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. Click here for more information on warranted minimum power.

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 (Remember the Connecticut solar rebate program uses California's data when calculating rebate amounts) requires that all solar panels be tested by an independent laboratory called PVUsa before they are approved for the state's program. PVUsa tests every solar panel using 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.consumerenergycenter.org/cgi-bin/eligible_pvmodules.cgi  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 high the ratio, the higher the per watt CEC rating.

BUT BE CAREFUL ! Solar panels are manufactured in batches or lots with each solar panel varying in performance from the next one. So it seems prudent to assume that a manufacturer would send only the best panel from a production lot to be evaluated for it's PTC rating.

So in essence chances are good that the sample that was sent for PTC evaluation will not be representative of what you as a consumer will receive out of the box. This is why it is important to check what the manufacturer in guaranteeing that you'll receive. Again, if you're buying 190 watts but the manufacturer in only guaranteeing that you'll receive 171 watts, 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 the solar panels that are used in the system. Here's a link showing you a comparison of several 165 watt solar panels that are currently listed on the state's website. Mitsubishi PV-MF165EB4 solar panel PTC rating comparison

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, we totally disapprove of using our customers as guinea pigs on newfangled unproven technologies.   Nowadays a lot of manufacturers and their dealers are making some pretty lofty claims about performance which may or 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 newfangled 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 have come and gone, it's simply not worth the risk ! Sticking with major brand, 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 solar panel warranty may sound good at first glance, but do you really believe for a moment that the 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 and the lower the roof area that is needed to produce the same amount of power as well as the higher the per watt PTC rating. (Remember in many states the higher the PTC rating, the higher your cash rebate) 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 in many cases a higher price for a system that includes lower efficiency solar panels when you can buy a system that uses higher efficiency solar panels for the same or a lower price.

One manufacturer of solar panels that does not use solar cells that are cut from solid ingots of silicon claims 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 difference of $836.92, it's nothing to sneeze at !

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 for the life of the system !
 

6. Is the inverter that the dealer/installer is trying to sell you, transformer-less or does it have a copper wound transformer ? In an effort to be competitive, many dealers have begun to offer lower cost inverters that do not include copper wound output transformers. Copper is expensive but its time tested performance in inverters is undeniable ! Before making a buying decision, always ask your dealer whether or not his inverter has a heavy duty, copper wound output transformer or better yet ask the dealer how much his inverter weighs, then ask to see the inverter's specification sheet to be sure. For example, a typical 3 kilowatt inverter with a heavy duty, copper transformer will weigh about 85 pounds !

Smart Tip ! If two dealers are offering similarly priced system, but one is offering a lightweight inverter and the other is offering a heavier inverter with a copper wound output transformer, then it is our opinion, based on years of experience in operating one of California's largest inverter repair centers that it is best to choose the dealer who is offering the inverter with the heavy duty copper wound output transformer.
 

7. 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 some of these manufacturers were offering were light duty racking systems that used far less aluminum and were far more flimsier than the heavier duty competition. 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.



8. 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 ! 

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 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 seven 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.