Hygrothermal performance of a vapor-open envelope for subtropical climate, field test and model validation


The construction industry is known to be a key contributor to manmade climate change. Amongst other nations, Japan has a building energy efficiency goal which does not yet emphasize the importance of the moisture safety design of well-insulated building envelopes considering its diverse climatic conditions. The authors developed a vapor-open wooden building envelope for the subtropical conditions of Japan and optimized a design method, which considers environmental, economic and hygrothermal aspects. As a case study, a detached residential building has been constructed in Ohmihachiman (central Japan). The building has been monitored using a large number of temperature and humidity sensors inside the walls and the roof. Results have been obtained from measurements over a period of one year. Furthermore, transient hygrothermal simulations using the measured exterior and interior climates have been carried out. It was shown that 1) the construction of the wall was successful with the desired level of air-tightness and 2) the simulation model by a commercial software is applicable for predicting the hygrothermal performance of the wall with the envelope system in the actual use condition.

Building and Environment
Yutaka Goto
Yutaka Goto

My transdisciplinary research and education focus on sustainable use of wood in constructions with regards to engineered wood, structural safety, moisture safety, durability, indoor comfort, energy efficiency, resource efficiency, and sustainability impacts.

York Ostermeyer
Chief Strategy Officer and Co-Founder at ChillServices
Holger Wallbaum
Holger Wallbaum
Full Professor, Vice-Head of Department and Vice-Dean for Research

Holger is a Full Professor in sustainable building at the Division of Building Technology, research group Sustainable Building, and in the Area of advance Building Futures. Holger works within sustainable building on concepts, tools and strategies to enhance the sustainability performance of construction materials, building products, buildings as well as entire cities.