Solar energy from the sun’s heat and light is renewable, unlike fossil fuels. The rising cost of fossil fuels and their adverse effect on the environment make solar energy more attractive.

The sun is a giant heat source. If you can collect enough solar heat, you can use it instead of the heat from a furnace. One way to collect heat is to trap solar energy with solar collectors. A solar collector allows sunlight inside through glass or plastic, absorbs the sunlight and changes it into heat and traps most of the heat inside.

Solar collectors become so hot that they can be used as heat sources for a building. There are two kinds of buildings that use solar collectors as heat sources: passive solar buildings and active solar buildings. Passive solar homes do not use any special mechanical equipment such as pipes, ducts, fans or pumps. Since the sun shines from the south in North America, passive solar houses are built so that most of the windows face south. They have very few windows on the north side. Passive solar houses use walls and floors to absorb solar energy and turn it into heat.

Some buildings use special mechanical equipment to collect and distribute solar heat. These buildings have active solar heating systems. Active systems use collectors that look like flat boxes covered with glass. Dark-colored metal plates inside the boxes absorb sunlight and change it into heat. Air or water flows through the collectors and is warmed by this heat. The warmed-up air or water is then distributed to the rest of the house just like in an ordinary furnace system. Active solar collectors are usually placed high up on roofs where they can collect the greatest amount of sunlight. They are put on the south side of the roof in a place where no trees or tall buildings will shade them.

Solar energy systems must include some ways of storing the heat that was collected during sunny weather to offset cloudy weather when no sunlight can be collected. In active systems, either hot water is moved to large tanks of water, or hot air is moved to bins of rocks beneath the building. When it is needed, the hot water or air is taken back out of storage and sent to the living areas. In a passive house, heat is absorbed by the thick walls and floors during the day. At night, when it becomes cold outside, warm walls and floors release their heat back into the room.

Solar energy is a viable and cost-effective way to heat your home. The N.C. Solar Center is an excellent source of information at www.ncsc.ncsu.edu.