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Installing Solar: Things to keep in mind when comparing bids

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“Going Solar” is such an exciting decision! You already know you’re making a great financial investment decision as well as being a friend to the environment. So now you find yourself at the point where you contact different solar installers to get bids. A good installer should be able to give you a solid ball park price estimate over the phone if you provide them with your annual kilowatt usage and your address so they can look at a satellite image of you property on Google Earth. But to get an exact price quote, they will definitely have to make a site visit. So suppose you’ve received several quotes yet one is substantially lower than the others….how can this be?

This is where you have to be careful. It is tempting to go with the lowest bid, assuming that it will save you money. The old adage “If it sounds too good to be true, it probably is” definitely rings true here. It’s also true in this industry that you get what you pay for!  Unfortunately there are companies out there who will provide you with erroneous or misleading information just to get your business; or will use shoddy product and cut corners on the installation… those companies likely won’t be around in the future should something go wrong with your system and you need help.

One of the most common ploys to be aware of is “Our solar panels are more efficient than others so they will produce more power.”  This is very misleading. The efficiency of a solar panel has little to do with its power output. For example, a 300 watt solar panel is a 300 watt solar panel… it is only going to output 300 watts of power.  Therefore 2 solar panels of the same size (wattage) exposed to sunlight for the same amount of time are generally going to produce the same amount of power (kilowatt hours). The efficiency has much more to do with the physical size of the solar panel itself… NOT how much power it will produce.  If one 300 watt solar panel is more efficient than another 300 watt solar panel, that simply means it is smaller in physical size than the less efficient one.  There are however some very small differences in solar panels that may contribute to one solar panel generating more or less power than another solar panel of the same wattage (i.e. – temperature coefficient) but these are small differences and will not greatly impact the power production, contrary to what many solar installers imply.  The most important thing to remember here is that wattage is the most important consideration… a 10kW array is a 10kW array and one will not produce more than the other, regardless of solar panel efficiency.  It is also important to ensure, that the installer is using Premium Grade solar panels from a Tier 1 manufacturer that offers a 25 year linear power production warranty.  Also, ensure the solar panels have “re-insurance” to back up the warranty in case the manufacturer is not around if a warranty claim arises.

Another issue to be extremely aware of, if you are getting a roof mount system, is the type of racking that will be used to attach the solar panels to your roof. Many installers cut corners here in order provide you with a cheaper bid and win your business, but it is to your detriment. Roof mounted solar systems generally require attachments that penetrate the roofing material and attach to the roof joists or trusses in your attic.  A reputable installer will use “flashing” which is a thin metal plate covering the roof attachment point, tucked under the shingle and further secured with bead of roofing tar AND silicon rubber gaskets to ensure no leaks ever occur at the penetration point for the full life of the system. A less reputable installer will just use something called an “L Foot” without flashing which is an L shaped bracket set and drilled into the trusses from the top of the shingle, leaving an opportunity for the roof to leak at every penetration point. Most will at least use a dab of silicon on top of the lag bolt that penetrates the roof, BUT… your solar panels have a 25 year warranty and I certainly wouldn’t want to rely on a dab of silicon on top of a bolt to protect my roof from leaking for 25 years or longer… would you?  An installers cost for an attachment bracket WITH FLASHING and hardware is around $12 each versus an L Foot bracket at $2 each. Therefore, if you take a 10kW roof mount system, for example, it would require approximately 100 roof attachment points and 200 lag bolt penetrations into the roof (each roof attachment requires 2 lag bolts, if the installer is not cutting corners or using a low quality product).  That means the cost to the installer is $1200 for the flashed attachment or $200 for the L Feet. It also is much less labor intensive to install an L Foot than it is to properly install a flashed attachment bracket.  That one little trick right there allows the less reputable installer to knock approximately $1500 off your bid (parts & labor) with you being none the wiser……until your roof leaks.

Another trick commonly used by shoddy installers is to under size the inverter. It is really important to use an inverter that is large enough for your system to run at maximum efficiency. The inverter should not be sized less than 90% of the total size of the array (in kilowatts).  The inverter can be slightly smaller than your array size because there are some system losses that occur (i.e. – panel soiling, wire/connection losses, etc.) but an inverter that is too small will “clip power” on a sunny day when the sun is over head.  For example, if 10kW’s of solar panels are outputting 9kW’s of power but the system only has an 8kW inverter, then your system will only output 8kW’s because 8kW’s is the maximum output of the inverter.  In this situation, your solar panels are producing 1kW (1000 watts) more power than the inverter can handle so the inverter “clips” the excess power (to avoid damage to the inverter), thereby wasting 1000 watts of electricity at that time.  Obviously, the smaller the inverter is the less expensive it is so the installer can quote you a lower price and still tell you that you have a 10kW solar array, because you do in fact have 10kW’s of solar panels… even though it will not produce as much power as it should if the inverter were properly sized.

One final thing to be aware of… ask your installer to justify their power production calculations and make sure that all the quotes you receive use the exact same “system loss” calculations.  Many installers will misrepresent the system losses, which produces the illusion that their solar array will produce more power than the other more reputable installers.  I’ve even seen several installers say “because our system produces more power than our competitors (for whatever bogus reason), we can build a smaller system for you, which in turn saves you money on the installation cost.”  Again, total hogwash!  Bottom line is… a 10kW array is generally going produce the same amount of power as another 10kW array, if it’s properly designed and installed!  So make sure they not only provide you with the power production calculations but ALSO with their “system loss” calculations so you can verify that all installers are using the same accurate calculations and that someone is not misleading you here.

It is so important to have an excellent installer when it comes to your new solar system. The best way to find them is to ask questions. An installer worth his/her salt should take plenty of time to answer any question you have down to the very last detail…..as you can see, details are important.  Also, ask for references! These customers can give you feedback on the installation process, the efficiency of their system and if any problems arose, how they were dealt with. They are the best way to make sure the installation company has stood the test of time. Many companies can slap together a cheap installation but the few really good ones will provide an excellent product, outstanding service and be there for you down the road when and if you need them. Going with a reputable installer may cost a little more up front but is surely worth your peace of mind.

Please check out our website at www.altewindandsolar.com and our Facebook page at http://www.facebook.com/pages/Alt-E-Wind-Solar-Ltd/196202797091314 or give us a call at 970.482.SOLAR (7652).

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