The U value, a measure of thermal transmittance, is remarkably low in vacuum glazing, indicating its effectiveness in minimizing heat transfer. The Exact U-value number of Vacuum Glazing is from 0.4 to 1.0 depending on the performance of the VIG and the technology applied by different vacuum glazing manufacturers. For instance, products like LandVac Tempered Vacuum Glazing boast a U value of 0.4, outperforming traditional triple glazing which typically has a U value of 0.8.