subject: Key Points About Your Solar Panel Purchase [print this page] Key Points About Your Solar Panel Purchase
If you're planning on purchasing a solar panel system for your home to cut down on your electric bills, check the following to help you make the right choice:
Manufacturer
It is always best to know who the manufacturer is. There are more than a thousand manufacturers around the world. To ensure that warranties can be claimed without any setbacks or delays, choose the manufacturers who have ready distribution networks near your area.
UL Listing
The Underwriters Laboratories (UL) has been meticulously testing solar panels for weather resistance, performance, mounting methods and other safety considerations in its testing site in Silicon Valley. Ask if the solar panels are UL Listed.
Rated Power at Standard Test Conditions (STC)
In simple terms, this is what you will ask for if you want to buy a specific wattage. So if you want to buy a 220 watt panel, make sure that the rated power at STC is 220 watts.
Rated Power Per Square Foot
This is the measure of rated power for every square foot. It is also known as the "power density." The measurement that you will get here is important because the higher its value, the less space you will need for the panels to generate the energy you need. For example, if the solar panel has a rated power per square foot of 20 watts, you could get 220 watts out of 11 square feet.
Solar Power Efficiency or Module Efficiency (in percentage)
This measurement, in percentage, tells you the ratio of the output power to the input power. For example, if the panel generates 100 watts of output power from 1,000 watts of solar power that it receives, the solar power efficiency is ten percent. Between 10.3 up to 19.3 percent is the efficiency of most panels in the market. Pricewise, the higher the efficiency, the costlier the panel.
Rated Power Tolerance
Usually, this is seen as a numeric specification of +/- 5. This measurement means that in certain conditions, the rated power of the solar panel could either increase by five percent or decrease by five percent.
Cell Type
Thin film panels use crystalline silicon applied as film directly on the panels. These do not have crystal-like features making them easier and faster to produce. They are the cheapest but least efficient type of solar panels.
Polycrystalline (Poly) panels, on the other hand, are made up of a bunch of small crystalline silicon cells that are put together. Poly panels are advertised as cheaper than Mono panels.
Monocrystalline (Mono) panels use only one cell from crystalline silicone formed in a large sheet. Mono panels are said to be the most efficient of the three types of solar panels.
So before you start purchasing your solar panels, look closely at the specifications. Always remember that aside from shelling out a substantial amount of money, your solar panels will be with you for at least twenty five years. And good sense dictates that if you'll live with these panels for at least twenty five years, you should at least try to get to know them better.
