During the last decade, regulations designed to change the way of designing, building, maintaining, renovating and demolishing buildings and their surroundings have been developed at European level. However, sustainability targets shift throughout the life of a building and design solutions should go beyond strict compliance with each country's regulations. This study prioritises a building's energy behaviour during its use. It demonstrates the value of combining simple passive strategies with thermal simulation tools in standard architectural design practice. To achieve this, we started from the conventional design of a house in the North of Spain, applying passive techniques to achieve energy savings and environmental improvements that exceed regulatory requirements. Simple heating and cooling practices are incorporated into the design. The final house combines all favourable actions that manage to reduce consumption, especially during the most intense winter period. The final design is fully south facing, with an additional 20% glazing in the north and south facades, a 35-cm lintel in the window frames and an additional 2 cm insulation on the facade. Simulation reduced overall thermal consumption by almost 13%. The embodied energy used for the improvements is barely significant. Although the additional investment is arguably not profitable in economic terms, the increased investment is minimal in comparison with total investment in the building. (C) 2011 Elsevier B.V. All rights reserved.