Long-term in-situ assessment of vacuum insulation panels for integration into roofing systems: Five years of field-performance

•Composite insulation of polyiso and VIPs were monitored and evaluated for five years.•VIP composite outperformed conventional polyiso during the five years of monitoring.•The R-value of the VIP composite was on average twice that of the conventional polyiso.•The long-term performances of the VIPs were within 10% of their initial value. The use of vacuum insulation panels (VIPs) is under investigation by the National Research Council for use as a complementary material for current insulation systems. VIP composites, consisting of VIPs sandwiched between polyiso panels, were constructed and incorporated into a modified bitumen roofing system in Ottawa, Canada. The VIP composite, as well as a conventional polyiso system, were monitored in-situ for a period of five years to observe their performance. It was found that the composite VIP insulation outperformed the conventional polyiso system for all months and years monitored, providing an increased barrier to heat flow, reduced temperature driving forces for energy loss, and R-values that were on average twice that of the conventional polyiso system. The long-term performance was also assessed for the five year period and it was found that the VIP composite performed within a 10% margin of its original value for consecutive years. This study successfully demonstrated the energy saving potential that can be achieved through incorporating VIPs into current roofing and building applications.