Impact of switchable roof insulation on energy performance of US residential buildings

In the analysis described in this paper, the energy efficiency benefits of switchable insulation systems (SIS) are evaluated when applied to roofs for US residential buildings. Unlike conventional static insulations, SISs can change their thermal properties based on control strategies to achieve desired objectives. In this analysis, SISs applied to roofs are controlled to minimize heating and cooling thermal loads for US housing units. Specifically, 2-step controls are utilized to switch the R-value of SISs between low and high levels depending on outdoor and indoor thermal interactions in order to reduce heating and cooling needs while maintaining thermal comfort within a prototypical one-story home located in different US climates. The analysis results indicate that SISs can significantly reduce energy consumption for heating and cooling systems. The energy efficiency effectiveness of SISs is found to increase for high reflective roofs and for high difference between the high and low R-values especially to reduce cooling energy needs for mild and heating dominated climates. In particular, the deployment of 2-step control strategies operating SISs can reduce annual energy use by up to 44% for space cooling and up to 17% for space heating.