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Traditional building envelopes have passive insulation systems that cannot respond to dynamic changes in the environment. An Active Insulation System (AIS) consists of Active Insulation Materials (AIMs) that dynamically vary the thermal conductivity of the insulation system. Several researchers have evaluated the impact of AIS on building thermal and energy performance by using simulation tools. Up to 70% savings in annual heating and cooling energy and significant reductions in peak demand have been predicted for some climates with wall systems employing AIS. However, materials and assembly development still need a cost-effective product that achieves the required performance. In this study, we present the process of developing an AIS that we will install in a test hut for its performance evaluation. Minimum performance criteria of the AIS system are developed based on R-low/R-high ratio, required time and efficiency to switch states, and cost estimates. The following steps during this study are creating the concept to meet the requirements, predicting the performance via simulations, developing the experimental setup for bench-scale testing, and finally, constructing a full-scale wall assembly and monitoring the performance when exposed to environmental chamber tests. The selected approach uses off-the-shelf products to create an AIS that can switch R-value between 0.98 ft2·°F·h/BTU (0.173 m2·K/W) and 5.81 ft2·°F·h/BTU (1.02 m2·K/W) and have a switching time of less than one minute between R-high and R-low. [ABSTRACT FROM AUTHOR]

Energy efficiency and hygrothermal performance are some of the main considerations that need to be taken into account during designing and construction of attic roof system. A number of studies have been conducted on building durable and energy efficient attic roofs over the past nine decades. Most of these studies recommend ventilating an attic space as an ideal solution to avoid mould growth and to reduce heating/cooling load of the system. Others studies strongly argued that not every attic space necessarily needs ventilation. This paper reviews the existing body of knowledge on the moisture and energy performances of both practices in different climatic regions. In addition, the effects of insulation, radiant and vapour barriers on both energy savings and moisture contents in the attic structure are revisited. Finally, the emerging technologies which have been recently introduced to enhance the performance of an attic roof are discussed. [ABSTRACT FROM AUTHOR]