Straw bale houses in a moderate climate: adaptable to meet future energy performance requirements?

Abstract

The energy performance regulations for buildings, introduced in many countries during the last decade, will be tightened in the future, even up to zero energy level. Apart from that, ancient building techniques that use renewable materials, such as straw bales, have a revival, inspired by concerns about the environmental impact of building materials. However, straw bale construction related organisations are concerned whether this building technique will survive the upcoming severe energy performance requirements. In this frame, two recently built straw bale houses in Belgium have been analysed through a post-occupancy evaluation to determine their current performance for energy, comfort and indoor air quality. Furthermore, the possibilities to improve these houses to meet future energy performance regulations have been investigated. The different steps in the strengthening of the energy performance regulation towards 2021 set by the Flemish government are used as reference points. Different scenarios for improvement have been proposed to meet the future energy performance regulations, taking into account the lower insulation quality of straw bales and the higher risk for summer overheating in these lightweight houses.