Every solar dealer is going to tell you that their system is the best. But would you really know the difference ?

Since 1997 we've watched the solar electric industry grow from just a handful of reputable solar dealers to literally hundreds of "Solar Experts" that all have one thing in common, they all claim to have the best solar system on the market but very few of them will tell you why their system is the best. 

The following document contains rock solid information that will help you clear the smoke and mirrors, so that you can make an educated decision on whose system truly offers the best investment for your money and what companies are most likely to be there years from now if you need their services.

Asking these ten important questions can save you literally thousands of dollars and headaches on the purchase of a solar system for your home or place of business. (Updated on 8-16-2008)


Print and keep this document, it makes a great guide for protecting yourself when shopping for a solar system !

1. What is the minimum warranted power of the solar panels that the dealer/installer is trying to sell you ? Most consumers are not aware of the fact that they could for instance be paying for 200 Watt solar panels and only be getting 180 Watt solar panels ! The discrepancy is known as "peak tolerance rating", "minimum power max", "minimum warranted power" or "negative tolerance rating". When shopping for solar panels, what you want to look for is the highest minimum warranted power rating, the lowest negative tolerance rating or the lowest peak negative tolerance rating.

A solar panel manufacturer's claim of having a high efficiency rating is worthless if the solar panel has a poor minimum warranted power rating.

What all this means is that the solar panel manufacturer offers a warranty that states that their solar panel's actual power rating will not be less than a certain amount out of the box. So if a 200 Watt solar panel has a negative tolerance rating of 10% then their 200 watt panel is guaranteed not to have a power rating of less than 180 Watts right out of the box. In our opinion 10% or even 8% is not so great when you consider that other solar panel manufacturers have a negative tolerance rating of only 5%

While shopping for a solar system, you may hear a dealer boast about their solar panel's high efficiency or higher PTC rating or better performance in hot weather but if that panel has a negative 10% tolerance rating, then in our opinion, those claims are worthless. IF YOU ONLY ASK ONE QUESTION OF YOUR SOLAR DEALER, YOU HAD BETTER MAKE IT THIS QUESTION, BECAUSE THE ONLY POWER THAT YOU'RE GUARANTEED TO GET FROM A SOLAR PANEL IS THE "MINIMUM WARRANTED" POWER RATING !

Smart Tip ! When shopping for a solar electric system, always insist on seeing the solar panel's specification sheet and look for the minimum warranted power rating because that's all the power that you're guaranteed to get.


2. What is the PER WATT PTC rating of the solar panels that the dealer/installer is trying to sell you ? In an effort to create a level playing field, the state of California as well as many other states require that all solar panel manufacturers submit their product's operating specifications. These specifications are compared to real world performance ratings that have been determined by an independent laboratory called PVUsa before they are approved for the state's program. PVUsa uses more stringent conditions than the manufacturer uses and assigns a PTC rating or (PVUsa Test Conditions rating)

So a solar panel that has a STC or (Standard Test Conditions rating) of 170 Watts might have a PTC rating of 149 watts. The PTC rating along with the efficiency rating of the inverter is what the state uses to determine the cash rebate. So the higher the PTC rating that a solar panel has, the higher the cash rebate that goes into your pocket. So needless to say not all solar panels are created equal.

When shopping for a system you will rarely see two systems that use solar panels with exactly the same wattage ratings. For example, one system might use (20) 175 watt panels and have a total DC Watt rating of 3,500 watts and another system might use 170 watt panels and have total DC watt rating of 3,400 watts. So how do you compare the each system's true CEC performance and the amount of rebate per watt when two different wattage rated panels are used.

Simply visit the California Energy Commission's website at http://www.gosolarcalifornia.ca.gov/equipment/pvmodule.php and look up each individual panel's PTC rating. For example the 170 Watt panel might have a PTC rating of 152.5 Watts and the 175 Watt panel might have a PTC rating of 154.9 Watts. Simply take the 170 Watt panel's PTC rating of 152.5 and divide it by 170 watts and you'll get a ratio of .897. Next do the same for the 175 Watt panel. 154.9 divided by 175 Watts gives you a ratio of .885. Obviously the higher the ratio, the higher the per watt CEC rating.

