As advancements in solar technology continue, solar companies continue to announce new solar panel models, using terminology that can leave the average homeowner feeling dazed and confused. You may be tempted to leave the choice of the solar panels completely up to your solar installer.
If youve chosen a reputable solar contractor with a proven history of excellence, like one you can find here through CalFinder, you can feel secure that youll get a quality product, but arming yourself with a bit of comparison shopping isnt a bad idea.
If youre shopping for the least expensive panel on the market, you need only concern yourself with two factors: the efficiency of the panel and the cost. A solar panels efficiency is measured by the amount of sunlight it can convert to electricity under optimum conditions, usually at the time of day when the panel is directly facing full sunlight.
The more efficient the panel, the more power it will produce each year. The efficiency of solar panels available today range from 13 percent to 18 percent. When price is the primary consideration, the PV system with the best yearly output at the best price is the system to choose.
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The least expensive system wont count for much if it breaks down quickly, however, so the third criteria to consider is the systems life expectancy, which can only be assured by a quality warranty. The power output of the panels themselves should be covered for at least 20 years. These warranties typically cover a percentage of the power output, from 80 to 90 percent. The systems components should be covered for 2 to 5 years.
There are about a dozen major solar brands on the market, using either monocrystalline or polycrystalline photovoltaic (PV) cells. Monocrystalline cells are cut from a single silicon crystal, making them more fragile then polycrystalline cells, which are made by cutting plates from silicon poured into molds.
Polycrystalline cells are cheaper to produce, but since they require connecting numerous silicon cells, are less efficient in converting sunlight to electricity than a single crystalline cell. Visually, its usually easy to tell them apart. With the exception of Sharp, SolarWorld and Trina brands, monocrystalline panels are black, while polycrystalline panels are blue.
When researching a solar panels efficiency, look for PTC ratings, rather than STC, or Standard Testing Conditions. STC watt ratings are done by the manufacturer. Often required by states before a solar panel can enter the market, PV USA Test Conditions are conducted independently.
Comparing cost per PTC figures is the best way to determine which panel offers the most efficiency at the best price. Individual solar panels range from about $400 each to $700 each. The cost-per-PTC prices range from about $2.50 to $4.50. How many solar panels to buy is another important issue as well.
While some solar companies offer comparison reviews, consumer reviews are scarce. A conversation with a reputable solar contractor is a good place to start your investigation. Be wary of contractors who only seem to know about one product. Your solar installer should be knowledgeable about a variety of options. Check out our contractor database to find one in your area.