Low-E glass is a type of insulating glass which increases the energy efficiency of windows by reducing the transfer of heat or cold through the glass. That means in the winter your
house stays warmer; and in the summer it stays cooler. There are two types of Low-E (low emissivity) glass available pyrolytic (hard coat) is considered to be a medium performer, and sputtered (vacuum deposition or soft coat) is considered to be the highest performer.

Argon is a safe, odorless, colorless gas which is heavier than air. When used in conjunction with soft-coat Low-E glass, argon provides better insulation. That's because heat and cold do not pass through argon gas as easily as through air. Argon is non-toxic. Use of argon presents no human health or environmental concerns.