The Complete Guide to Installing A PV (Photovoltaic) Solar Panel System

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The Complete Guide to Solar Panel’s Video

In case you don’t want to read the book below… here’s the movie version. It doesn’t include everything… but hey, you don’t have to read!

http://youtu.be/W8N5iN_aRXs

So, you’re interested in getting a solar panel system for your house? Let me be the first to congratulate you, and also console you. After spending over $30,000 to install a 10,000 watt system on my roof I’ve learned a lot! So, hopefully I can help shorten your learning curve by at giving you a few tips and tools and giving you a set of things to be on the lookout for. You’re gonna need it! So let’s get started…


Installing the Solar Panels

Can I Get A Solar Panel System?

Before I decided to get a solar array I had no idea it was such a big deal. But there were a number of things that had to be expertly evaluated before we could even consider putting panels on my roof.

First, they had to come out and do a site survey. A engineer had to actually climb up on my roof, take measurements, inspect to see if we have visibility to the south, and use this funky solar pathfinder device to determine the times of day that particular areas would be shaded.

Solar Pathfinder

I went up on the roof with him and learned how this worked. It was actually really cool. He went to the four corners of where the solar array was going to be installed with the Solar Pathfinder, and with it point towards the south it has a series of marks on it and a glass dome which reflects anything that would be throwing a shadow. You basically look at the reflection and see what time of day the shadow might affect that spot.

If you’re going to get funding assistance in the form of any kind of rebate, the electric company is going to require that your roof is pointing in the right direction. This means it must be facing south within about a 20 degree window. If they can’t point the panels in that direction, you might as well not do it because your solar generation drops dramatically. Same goes for shade. If you’ve got a building beside you, or trees that tower over the house, you’re done.

Even if your roof points south, and nothing’s blocking the sun you still need to have an engineering survey done to determine if your roof can bear the additional weight! Our massive solar array weighs tons. Literally. Luckily, it only adds about 5-6 pounds per square foot of roof loading, so most roofs should be able to take it.

How Big of a Solar Panel System Do I Need?

This is a tricky decision. For me, there was an upper limit because we were going for a partial rebate and it maxed out at 10kw. So to some extent figuring out what you need is narrowed down by how much room you have and cost. But you also need to take a look at your previous year’s electric bills, find out what your electric rates are, and research what the projected generation will be for the size of system you’re thinking about.

Here’s a site to let you calculate production for your location. Just pick your country and state. You’ll come up with an estimate that looks kind of like this:

Solar Production Estimates

It’s a royal pain in the ass. So I built a big monster spreadsheet to calculate mine.

To give you a rough ballpark though, our house is over 4,000 sq ft., we’ve got a lot of stuff in there like a pool, two fridges, two A/C units, 7 TVs, and a bunch of electronics, and our 9.5kw system isn’t projected to completely offset our power usage. It would take closer to 14kw in theory.

For an average home of say 2,000 sq ft. you could probably get off the grid with 6-7kw. As far as we’re concerned, since we maxed out on the rebate for this year, we’re considering doing it again next year to be completely self sustaining.

Solar Panel System Tips and Tricks

Oh boy, there is a lot they aren’t telling you! For example, one really good thing is that these systems are mostly guaranteed for 25 years! What isn’t really talked about is that its the solar panels that are warrantied for that long, but the inverters are not. So when you’re doing your ROI calculations you need to include the fact that you’re going to have to spend thousands of dollars somewhere in the middle of the lifecycle for changing out parts.

Sunny Boy Solar InverterIn my case, the Sunny Boy 8000 will probably last 10-15 years, and a new one currently costs around $3,000 installed.

Speaking of the Sunny Boy, I should explain that the reason you need an inverter is that the solar panels put out DC current. This is like the current that comes out of a battery. But houses use AC current. So the inverter takes care of the conversion. There are two different kinds of inverters that are currently in use.

Solar Panel Inverters vs. MicroInverters

Our SunnyBoy 8000 is rated for 8000 watts of incoming power. But due to some sort of magical logic that I can’t understand, its OK that we are actually funneling 9,750 watts into it. Anyway, the thing about inverters like this is that the solar panels must be fed into it using equal sized arrays. In our case three strands of 13 panels each.

A normal inverter is going to have a couple of drawbacks when it comes to efficiency. Lets examine just one of our 13 panel arrays. In a string of thirteen 250 watt panels all of the panels will not be putting out the exact same amount of power at the same time. One might be making 99 watts while another is making 105, etc. But since they are all in a single string, the inverter is going to basically dumb them all down to the lowest panels output. That means you’re losing a few watts all the time.

Also, if a single panel in our string of thirteen happens to die, the entire string stops producing altogether. That means if we lose one panel we lose 1/3 of our energy production. Yikes!