Along with a high PTC rating it is also important to check what the manufacturer in guaranteeing that you'll receive. Again, if you're buying 190 watts but the manufacturer is only guaranteeing that you'll receive 171 watts due to a poor negative tolerance rating, then the PTC rating is meaningless.

Smart Tip !
When shopping for a solar electric system, always check the PTC rating and the warranted minimum power rating of While some brands only offer a 20 or less warranty. The solar panels that are used in the system.


3. What is the power production warranty of the solar panel that the dealer/installer is trying to sell you ? Nowadays, standard Monocrystalline and polycrystalline solar panels both have established proven track records with life expectancies that exceed 40 years. Manufacturers of these proven technologies are now comfortable offering warranties of 25 years or more.

Recently, relatively new technologies have been developed that have not been on the market long enough to establish a performance record, so sometimes you'll see solar panels with warranties of less than 25 years. You may be thinking 20, 25 years what's the difference ? But what you need to ask yourself is, in such a competitive market, why would a manufacturer offer a 20 year warranty when everyone else is offering a 25 year warranty. When you consider that established technologies should last 40 years, the answer should be pretty obvious.

Smart Tip ! While on the subject of new technologies. Although we're all in favor of innovation, obviously we're against using customers as guinea pigs on new unproven technologies.  Nowadays a lot of manufacturers and their dealers are making some pretty lofty claims about performance which may be true in the lab, but remember you are investing a lot of money into the purchase of a product that will sit in the blazing sun, the pouring rain and the relentless wind for the next 30 to 40 years.

Conventional silicon solar cell technologies have proven track records which have spanned decades. Many of the new technologies that some of our competitors are offering have comparatively no track record. And are being offered by manufacturers that have appeared on the solar market out of nowhere in the last two or three years.

In the past ten years we've seen many solar dealers and manufacturers come and go, leaving the poor consumer who purchased their products with no support and no warranties. You have to ask yourself, Since the average solar panel's life expectancy is up to 30 to 40 years, is it worth the risk of investing in a product that might give you a 2 or 3 percent performance gain when it is being manufactured by a company that have only been in business 2 or 3 years ? In our opinion, the way many of these companies come and go, it's simply not worth the risk. Sticking with established manufacturers with proven track records that use conventional high performance technologies is the safest way to protect your investment.

Smart Tip ! When shopping for a solar electric system, always look for the solar panels that have the longest factory warranties possible. 25 years should be the minimum. And beware of dealers that offer their own warranties beyond the manufacturers warranty. A 30 year dealer warranty may sound good at first glance, but do you really believe for a moment that any dealer will be around 30 years from now !


4. What is the efficiency rating of the solar panels that the dealer/installer is trying to sell you ? Solar panel efficiency ratings are important because the higher the panel's efficiency, the more power the panel will produce per square inch of active cell material which results in less roof area that is needed to produce the same amount of power. Typically the highest efficiencies come from solar cells that are cut from solid ingots of silicon. A few manufacturers have developed technologies that avoids the high cost of cutting solar cells from solid ingots of silicon, but they do so at the cost of efficiency.

Typically, manufacturers that avoid using solar cells that are cut from a solid ingot of silicon are simply trying to reduce manufacturing cost. This would be great if the savings were passed on to the consumer, but in many cases the dealers that offer these lower efficiency solar panels use their lower cost to improve their margins instead of offering their customers a lower price. Why pay the same or more in many cases for a system that includes lower efficiency solar panels when you can buy a system that uses higher efficiency solar panels.

One such manufacturer of solar panels that does not use solar cells that are cut from solid ingots of silicon, currently makes the claim that their solar panels have one of the "quickest energy paybacks". What they mean by this that they use less energy in the manufacture of their product when compared to conventional solar panels, so their panels will have to spend less time in the sun in order to recover the energy that it took to manufacture their panel.

