The Invisible Insulator by Jon Murphy, Thermal Windows, Inc.

If you do any research on windows or talk to anyone in the window business, you’ll hear about argon gas. Here’s what it is, what it does, and why it is an important part of energy-efficient windows and doors.

Discovered in 1894, argon is a chemically inert element that is colorless, odorless and non-toxic. It is not found in any compounds, but it does make up about 1.25% of Earth’s atmosphere. Argon is produced through liquid air fractionation. In this process, air is passed though a supercooled tube where oxygen condenses out, leaving argon to be isolated and extracted. World production is about 750.000 tons per year. Being the third most prevalent gas in the atmosphere, the supply of argon is virtually inexhaustible.

Argon gas does not harm the environment. It does no harm to the ozone layer and is not a marine pollutant. It has no effect on plants, animals or aquatic life. It is harmless to humans unless inhaled in high concentrations, leading to dizziness and nausea. However, in its liquid form (at -130 degrees F) it can quickly cause frostbite.

The properties of argon have led to many practical applications. It does not react with the filament in a lightbulb even under high temperatures, so it is often used in lighting and arc welding. Some SCUBA divers use argon to inflate their drysuit, taking advantage of its insulating properties. By far the most common use is to fill the gap between panes of glass in windows and doors.

Argon gas is denser than air. Adding it to the airspace in double-paned glass units improves thermal insulation by reducing heat-transferring air currents (“convection”). It is usually used in conjunction with a low-E glass coating. The gas and the coating work together to keep the temperature of the interior glass closer to room temperature, the key to reducing or eliminating condensation.

Adding argon gas to a window costs just a few dollars, yet the gain in comfort and energy efficiency is quite valuable. If you’re considering windows for replacement or new construction, remember that argon gas is a worthwhile investment.

Jon Murphy is a manufacturer’s Rep  for Thermal Windows, Inc., a nationally recognized manufacturer of custom windows and doors. For more information, call (918) 663-7580, go to or visit the showroom and manufacturing plant at 31st & 129th East Avenue in Tulsa. Factory tours are available.