Four Season's uses a dual-silver softcoat LowE coating. I believe that your salesman was incorrect when he said it was on the #3 surface...I believe that 4-Seasons' coating is on the #2 surface (inner side of the outer lite)...but while U factor is not affected by the surface the coating is applied to, overall thermal performance can be affected by which surface has the LowE coating.

Argon is about a 30% lower thermal conductivity than does air. This translates into about a 16% energy improvement in a standard LowE^2 IGU at better than 90% fill. If you have an IGU with a 50% fill, for example, the U factor improvement will be 8% and at 75% fill the improvement will be 12%...you might note the straight line progression on u value improvement based on the amount of argon fill.

The air we breathe is 1% argon. If the IGU is filled to anything over that level, then the argon in the IGU wants to reach equalibrium with the 1% in the atmosphere. The job of the IGU manufacturer is to ensure that the argon in the IGU stays in the IGU. A 1% per year loss of argon due to natural dissipation thru the IGU edge seal (not resulting from a failed seal) is about the best that is currently available to modern technology. This is readily achieveable and is becoming something of the industry standard.

Hope this helps a bit.

I just purchased new windows with argon gas. If the gas were to leak over a period of time.....how would I know it? I have a full replacement guarentee for life....but how would I know if the gas leaked out?

Hi.
My question, how we can check, the argon in between,or not. Some salesperson do not know, because nobody asking this stupid question. Finally one told me, if I hold the lighter front of window, I see 3 reflected light, if gas in it. If I see only 2 reflected light, nothing in. I do not believe it, because I tested old and my new window,all the same.

The average homeowner and sales person won't be able to tell.

Special gas detection equipment has to be used to indicate if there could be an argon gas leak.

Verifying the gas contents of a new window is out of reach for the consumer.

Having said that, one day in the future, transparent aerogel windows will negate the need for inert gas filling.

We are still quite a few years away from aerogel but that advancement is exciting.

I think we will see R-10 windows in very common distribution in the next 5-10 years.

I used to work for a window company. And we all used to giggle when people ordered grid work and Argon gas. The way we got the grid work to stay in was to punch holes in the spacer between the glass and fit the grid into it, locking the grids between the double glass pieces. Yes, we sealed up the holes, but nothing works better than to have not punch the hole in the first place.

Unless the technology has changed, the best bet if going with argon is to NOT have grid in your windows. Grid is a throwback from the past where it was a pain to replace the glass in a whole window, so breaking it into little panes meant that it was less of a pain. (Pun intended) Why we would laugh is that grid work added to the cost of the windows, the more grid, the more expensive. Also, the argon gas was more money. So, you'd have people paying extra money for special gas, then even MORE money to make it easier for the gas to escape.

I've heard a lot of people say, "The windows don't look right without the grid." I guess it's a matter of choice. Growing up, all the windows had grid, unless they were really tiny, because that's the way it was. With most houses having replaced their windows at least once, I think we're getting used to the idea of no panes in the glass, and unless you personally can't feel comfortable with it, you might as well skip the grid, especially if going with argon gas.