That does not mean that your payback as a consumer will be shorter if you buy their panel. I bring this up because we have talked to several customers who were either misinformed or misinterpreted the manufacturers claim to mean that they would recover their investment sooner. That is simply not the case !

Also be careful when a manufacturer or dealer uses terminology like "Highest efficiency to date" or "Highest efficiency yet" or "Highest efficiency so far" especially when they don't bother to mention what that efficiency level is.

Do they mean, "Highest efficiency to date" for their product only ? (which may not be saying much when compared to other technologies) or are they saying that their product offers the highest efficiency in the industry, who knows ? The best thing to do is ask the dealer what the efficiency is of the module that they're using in the system that they're offering you.

Smart Tip ! Always ask your dealer to provide you with a factory printed specification sheet that lists the solar module efficiency, not individual cell efficiency. If the dealer cannot or will not provide you with a factory printed specification sheet that lists the total module efficiency, then shop elsewhere !


5. What is the efficiency rating of the inverter that the dealer/installer is trying to sell you ? Inverter efficiency ratings are important because the higher the inverter's efficiency, the higher the cash rebate from the state ! All inverters that have been approved for the State's program have been tested and have been given a weighted efficiency rating by the State. Inverter efficiencies range from a low of 89% to a high of 96%. That may not seem like a wide range but when you consider that a 7% difference in a moderately sized system can mean a rebate difference of up to $700.00 to $800.00.

Smart Tip ! When shopping for a solar electric system, always try to buy the highest efficiency inverter that you can get your hands on ! Doing so will mean more rebate money in your pocket and more power production over the life of the system !

6. Are the mounting racks that the dealer is trying to sell you professionally manufactured medium to heavy duty products or will the dealer/installer provide you with home made or light duty racks ? Would you know the difference between a home made or light duty mounting rack and a professionally engineered heavy or medium duty mounting rack ? We see this sometimes with dealers that perform installations. The quotation will list a specific brand of engineered aluminum mounting racks, and the installer will show up with a chop saw and a bunch of inexpensive steel galvanized U-channel. Sure it will work, but watch out in high winds or years down the road when the frames on the solar panels begin to corrode.

In the last couple of years a few new manufacturers have come on the scene offering to sells solar dealers and installers mounting racks at a much reduced cost. Great for the dealer/installer but as you'll see, maybe not so great for the consumer. What these manufacturers offer are light duty racking systems that used far less aluminum and were far more flimsier than the heavier duty versions. I don't know about you but the last thing that I would want securing tens of thousands of dollars worth of solar panels on my roof is a set of lighter duty racks. In addition to using lighter gauge aluminum, these type of racks typically require many more penetrations through your roof in order to beef up the racks rigidity.     

Smart Tip ! Always insist on a professionally engineered and manufactured medium to heavy duty mounting system. Never allow an installer to talk you into his or her brand of home made mounting racks without the proper engineering. Simple steel U-channel rails were not specifically designed to mount solar panels. If something were to go wrong with this type of mounting system, and your solar array detached itself and became air born you would be wholly liable. Always look for the manufacturers sticker or label on the mounting system and specify only medium to heavy duty mounting racks and components.

7. Does your dealer operate out of a commercial facility ? In other words does he work from at least an office with a warehouse area. Or does he operate from a spare bedroom, automobile or worse ?  Does the dealer have a true service center with a full time factory trained technician at their facility ? Does the dealer have any support staff at all ?

One of the biggest mistakes that a consumer can make is to buy a solar system from a company without visiting the companies place of business. Customers will simply set up an appointment in their home, listen to a short presentation, write a check and sign on the dotted line, never looking into the company that their buying from. Is the company even for real ?

Is the company financially solvent enough to honor the purchase agreement when it come time for delivery ? Does the company even stock the products that you've just paid them for ? Sure it might be convenient to purchase your solar system from the comfort of your home, but how could you possibly have even a glimpse of who your really dealing with without visiting the companies facility.

