The contribution of waste materials to the overall energy savings in buildings with single-layer ceramic envelopes is twofold. They can not only enhance the thermal properties of the brick blocks but also reduce the total energy necessary for the brick production. In this paper the contribution of waste products to the energy performance is demonstrated for a typical brick family house in the climatic conditions of Prague, Czech Republic. The energy calculations are conducted using Energy Plus with pre-calculated parameters given by the PHPP model. Specific computational modules for the calculation of effective thermal conductivity of brick blocks are utilized as integral parts of the energy performance calculation tool. Five different types of external walls are analyzed. They are made of solid clay bricks, sawdust-lightweighted solid clay bricks and a new type of highly perforated ceramic block with improved geometry which was developed recently by a Czech brick producer in three versions, having the cavities filled with air, waste polyurethane and mineral wool. The obtained results show that perforating the bricks, together with lightening their body and applying thermal insulating cavity fillers, can reduce the specific heating demands of the analyzed building up to 79.4%. (C) 2016 Elsevier Ltd. All rights reserved.