Glass plays a vital role in the design, functionality, and aesthetics of any building, whether residential or commercial. As glass technology continues to advance—improving solar, thermal, and acoustic performance—it’s essential to consider its impact on building connectivity.

Three Critical Glass Factors That Influence Building Connectivity

1. Glass Coatings

Sustainable building standards like LEED, BREEAM, and the EU’s Nearly Zero-Energy Buildings (NZEB) directive have driven innovation in glass coatings. These coatings significantly enhance energy efficiency and help reduce global warming by improving a building’s thermal insulation. Today, virtually all glazing on the market is coated, regardless of the supplier, as it’s the only way to meet modern high-performance energy standards. For example, uncoated double glazing typically has a thermal U-value of 3.0, while coated glass can lower this to a U-value of 1.0, offering much better performance.

However, while these coatings boost insulation, they also present a challenge: they can hinder the propagation of wireless signals inside buildings—a concern as coated glass becomes more widespread.

Glass coatings consist of extremely thin, nearly invisible layers of metal oxides (such as zinc, tin, and silver) that improve insulation and block solar radiation. These coatings are applied via an electromagnetic vacuum process and, while highly effective, are sensitive to humidity. This is why they are always placed inside the cavity of double or triple glazing units.

There are two main types of glass coatings:

• Low Emissivity (Low-E) Coatings: Designed to reflect infrared radiation emitted by heating systems inside a building, while allowing solar heat to pass through from the outside, keeping interiors warmer during winter. Low-E coatings are mostly used in residential buildings.
• Solar Control Coatings: These block more of the infrared spectrum and are optimized for balancing thermal comfort, light transmission, and aesthetic appeal, maintaining optimal indoor temperature and clarity. These coatings are common in commercial buildings with large glass facades.

While effective at their intended purposes, both coating types significantly reduce the strength of radio signals, which are already weakened by propagation from base stations and by physical obstacles. Coated windows can cause an additional 20-40 dB reduction in signal strength compared to uncoated windows. From a wireless communication standpoint, this signal loss is considerable and can lead to poor connectivity and degraded services inside buildings.