Before innovations in glass, films, and coatings in the past decade, a typical residential window with one or two layers of glazing allowed roughly 75-85% of the solar energy to enter a building, which has a negative impact on summertime comfort and cooling bills, especially in hot climates.
Solar water heaters, sometimes called solar domestic hot water systems, may be a good investment for you and your family.
Active solar heating systems consist of collectors that collect and absorb solar radiation and electric fans or pumps to transfer and distribute the solar heat in a fluid (liquid or air) from the collectors. They may have a storage system to provide heat when the sun is not shining. An active system may be more flexible than a passive system in terms of siting and installation.
Your home's windows, walls, and floors can be designed to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design or climatic design because, unlike active solar heating systems, it doesn't involve the use of mechanical and electrical devices, such as pumps, fans or electrical controls to move the solar heat.
Adding (retrofitting) a solar space heating system to your home is one way to combat increasing energy costs and to raise your home's market value. The two major types of solar retrofits are active systems (requiring mechanical energy and hardware such as pumps and fans to distribute heat) and passive systems (which depend on the natural circulation of a fluid for heat movement).