Thermo-economic analysis of building energy retrofits using VIP - Vacuum Insulation Panels

Vacuum Insulations Panels (VIPs) are one of the most common Super Insulating Materials (SIMs) on the market today. Although their performances are very high, one of the main drawbacks that limits their widespread application is the high initial cost, which is, on the average, 5 times higher than traditional building insulating materials. The usual approach used to assess the economic feasibility of the energy retrofitting of buildings by means of VIPs takes into consideration the initial cost and the savings due to the reduction in the energy demand. However, it usually results in (unacceptable) long Pay-Back times. In this paper, an energy and economic analysis has been carried out considering the case of the internal insulation wall retrofitting of a typical office building. The Discounted Pay-Back Period (DPBP) has been calculated in order to compare VIPs with expanded polystyrene (EPS). The main advantage of the application of VIPs is an internal space saving as a result of the thinner insulation, but this benefit is frequently not considered in an adequate way. For this reason, the monthly rent has been accounted for in the present study, together with various other variables (climatic zone, aspect ratio, insulation thickness, heating system and ageing effects). The results show that VIPs can be a cost-effective alternative to traditional insulating materials, and they comply with the mandatory requirements related to energy efficiency, when the rental cost is approximately higher than 220 - 320 €/m2 per year (depending on the climatic zone)