Low-Emissivity / Solar-Control Glass Calculator

Transparent in the Visible, Reflective in the Infrared

A low-E coating puts an ultrathin silver layer between two ZnO dielectric layers on glass. The silver is thin enough to stay transparent across the visible band, yet it strongly reflects near-infrared and thermal radiation — letting daylight in while rejecting radiant heat.

Why Thin Silver Works

Below about 15 nm a continuous silver film transmits much of the visible spectrum, but its free electrons still reflect longer wavelengths, giving low thermal emissivity. The ZnO layers act as quarter-wave anti-reflection coatings for the silver, cancelling its visible reflection and pushing visible transmittance back up.

Thicker silver raises near-infrared reflectance (lower emissivity) but eventually darkens the visible. The dielectric thickness tunes the visible anti-reflection — adjust both to keep T_vis high while maximizing heat rejection.

Interactive design tool

This page includes a live transfer-matrix calculator for this design. Adjust the parameters to recompute spectra, layer stack, and performance figures in the browser, then open the design in the full calculator.