This paper deals with the development of a low cost and low energy consumption air conditioning system based on the conventional central heating installations. It is aimed to convert, with minimal cost and work intervention in the interior of the buildings, the classic central heating systems into a new type system which can cool during summer and heat during winter period. In general, the above mentioned heating-cooling system constitutes an integrated new technology in building air conditioning, with good prospects in replacing eventually the conventional air conditioning systems. The experimental installation is described in detail and the experimental results are presented and analysed. The achieved energy saving is also calculated. The advantages and disadvantages of the proposed system are discussed and useful conclusions are drawn. (c) 2005 Elsevier B.V. All rights reserved.