These are considered to be the current highest performing windows in the world, with the possible exception of ones with aerogel laminated between the glass. However, aerogel looks a bit smoky and allows less light in. It also is extraordinarily expensive, and is probably not available for residential use.
If you%26#039;re at a high elevation, like at 7-10,000 feet in the mountains, keep in mind that the argon gas will eventually leak out of the seals in double-glazed windows meant for lower elevations and the efficiency will drop as time passes. These windows will only last about 15-20 years before needing replacement in that circumstance.
Or at least that%26#039;s how it was two- three years ago: this problem might have been solved by now. Obviously I haven%26#039;t checked lately. 29% 2 Votes