the companies and verify the policies are still in effect. Both of these are expensive and easy to cancel - if you don't check you could end up paying for a hurt worker for life or fixing damage.

Thanks this is the best I have seen I surfed the web and found such bewildering stories that it ends in frustrations
Mase7232 years ago
The Free Energy shop is developed for people who love nature and a sustainable way of living. At this moment we offer wind, solar energy and electronic gadget products. Solar Gadgets
shortw3 years ago
If i said cheap, I meant a good deal.
I actually found out as times goes on, that the panels are more cost effective now. In other words, they are cheaper per watt now then they where 1-2 years ago.
I also checked into making ' your own panels ', this is waste of your money and time. These homemade panels will fail in a very short time, since they are not sealed at all or not properly sealed.
A guy, 10 miles away from me went to do solar. After everything was done and approved, the power company changed his meter.
The meter will not go backwards, nor does he have a separate meter. If his household uses less power than the panels produce the meter will stop spinning, but he does not get credit nor does he get paid for the extra energy he is supplying to the net. He made many calls to the power company and government officials without any results. He even made a youtube about it.
Good luck with anything like this around here.
If I would do it around here, I would be doing without a building permit and I would not get it hooked up to the net. This would be the only good incentive for me around here. To much red tape in our state and county.
shortw5 years ago
I have found that the tax incentives cost you a lot of money. First off to qualify you have to get the most expensive panels and have a building permit. Your property tax will increase because of the added value. Tax incentives will be only good 'til 2015. Thinking about selling it to the utility company? You will get only 25% of the money if you sell it, than what you have to pay if you buy it from them. Also you need a 1million dollar bond for selling it. Batteries need maintenance and replacements. Solar panels are expensive per watt.
DIY Solar Jon (author)  shortw5 years ago

shortw, thanks for reading! It is true that the incentives come with some stipulations, but they are not so terrible. Let's take a look at the points you've brought up.
Panel cost: You do not need to splurge on "premium" panels - most panels are eligible, as long as you don't buy them used.
Taxes: In many states and cities (such as Virginia, where I live), tax exemption programs prevent your solar energy system from being counted as part of your taxed property value, and many townships will waive your building permit fee.
Reselling: This has a lot to do with where you live and who you buy your power from. TVA runs one of the largest buyback programs, so let's look at them as an example. TVA, in addition to providing a $1,000 bonus just for signing up, will pay you 12 cents above retail price for your energy - this is about double the price, not a quarter of it. Small, localized systems reduce a lot of strain on the grid and help the utility company build a greener image, so they are more than happy to buy energy from you at a premium.
Batteries: Most on-grid systems don't require them, but they are not annoying to deal with. AGM batteries require no maintenance and last around five years, while VRLA batteries require minimal maintenance and last for 20.
Going solar is expensive at first, but the incentive programs really do help with the cost - especially if you live in a solar-friendly state like California or Colorado. If you want to know more about incentives in your area, check out our article at http://www.solartown.com/learning/solar-panels/going-solar-what-are-the-economic-incentives. If you have any other questions, don't be afraid to ask!
I have been checking into solar panels for a while now, but could not find a place to buy them cheap. Thank you for the info.
Look here, there are a ton of instructables on building cheap solar panels, and they usually produce at least 75% of a ``premium`` one.

And they usually cost less than half.
DIY Solar Jon (author)  shortw4 years ago
I guess the question is how cheap is cheap? A long long time ago, some guy told me "you get what you paid for" it is true but it is always good to find a great deal :)
244 Jake3 years ago
But I stated with hands on just like Solar Jon is showing,
I use a weed-eater motor on my project, where I live wind is only good during hurricane seasons.
Then moved to Solar power. I bought kits off EBay, 200 watts of 0.5 volt, 3.25 watt per cells. Looks easy, works out, after you add the weather proof housing, harden glass; remember rain, hail, and snow. It is not cheaper. I did build the first 100 watt panel, yes it works. I resold the rest of kit back on EBay. Let us face a few facts, Big Company’s buy in Big Lots, like Wal-Mart! Small stores cannot compete.
Real power, that which is to supply a real house, like in Jon's photo, is not cheap, but you can do it. The cost is really cheaper with the Store bought Solar Panel then the do-it-Yourself kits. I know that sounds silly and just plain wrong. You can buy UL listed, made in the USA solar panel with big boy ratings, like 280 watts @ 35 volts for under $1.35/watt shipped to Your house. I know this because I bought 24 of them last year. You can save Big if your install yourself. But you will require a licensed Electrical guy to connect up to the gird. No city government wishes to have just anyone connecting into the grid. That can get you killed, blackout and neighborhood.
Yes, Zero Rebate if you want to use homemade cell, or anything Not UL, but only if your On-grid.
A 5 Kw system retails for $25k installed in the New Orleans area. My 8Kw cost $12k in material; mounting will be about $800. On this UL proper installed system the Fed will credits 30% if installed before 2016. Most cities and states also have Tax credits. These are 20 to 30 year systems. Do the math.
No I do not work with, own stock, have a brother or lover working for or any other interest in www.sunelec.com they are surely not the only folks either. Where there is one, there are many. You can click and see if I’m jerking your chain or not.