To make matters worse, some manufacturers are attracting new dealers by boasting that they'll ship their products directly to the customer's doorstep alleviating the dealer's need to warehouse any inventory. Do you really want to buy from a company who can't afford to warehouse inventory ? Remember these systems typically have 30 to 40 year life expectancies. When shopping for a solar system, always search out dealers that exhibit the financial strength today that increases the likelihood that they'll be around tomorrow.

Smart Tip ! Always visit your dealers facility and always insist upon seeing the inventory of products that the dealer will be installing on your home. A couple of hours invested in a trip to your dealers place of business could save you years of grief down the road ! 

8. Will the solar panels that your dealer is attempting to sell you still have a warranty 3 to 5 years from now ? In light of the current economic crisis, when you consider the hundreds of inexperienced overseas, manufacturers that are dumping thousands of cheap non name brand solar panels on the U.S. market, you can bet your bottom dollar that thousand of U.S. customers are going to be left with un-repairable, non working solar panels with no enforceable warranties.

For many new, small solar dealers, adding these cheap, non name brand solar panels into their product mix is seen as a quick and easy way to improve their bottom line in a tough economy, so these solar panels are beginning to penetrate the market place.

The unfortunate truth is that many consumers have no idea what brand solar panels were included in their systems. The surprising conclusion is that the only thing many of these consumers know is that they bought a "solar system".

To make matters even worse, if you search the Internet or take a closer look and the quotes that many solar dealers are providing, you'll find that many dealers have begun the practice of not even mentioning any brand names at all, referring to the solar panels as only "high quality" or maybe mentioning the quantity and wattage of the included solar panels. One Texas based solar dealer that we recently discovered on the Internet actually states in their fine print that "they reserve the right to choose the type of equipment installed" Wow, talk about writing a blank check.

Smart Tip ! Always demand that your dealer provide you with the name brand of the solar panels, inverter and mounting racks that will be included with your solar system. And always, always, always read the fine print on the quote and especially the contract. If you find any kind of language that allows the dealer to substitute the quoted name brand product for some other product or if the dealer only provides you with a description such as "220 watt high quality solar panels" leaving out the name brand, then run don't walk to the nearest exit.

9. Is your dealer a legitimate business or are you being scammed ?
This sounds pretty harsh but you would not believe how many consumers have been ripped off by people claiming to represent what turns out to be fake solar companies. When shopping for a solar system we cannot emphasize enough ALWAYS RESEARCH THE SOLAR COMPANY'S BACKGROUND. Never write a check or give your credit card number out before doing your homework.

Just like every new industry in the past, especially those that involve high dollar items, the thieves and scam artist have now come out of the woodwork. Everything from outright financial scams where a salesperson comes out to your home, takes your deposit and is never to be seen again to companies that are simply lying about their history and experience.

Here are some fictitious examples of tips that can be used to check out a company's background:

A. If your dealing with an Internet based company that claims that their website has been "America's Solar Shop Since 1998" lets say, then check out the company's domain registration at http://www.networksolutions.com  Under the bold heading in black capital letters titled "RESOURCES" you will find the link "WHOIS Search" in blue. Click on that link and enter the company's domain name. For example our company has been on the Internet since 1997 so if you were check us out you would type in solarhome.com. On about the middle of the page you will see the words, "Record created on" and then a date. This is the date that the domain name was originally registered or it is the date that the current owner took possession of the domain name.

B. Whether the company that you're dealing with has a website or is simply brick and mortar based, most established companies have a record with the Better Business Bureau. No company is perfect and depending on the length of time that they have been in business you may see a few complaints. The question is how many complaints over what period of time and were those complaints resolved ?

When checking out a company's BBB record, you will want to visit the specific BBB website that handles the town and state that the business is located in. For example we own Discount Solar Supply if we had an office located in Salt Lake City, Utah then you would want to visit the Salt Lake City Better Business Bureau at http://www.saltlakecity.bbb.org/ next click on the orange link titled "CHECK OUT A BUSINESS OR CHARITY" next enter the name of the business where it says "search for:" In this example you would enter Discount Solar Supply then select the state from the drop down box (In this example the state would be UT for Utah) Now keep in mind that we do not have an office in Utah so whatever companies you see listed have nothing to do with us. Click on the blue link for the company and there you will see the BBB rating and the number of complaints that the company has had in the last 36 months.