How Solar MicroInverters Work

An answer to the efficiency problem comes in the form of micro-inverters. Instead of stringing multiple panels together and putting them through one big inverter, micro-inverters are installed on every single solar panel. This allows each panel to contribute 100% of its production to the home, and if one fails it doesn’t affect the output of any others.

Choosing between Inverters and MicroInverters

Each type of inverter has its own benefits. While micro-inverters are more efficient, they are also more costly. In our case they would have added over $2,000 to the installation (which buys a lot of electricity). There would also be 39 inverters and a lot more wiring that have to be mounted and routed. Yikes! Big inverters like the SunnyBoy might weigh 140 pounds, but they get mounted in one spot and with minimal wiring. They are also extremely reliable, having been around since the beginning of the industry.

Other Things To Keep In Mind

Another thing no one bothered to mention to me was that the roof on your house generally doesn’t last as long as these systems. So let’s say you have a 10 or 15 year old roof. There is NO WAY it’s going to last as long as the panels. What do you do then? If you have to do any work on the roof you have to deal with the solar array first. I still haven’t figured out what I’m going to do about that.

Solar Panels on the Roof

Who’s going to look after the system? And how? In our case since we have a flat roof I also installed a hatch so that I can get up there and mess with things whenever I want. I stayed at home and participated during the install so I could learn how things were connected, and if something needed minor repairs I could do it myself.

If you have a pitched roof, you probably don’t want to be getting on it to service your panels. So make sure the company you choose has been around a long time so you don’t have to rely on service from someone else.

How Long Does It Take To Install A Solar Panel System?

Installing the Solar PanelsThe good news is that it only took about 2 full days for Axiom Solar to do the install on my roof. If you’re in the Dallas area I highly recommend those guys. They did a great job. And I didn’t get paid a dime to say that.

The bad news is, that the answer isn’t that simple. After we did the site survey and worked out pricing and all that, we had to sign contracts. Those contracts had to get sent off for approval to the electric company because we were going to be tying into the grid. And because they were picking up the bill for about 40% of the system, they had a bunch of rules about how efficient the systems have to be.

Meanwhile, we had to have the structural engineer come to the house to determine if the roof could bear the weight, and permits had to be pulled with the City of Dallas.

By the way, if you’re wondering if you can do all this yourself – the answer is no. Next question!

Solar Panel System Shutoff Switches

All of those things took weeks to complete, combined with the fact that Axiom has a very packed install schedule meant it took a couple of months before we could get the system installed. AFTER we were installed, there were several inspections from the city and the electric company before we could turn it on and actually generate power.

So, lets say it takes about 3 months to get the system installed.

How Much Does A Solar Panel System Cost?

The cost of the actual system probably won’t vary that much from place to place, but there are a lot of options, and there are different incentives from place to place.

In my case our system cost almost exactly $30,000, and we got a 10kw system. If you were to piece it all out, probably around 60% of the cost is just the hardware. And believe me, the labor cost was worth it! You should have seen all the equipment and people it took to get the job done. They had a machine that lifted the panels and tons of bricks onto the roof, then they all had to be carried over and installed. Plus the framework for holding the panels had to be built on the roof, and all the electrical work had to be done…

Wiring Up the Solar Ballasts

The reality is, it was worth every penny. It was just a lot of pennies!

Now, out of the $30k, our local energy company, Oncor, picked up the first $14k. I had to pay $16k out of pocket, and at the end of the year we get a 30% federal tax write off, bringing my net cost down to around $11,500.

According to my spreadsheet, this equals around a 10 year payback for a system that is guaranteed to last 25 years. By the way, the actual guarantee is that the solar panels will still be producing 80% of their original output 25 years from now, or they’ll replace them. Assuming the Chinese company we got them from is still around to warranty them. That’s a big if.

More important than the 10 year payback is the fact that my investment of $11,500 is expected to generate a return of only about 5%. That’s the equivalent of buying a decent bond, but frankly it’s not as risk free. A lot of things could happen to ruin my return, so the risk is not really in line with the reward. From a purely monetary standpoint, over a 25 year period you’d get at least double the return if you put that money in the stock market.

And that’s what makes solar so iffy! With today’s level of solar efficiency, and everything it takes to install it, it’s really not a good investment unless you are just committed to going green. However, if you can afford to do it, it is also a form of insurance against the potential of skyrocketing energy prices.

How Much Power Does The Solar Panel System Generate?

Well, so far according to our reporting our system has generated over $360 retail dollars worth of power in the roughly 2 months its been operating. That’s pretty good! But one thing I quickly learned and which I found astounding was just how poorly these systems perform when it isn’t a beautifully clear day.

For example, this is a sample graph of power output for last month. You can clearly see the two days that were rainy. There was almost no power generated!

