Solar collectors are a popular category of solar energy devices that are used to heat domestic water supplies using the power of the sun. The technology used in solar collectors (Solarkollektoren) is variable on the kind of collection device being used, with flat plate collectors and evacuated tube collectors being the two most common examples. Along with the use of photovoltaic panels to generate electricity, solar collectors are probably the most popular type of renewable energy technology that is being used in modern homes. There are also solar collectors that are used by solar power plants, where solar heat is used to generate electricity though the use of steam. In a domestic context however, solar collectors are generally used to heat water through the use of solar energy.

Domestic solar collectors fall into two distinct categories, concentrating and non concentrating. In non concentrating devices, the collection area is the same as the absorber area, while in concentrating devices there are two distinct areas. The two most popular technologies that are used in solar collectors are known as flat plate collectors and evacuated tube collectors. Flat plate collectors are the most popular type, and are fairly basic in their design. They consist of a dark flat plate absorber, which works with a transparent cover and a heat transport fluid. Different models use different types of fluid, with the most common being air, antifreeze, and water. A heat insulate backing is also generally included in these designs, consisting of either thermally stable polymers, aluminium, steel, or copper, which is placed in an insulated casing together with a polycarbonate or glass cover.

Evacuated tube collectors use a slightly different technology, with pipes used for the heating of water. Because the liquid passes directly through the pipes, this technology is an efficient way to heat water through solar energy. Some evacuated tubes are made with from a layer of glass or metal that fuses to the heat pipe area, enclosing the heat pipe and absorber in the vacuum. Others are made from glass alone, with a double layer of glass fused together at either a single end or both ends and a vacuum area between the layers. Solar collectors are becoming widely used in homes around the world, and new developments are leading to a refinement of the technology and principles involved.