The current tendency of the population is to live in cities. This behavior added to the fact that the world population is still in - creasing, with a growth expectation of 1.3% from 2016 to 2050, highlights the necessity of increasing the number of buildings in the world and, as a consequence, the increase of house energy consumption. Nowadays the sector of the computational de - sign is growing with a diversity of products and scopes. The aim of this study is to use one of these software to optimize the characteristics of a house in order to reduce the energy consumption of the place people live in, work in and spend time in. The use of Grasshopper has permitted to simulate the energy consumption of a house located in Barcelona and thus to optimize it s characteristics in order to reduce its energy consumption, with a final reduction of 2734kWh/year, which represents a reduction of 87.6% between the non - optimized house and the optimized one. This article shows that it has been possible to use the new co mputational design software in order to reduce the energy consumption of the studied house. The results obtained show that this study can be used in future larger - scale projects in order to reduce the energy consumption in the residential sector.