15th Canadian Conference on Building Science and Technology, 6-8 November, 2017, Vancouver, BC, Canada
field study; thermal response; hygorthermal; response; highly insulated; wood-frame walls
A key component of energy efficient homes in the ever challenging climate of Canada is the highly insulated and well-designed wall assembly. Over the years, residential walls have been constructed using increasingly more insulation. The increased levels of insulation have offered a major opportunity to reduce heat losses in homes thereby significantly improving their energy efficiency and have thus permitted compliance with requirements for high performance housing standards such as those for ENERGY STAR, R-2000, Net-Zero Energy Ready homes and homes conforming to the Passive House Canada concept. However given the use of higher insulation levels, homebuilders face many challenges with the issues that arise from changes in traditional construction practice, in the case of this paper being concerned with the overall moisture performance, and hence durability, of wall assemblies. Canadian building code authorities also require proven evidence that highly insulated wall systems will not be adversely affected by increases to insulation levels given the many different Canadian climates in which they are expected to perform over the long term. Building code authorities are also concerned with the possible effects of climate change on building design, and consequently, there is a growing need for information related to the resilience of wall assemblies for use in high performance housing and small buildings. Several studies have been undertaken in recent years to demonstrate the thermal and hygrothermal performance of highly insulated wood frame wall assemblies and to determine whether these walls perform as well as or better than NECB compliant walls when subjected to Canadian climate extremes.