Argon gas is a colorless, odorless and harmful gas that has a larger and heavier molecule than air. In fact, is about 51/2 times more dense than air. As a result it takes much longer for Argon gas to transfer heat or cold from the outside glass to the inside surface. Because less energy is transferred, the insulating value significantly improved. The result is less energy energy consumed to heat or cool your home. Another advantage of Argon is sound reduction from the outside for a more quiet living environment.