ABOUT SOLAR CELLS: In the future, more homes will most likely incorporate solar cells, also known as photovoltaics. Solar cells are made of semiconductor materials (usually silicon), which absorb sunlight's energy and stores it until it is needed to power something. Unfortunately, present solar cells can only absorb between 15-25 percent of sunlight's energy. This is because they absorb only visible light; other kinds of light pass right through the cells as if they were transparent.
HOW CAN HOMES CONSERVE ENERGY? There are many ways in which houses can conserve energy. Improvements in energy-efficient lighting can reduce power usage by as much as 65 percent. In fact, if every American household changed just five of the most-used lighting fixtures to energy-efficient technology, they would save a total of $6 billion and reduce power usage by the equivalent of the annual output of more than 21 power plants. Many homes have high-performance, energy-efficient windows -- featuring double glazing or special coatings -- to reduce heat loss in cooler climates and heat gain in warmer climates. These two factors account for 50 percent of a home's heating and cooling needs. Replacing window frames with low-conductance materials like wood, vinyl and fiberglass can also improve a home's insulating capability