Many solar systems require little or no maintenance to operate smoothly throughout the year, but you should have them service occasionally. Dirt, leaves and dust can accumulate and reduce the amount of power that your system can produce. Have a licensed installer come out regularly to preform maintenance on your system.
CNN’s Schams Elwazer shows how architects turned to traditional Islamic designs to make buildings more sustainable.
You should never feel pressured to buy something, especially an expensive solar energy system. These types of salespeople are pretty common in this industry. You can tell them you'll be back later, and they should be fine with it. If they are persistent about making a deal now, tell them that the deal should be just as good in the future. Making decisions under pressure can be more costly later on.