Experience of Upgrading Existing Windows with VIG

Abstract

Existing windows are often equipped with IGU (Insulation Glass Units) glazing of low thermal performance. A change of several decades old IGU glazing with an up-to-date triple IGU is often not possible due to geometry (thickness) or restricted load carrying capacity of existing window frames and its hardware. Using VIG (Vacuum Insulation Glazing) with thickness and weight comparable or even less to "old" IGU can overcome these obstacles. Within a scientific campaign several decades old standard IGU was replaced by VIG in an office building. The paper shows aspects of workmanship in changing glazing (different detailing is needed for bedding of edges e.g.) and presents first measurement data on the thermal performance. Optical effects due to new type of glass – especially the “pillars” to prevent contact due to pressure difference of environment and vacuum – are discussed: these visible effects strongly depend on local view and might irritate customers. At special climatic situations, fogging with polka dots can appear in the morning.