Housing Energy Equivalence: A Graphical Approach

Abstract

All buildings, even the most passive, need active energy to provide habitability. Apart from heating and cooling needs, which have been broadly studied and regulated, a significant percentage of the energy consumed in housing is due to home appliances. Furthermore, this value is increasing as the design of environmental conditioning becomes more efficient. The objective of this paper is to visualize the impact of these consumptions by a graphical equivalence that uses drawing to represent the surface area of photovoltaic modules that correspond to the energy demand. With this aim, a straightforward method is proposed based on graphical means that fit well with the working practice of architects. The procedure starts by detailing the energy consumption of a home, focusing on the consumption values of all appliances and lighting. Next, each single value is converted into the surface area of photovoltaic modules required to produce this energy in one year. Finally, each appliance and its corresponding energy production area are represented graphically side by side, resulting in the housing energy equivalence. This method has been tested by a group of architecture master's students using their own homes as the case study. The results show that the energy equivalent surface area for lighting and appliances represents between 8% and 46% of the floor area of their homes. Altogether, this approach makes visible a pending question in sustainable building design − the consumption of electrical home appliances − and provides rough graphical data which is useful for pre-dimensioning in the architectural design process.