Designing a low-energy building requires the evaluation of a large number of parameter combinations. Currently, there are several software programs available that are able to calculate the energy performance and life-cycle cost. However, these programs provide little information regarding what actions will improve the energy performance and how much will they cost. An iterative software program that optimises the parameters would be a solution: however, the larger the database, the slower the data processing and optimisation. The SEDICAE project applies a new methodology based on a tabu search and a simplified method to calculate the demand. A tabu search is a good method to avoid local minima and to permit an evaluation of different solutions. The methodology is designed to estimate the annual energy demand, life-cycle cost and the energy rating. In this paper, 48 different scenarios were analysed with SEDICAE software. (C) 2014 Elsevier B.V. All rights reserved.