Does Argon Gas Actually Work? The Physics of Low-E Coatings
Too Long; Didn't Read
- What is it?: A clear, non-toxic gas that is heavier than air.
- How it works: It moves slower than air, slowing down the transfer of heat (convection).
- The Boost: It improves the U-Factor by about 10-15%.
- Does it leak?: Yes, about 1% per year. But it lasts 20+ years.
Answer First: Yes, Argon works. It is standard in 99% of windows sold in Canada today. If a salesperson asks if you want to "Upgrade" to Argon for extra money, they are ripping you off. It should be included in the base price.
The Science of Sluggish Gas
Heat moves through windows in three ways:
- Radiation (Sunlight) -> Stopped by Low-E Coating.
- Conduction (Touch) -> Stopped by Warm Edge Spacers.
- Convection (Air Movement) -> Stopped by Argon.
Regular air molecules are hyperactive. They bounce effectively between the cold outer pane and warm inner pane, shuttling heat out of your house. Argon molecules are big, fat, and lazy. They don't move as fast. It's like trying to run through water vs. running through air. This slows down the convective loop inside the glass unit.
Krypton: The Expensive Cousin
You might hear about Krypton Gas.
- Argon: Optimal for 1/2" air spaces (Standard Double Pane). Cheap.
- Krypton: Optimal for 1/4" air spaces (Triple Pane). Expensive.
Unless you are buying a specialized ultra-thin triple pane unit, Argon is the correct gas.
The Leakage Myth
"Doesn't it all leak out in 5 years?" No. Modern Insulated Glass Units (IGUs) are double-sealed with Polyisobutylene (PIB) and Silicone. The industry standard allows for 1% leakage per year.
- Year 1: 95% Argon
- Year 20: 75% Argon
Even at 75%, it is still far better than plain air. By the time the gas is gone, the seal itself will likely have failed (foggy glass), which is the real end-of-life for a window.
Summary
Don't pay extra for it (it should be free/included). Don't worry about it leaking. It's invisible insulation that pays for itself in one winter.
Foggy Glass?
If your window is foggy, the seal broke and the Argon is gone. We can replace just the glass unit (IGU) without ripping out the frame.