Milgard is now making windows in Salt Lake City, and offering argon gas as an option to those of us at 6000′. I have a couple of concerns about the longevity of the gas fill. One competing window rep claims that all windows, regardless of elevation, will lose their gas fill over time because of the small size of the argon or krypton atoms. Is he just blowing hot air at me because he can’t offer me a gas fill window? Is there a general consensus (that’s probably a silly question for this opinionated board) on the value of gas fill, or on it’s longevity?
thanks
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What gets me is that they charge a bunch of bucks for 30 cents worth of argon. They have to flush the air out of the windows with some sort of dry gas, and argon's no more difficult to use than anything else.
As to how fast argon will diffuse out, I'm guessing it's mainly an attribute of the adhesive used to bond the pane together. But I wouldn't think that it's apt to diffuse out that rapidly, since if argon can diffuse out, water can diffuse in (though quite a bit more slowly). And it's not clear how altitude would affect this rate of diffusion one way or another. (If anything, it seems like altitude would reduce diffusion.)
As to the merits of argon, that's another question. It supposedly has less heat capacity and so reduces convective loss through the window. How significant the difference is, I don't know. My guess is that it is swamped by other factors such as the quality of the air seal between sash and frame. Also, at higher altitudes convective losses are reduced anyway, due to the thinner air.
All them puckeys is blowing hot air. If your are going to e in your house over 15 years, IMHO "insulated glass" is a big pile of $hit on the fan.
Go with old fashioned storm windows - been there, done got screwed, etc.=--- should have known better though!@
my sealed unit manufacturer told me that they reckon you lose about 1% of the argon every year
Ar has less thermal conductivity than nitrogen. Part of that is due to its lower heat capacity (it is mono-atomic, not diatomic so it has fewer vibrational and rotation modes to absorb heat). Ar has a shorter mean free path because of the larger moecule size. Helium (which makes you sound like Mickey Mouse) has a longer mean free pass and therefore conducts heat further therefore faster.
So 1) Ar wroks better in a window than N2, no question. Does it 2) stay in window very long? It is mostly a function of how well the window is sealed. But the larger size of the molecule definitely reduceds its difussivity (diffusion rate) relative to a smaller species.
So, yes, it is worth paying for noble gases in your windows. The bigger the better. It is even more worthwhile to pay for well sealed windows in which the seals will last. But that is harder to assesss.
After listening to what people here had to say, and listening to a couple of window salesmen, we decided against the argon fill. I'm still not sure that anyone I talked to really knew what they we're talking about. I finally decided that going triple pane/ low-e was a more reliable way to go. Not looking forward to hoisting those 6'x5' triple panes though.
Does anyone else get a sleazy feeling from window salesmen?
Triple pane clearly helps. And if it leaks its argon, it is still ahead of a leaky double-pane.
Look for unequal spacing to cut sound better. 1/4" through 3/4" is all defensible in terms of heat loss. But a given gap passes certain frequencies better. So different gap spacing cause one to block what the other one passes.
My 6x4 double-panes were big enough for me - the upper ones were at 19 feet up. 6x5 triple? - I'd be tempted to bring in high-reach fork-lift if they are far off the ground.David Thomas Overlooking Cook Inlet in Kenai, Alaska
The unequal spacing sounds like good advice, esp. since hiway noise is an issue. I've got one 6x4 going up high, that'll be tricky, and there's no room for a forklift back there. Sounds like scaffold and a bunch of guys.
I can't say that what the window rep says is true, but it is reasonable. I doubt he would have been smart enough to make it up. Argon and krypton are both monatomic molucules, whereas nitrogen and oxygen are diatomic, and carbon dioxide and water are both triatomic. So argon and kyrpton may be smaller. I don't have the references to check. And they have no electric dipole, so they might leak more freely.
Helium leaks easier than any other gas, because it is the smallest molucule, is monatomic, and has no electric dipole. Helium is used to leak check precision and high vacuum systems.
I have always questioned the concept of argon. I prefer to specify a higher end Low E for my money.
Check with your local utility company. Most times the extra cost in energy effecient windows will not save you what you will spend,compared to the life of the window.
It's like putting a refrigerator on a 30 year mortgage. It's long gone to the scrap yard and you're still paying for it.
where I live the seals blow out and the windows fog.