Economical analysis of the solar heating system with seasonal storage, which was established in Edirne (41 degrees 39 ' 54 '' N) in order to provide the heat requirement of buildings, has been fulfilled. Optimum collector area for the heating system has been determined. Total heat requirement of 69% has been met by means of heating system concerning the space heating and domestic water heating. In the accordance with the results of the economical analysis. the payback time of the heating system has been determined as 19-20 years. (C) 2008 Elsevier B.V. All rights reserved.