C. There's a neat little website called the "Wayback Machine" that can literally take you back year before year to archived pages of a company's website.

To use the "Wayback Machine" simply visit http://www.archive.org/web/web.php type the domain name of the website in the box. The box already has the prefix http:// so simply type in www. followed by the domain then .com or .org or .net then click on the "Take Me Back Button"

Next click on the year that you want to check out.  Note: Depending on when a website was submitted to The "Wayback Machine" a website may not display all of the years that a company has had a website on the Internet but what is displayed is what the website consisted of at the time.

If the company was selling product that has at least something to do with solar and you've used the other tips listed above then you're probably okay. On the other hand if the company claims on their website that they have been "selling" solar since 1999 but you used the "Wayback Machine" and discovered that the website was actually a non-profit purely informational organization that sold absolutely nothing during the time that the current company claims to has been in business then I would say that the dealer would have some explaining to do. Did the dealer simply buy the domain from the non profit organization and is now being deceptive about their history ? Probably.

D. Does the company claim to be a licensed contractor ? If so most states require that the company post their contractor's license on all of their advertising including any website. If the dealer claims to be a contractor but doesn't post his or her contractor's license, ask him or her to provide you with the number and look up the number on the particular state's contractor's license board website. If the company claims to be a contractor but refuses to provide you with a contractor's license number, the company really should be reported.

E. Lately there's been a crop of companies that are calling themselves Corporations in an effort to appears more established than they really are. If you are dealing with a company that is using the "Inc." designation check with the Department of Corporations on the Internet in the state that the business is located in and look up the company's corporate filing. We're finding more and more businesses that claim to be Corporations when in reality they are not. In fact some of these "Corporations" don't even possess a valid business license or resale permit.

F. A deception that is gaining in popularity among dealers that are new to the industry is to claim that their company has been in the solar business far longer than it really has. For example, companies will post statements on their websites, business cards or letterhead like "Serving you for the last 25 years" or "Since 1998" or "Celebrating 10 years in business"

The question is "serving you" doing what ? or "Since 1998" selling what ? These companies have a magical way of morphing previous years of totally unrelated experience selling camera's or memory chips or landscaping or roofing into experience in the solar industry. The roofing industry might have a little bit to do with solar but landscaping or memory chips ? Don't think so. The plain truth is that more than 95% of the solar dealers that are in business today, entered the solar business within the last two years.

So in most cases you're are being deceived, if your dealer is claiming more than 2 or 3 years of experience at selling solar. Again use the Wayback Machine mentioned above or check the dealers domain registration or the contractor's license if he claims to posses one. Or check the business license or corporate registration. Again the Wayback Machine may miss the first year or so that a website existed on the Internet, but if your dealer claims that his website has been selling solar since 1996 and the first record of the website's existence on the Wayback Machine shows 2002 then chances are the dealer is probably lying to you. 



It doesn't take much nowadays to set up a web site from a spare bedroom, have a few business cards and brochures printed, get a custom embroidered shirt made, and call yourself a renewable energy dealer. So called "dealers" like that are cropping up by the dozens every day.

Don't get us wrong we're not trying to make it difficult for the little guy who's just getting started, we just feel that it's important for an individual to have a certain level of integrity, competency and commitment to the industry before they identify themselves as a renewable energy dealer.

At the same time, we do not feel that this is the type of business that an individual can start without previously having received professional training and experience. 

After all, you as a consumer are not buying crown molding or windows, you're buying a high energy device that can be dangerous if installed improperly. Take your time and protect yourself. By asking these ten simple questions and following the tips that we have outlined, you can be confident that your experience with renewable energy will be pleasant, rewarding and safe.






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