Always use non abrasive cleansers on your solar panels. An abrasive cleaner can scratch the surface of the panel and cause permanent damage and affect how well the solar panel works. There are commercial cleaning solutions to use or you can use a pool skimmer with a very soft cloth on it.
Panels have to face the sun to draw power. You get the energy from the sun, so it's important for the panels to be located in an area where they can get all the solar energy possible.
You might be wondering how you can use solar energy, without having to spend a fortune. Solar energy systems can be expensive, but they can also be very affordable. Try using solar powered lights on your walkway or around your yard. You can also add solar panels slowly to your home overtime to bring down some of the costs little by little.
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The best time to incorporate solar power into the design of a home or building is in the initial construction. Windows are best facing south to let maximum sunlight (hence greenhouse heat) in during the winter. Likewise, avoid windows facing directly into the summertime sun to keep things cooler, so less power is needed for fans or air conditioning. The maximum roof space, however, should always get sunlight exposure.