Abstract The energy of the sun can serve many purposes. One of them is to generate heat. Using solar collectors the sunlight is directly converted into heat. The use of solar heat has many advantages. It is a clean, quiet and reliable energy source. Nowadays the use of solar heat is widespread. In households connected to a public energy grid the use of a Solar Hot Water system can save 50% or more on the energy bill for domestic hot water preparation. The main component of the solar system is the solar collector. In the flat plate collector a solar collection device in which sunlight is converted into heat on a plane surface without the aid of reflecting surfaces to concentrate the rays. The pipe that runs across the edge of an array of solar collectors, gathering or distributing the heat transfer fluid from, or to the risers in the individual collectors is the header. This insures that equal flow rates and pressure are maintained. The blackened surface in a collector that absorbs the solar radiation and converts it to heat energy is the absorber. The ratio of usable heat energy extracted from a collector to the solar energy striking the cover is depending on collector efficiency. Important condition for energy gain level of solar system is optimal placing and orientation of absorber surface. An absorber does not necessarily have to be orientated exactly to the south in order to serve as a mounting surface for solar collectors. Optimal collector's slope for maximal energy gain is 45°. The situating the collector field on the balcony railings of urban build-up areas’ blocks of flats can by an advantageous choice for renewable energy large scale implementation. Important condition for collectors’ placement of the balcony railings is their sufficient surface for installation needful number of collectors from the view of the solar system energetic production.