Elevating low-emissivity film for lower thermal transmittance

Researchers from the University of California used greenTEG’s gSKIN®-XI Heat Flux Sensor to investigate the thermal properties of a simple and cost-efficient installation approach of low-emissivity (low-e) films on windows.

Low e-films can be used to retrofit windows in order to substantially decrease energy losses. The new installation approach elevates the film from the glass pane by attaching it to a polymer substrate which is then mounted on the glass pane using frame bars. This creates a 3-5 mm air gap between the window pane and the low-e film.

The gSKIN®-XI Heat Flux Sensor was directly attached to the glass pane, facing the outer side. The heat flux measurements were used to calculate the U-value for this elevated low-e assembly (ELEA) window. The U-value of the retrofitted window was almost 50% lower compared to a single glass window.

Retrofitting windows with ELEA increases the insulation properties substantially. It is a flexible and resilient measure with satisfactory optical properties.

The research has been published in Energy and Buildings:
https://www.sciencedirect.com/science/article/pii/S0378778818336004