This will either get you hooked or not, I hope everyone wishing to live on less oil the very best of luck with what every project you do, have fun, and be safe. You can hook up any thing that makes electrical power with micro convertors, see EBay. From 500 watt DC to house wall plug. Under $100, search “Solar inverter”.

Thanks Solar Jon, for hopefully hooking a few more people to Green Power movement.

Best Regards
Big Jake
triumphman4 years ago
Here in Orange County, New York, the local Utility provider is Orange & Rockland Utilities. A Doctor here solarized his home and they only gave him pennies for his electicity that he sent back through his meter to the grid. As usual a Large Monopoly sticks it to the consumer when he tries to save energy and avoids their price per Kwh. As we speak, they are asking for another increase in rates! How much greed can there be?
DIY Solar Jon (author)  triumphman3 years ago
your buddy will break even at some and then really stick it to the util... when it comes to feed in, it really depends on location and what homeowners want to achieve. If i'm not mistaken ny has netmetering so your friend will be saving a lot of money from whatever the solar energy covers... the energy he consumes from the utility on the other hand will continue to go up at the discretion of the util overlord :(
All the more reason to go off grid like my Son. He lives in Vermont and he powers his house on 2 large panels, I don't know the output, and on cloudy days he has a generator works off the containment pond with 400 feet of head. If you are an Energy Hog you will need to spend a lot of money for panels.

No Grid Tie Here !
Hmm...much like the banks who pay you a measly interest rate and then stick it to you many times over when they issue you a credit card. Maybe the doctor should start selling his electricity to a neighbor.
DIY Solar Jon (author)  triumphman4 years ago
NY state has a pretty good program but I try to avoid the craziness of business polices and such... More headache than it is really worth. The best way to go is to eliminate the higher cost of energy we pay to utility provider, which is why I love alternative energy. It empowers homeowners and gives them the right to choose what they want to pay.

Thanks for the feedback
big corporations are always evil...(stares at oracle)
kirksky233 years ago
Hi!good day to all,i would like to say its very very good if you have solar power grid,becouse it to helpful in our solar nature for the future of our children and stop air polution,and being like a distroyer..build your own solar energy system..thanks to all.....
mcruz-14 years ago
And what happen when is raining, doesn't affect the panels? or the connections?
DIY Solar Jon (author)  mcruz-14 years ago
when it rains, energy production will be minimized but the panels themselves and connection will be safe because the connection are water tight. solar panels and the wiring are all made to withstand weather conditions to minimize and prevent damage from the elements.

Energy production will always be there but just take caution when selecting the right brand for the solar panels.
ghans_004 years ago
hi there everyone, i have a series of 3 5v solar cell 5w each. and it could produce 15v or higher on a good sunlight. but my concern is my batteries, i know they're small and can easily be charged. so i'am worried about overcharging it and eventually wear itself. Can anybody give me a charge controller circuit that will not allow flow of charge from my solar cell to my batteries when it's full.
Thanks alot guys1
kingstone4 years ago
It looks nice there, and u can benifit from the nature without doing bad to it ! I pro U up, and hope the government can devote more to this project in the near futrue, so all of us may benifit from it!
DIY Solar Jon (author)  kingstone4 years ago
I hear you kingston. I think alternative energy will really help everybody and it can possibly create more jobs to help the economy! Help the planet, help the job market, help people, win win in my opinion

Thanks for your feedback
That is great working !