Rain Days

That explains why these systems are great for climates like Texas, Arizona, Southern California, but horrible for places like Seattle or San Francisco.

Here’s a closer hourly look at the production on a typical sunny day in Texas.

Typical Sunny Day

And here’s what it looks like on a rainy day.

Typical Rainy Day

It’s enough to make you cry. ;-)

I hope that answered a lot of your questions, but I’m not foolish enough to think it would answer them all. So ask away in the comments below and I’ll respond to them as best I can.

The Solar Panel Photo Gallery

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About The Author

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John P. is CEO of Livid Lobster and co-host of Geek Beat TV. You can also find him on Twitter and Google+.

6 Responses

  1. P. Dennis Aquino

    Hi John P.
    You mentioned in the video that your home most probably require 14 kw of solar panels for your entire electricity requirement. Does that include night time use? It wasn’t mentioned how you store the electricity for use at night time or are they basically just used during day time?The reason I ask is, is there an efficient way to store the solar energy for use anytime so to be completely off the grid?

    I’m a proponent for using and promoting the use of renewable energy where I live and believe that we have to go green to do our part in saving the planet, but when asked about use of solar panels for home installations, am stumped since they can only be used during daytime. It helps that where we are night time use of electricity is way cheaper than day time.

    Anyway, have been enjoying your show (geekbeat tv). More power!

    Thanks.
    Dennis Aquino

    • Avatar of John P.
      John P.

      Yes, the 14kw would be for total energy usage at our home, day and night. We could indeed store energy if we wanted, but it would require $10,000 worth of batteries, which would take up a lot of space and have to be changed out ever 5-7 years. Definitely not worth it if you have an electric grid you can tie into.

      What we are doing is creating most of the energy we use during the day, and selling the excess back to the electric company in the form of credits that we then use at night. This saves us the space and money that would otherwise be needed to care for batteries. Hope that helps explain it!

  2. Tammy

    You did a great job giving an overview to a complected subject matter. I currently design solar arrays for a company where I live, and it still amazes me what factors need to be taken into account before a project can even start.

    The rainy days cause such a significant drop in production because of the cloud cover. The clouds cause the light to diffuse (or scatter), so you are not getting the direct radiation you would get during clear days. The other thing to keep in mind is that these systems tend to work better in cooler climates. Just as computers function better when it is kept cool, the same goes for solar arrays. So while you mentioned places like Seattle not being optimal (I’m assuming because of the clouds), places like the North East are good, because of the cooler temperatures, and also the snow. During winter, the snow can actually deflect the light back onto the panels creating a possible small increase in production.

    Please keep us updated as to how your array is doing.

    Best of luck!

    Tammy

  3. Kim Toufectis

    A fine summary of a complex undertaking. Great job at raising the many questions we didn’t even know we should ask before going solar… We went solar in Washington DC last year and learned many of the same lessons you did. Our system is 2/3 as big, which roughly matches the demand for our smaller home (some months we pay the utility for power, but other months they provide us a credit as we feed more power into the grid than we draw out).

    Our system replaces your “Sunny Boy” inverter box with microinverters, which attach to the underside of each panel. We think they’re worth some extra up-front cost because (a) they are warranted to last for the same 25 years as the panels, (b) we have no garage or other unfinished area for that big inverter, (c) they let each panel operate independently (more objects cast shadows on one or more panels on our roof than yours), and (d) they tell us what each panel generates (helping to get the manufacturer to honor their warranty to replace an underperforming panel if need be).

    Several northeastern states have markets for trading Solar Renewable Energy Credits, the “green-ness” of the renewable energy our panels produce. At least right now the DC market pays a lot for our credits, shortening our payback time to about 5 years rather than the 10 or more years you expect in Dallas.

    You note that solar panels could make re-roofing your home harder/more expensive. Our installation contract includes a clause to remove and re-install our system for a fixed $1,000 fee to allow roofwork any time in the first 10 years of operation. The extra peace of mind of that offer helped us commit to go solar, and tipped the scales in favor of the one installer who offered it.

    One more payback consideration: it’s hard to know exactly, but if you sell your home with a working solar array, it should sell for more than it would without that array. Saving $1,000+ each year would certainly affect what folks would offer/pay for a home. I’d guess you might get most of the $11,000 you paid out-of-pocket (after all incentives are credited) for your system, so if you do have cause to move away before 10 years, you’ll probably still break even.

    Please give us an update when you complete a year of operations!

    • Avatar of John P.
      John P.

      That is EXCELLENT feedback Kim. Thanks so much! This is why I love sharing what I know. Because when others do so as well we all get smarter together! I wish I had known about the $1,000 reinstall clause. Though its possible that we’ve got something similar with ours. I just didn’t notice. So many details!!!

      John P.