Argon-Filled Windows
 

Illinois has mandated that all new windows sold in the state be argon-filled. This pisses me off because it has now set in stone one specific technology, and if a better one comes along, we won't be able to use it. :rolleyes:

That said, what is the logic behind argon-filled windows. I would think a vacuum would be even better as it would prevent heat from conducting outside the house in winter. If a dense gas like argon is preferable, why not sulfur hexafluoride instead?

That said, what is the logic behind argon-filled windows

In theory, it would be more effective at preventing heat transfer; in practice it's making someone wealthy.

So it is more effective at wealth transfer?

Nitrogen would make more sense IMO.

a vacuum would indeed insulate better. I would assume they don't use it for practical reasons. Glass widows have very large areas so the glass would have to be very thick/strong support the loads. Imagine a 3x6 ft window with a near full vacuum would have to support 18 Tons of force whitin the glass.

I imagine argon is used because it is inert, relatively light, and cheap. Lighter should be better, but easier for the molecules to escape

Benefits of Argon Gas Windows

Argon is the gas most often used between panes in a double- or triple-glazed window. The gas is colorless and odorless, says Bill Lingnell, head of Lingnell Consulting Services in Rockwall, Texas, an independent consultant who works with the Insulating Glass Manufacturers Alliance (IGMA). Argon is denser than the atmosphere, providing more thermal efficiency than having air between the panes, he explains.
Other Types of Gases

Krypton gas is denser than argon, and xenon gas is denser than krypton, providing somewhat more thermal efficiency. Some manufacturers also may offer a mixture of two gases. But the incremental benefit of these higher densities doesn’t necessarily justify their prices, says Carroll Bogard, manager of Trade Segment Marketing for Pella Windows in Pella, Iowa. “Dollar for dollar, argon gas does the best job,” he says.
What Do Filled Windows Offer?

Added energy efficiency is the key benefit to having gas-filled windows, Bogard says. The gas acts as an insulator, working in both summer and winter to keep interiors protected from outside temperatures. Typically, gas infusion is provided in conjunction with applying a low-emissivity (low-E) coating film to the glass panes, he notes.

interesting. I need to think about this for a while. It goes against my intuition that the conductivity of gas would decrease with increasing density. This snipit give an explanation, which is still counter intuitive to me.

Ironically i have a degree in heat transfer. I should have paid better attention apparently.

https://www.electronics-cooling.com/1998/09/the-thermal-conductivity-of-gases/

I think Argon blocks certain wavelengths of light. --that other mode of heat transfer. ;-)

I have low-E, argon filled windows in my home. I think they do a pretty good job, but I've been told the argon leaks out from between the panes over time. The windows have two formed panes fused together to make one unit.

Maybe, but a quick google didn't turn up any supporting data for me. Windows are transparent in the visible spectra (duh), are supposedly treated by "low-e" coatings for infrared and UV reflectivity.

I would be interested in seeing differences in absorptivity/reflectivity for argon vs air. I suspect it is a high order effect, but not sure.

All windows sold in the stare, not all windows installed in the state.

You could just buy elsewhere.

There ya go...

Here is a great article on it all.

Understanding Energy-Efficient Windows - FineHomeBuilding

Apparently, when the windows leak the argon, not much changes.

Q&A: Is it a worth the extra cost to buy windows filled with argon gas?

Early in my career, I sold argon. Then I sold aluminum. Both times to window manufacturers. I always heard it was a bit of snake oil. Gas leaks out. Argon is a larger molecule than nitrogen.

I've got 40 years in the custom artglass business and have ran insulated units
as part of many projects. Sales people like to sell the argon as an upcharge.
The guys in the shop that I know who actually run the units don't think it lasts
more than 6 months. Stick with Low e which has a proven track record of actually
doing something. When you convert the u- value of a window to r- value as in the
consumer report article, the added argon is inconsequential over a regular insulated
glass unit with a low e coating. Most of your heat loss is straight up through the
ceiling anyway.

That's nice, but the state of Illinois has mandated that I buy argon.

I agree it should not be mandated.

I'm guessing one of Madigans friends owns an Argon plant...

that statement is specifically about conduction/convection in the article. It doesnt say anything about radiation blocking properties of argon which was the original supposition. It does give a great explanation of how radiation is blocked/transmitted by (low e) coatings

Fill them with helium and have self opening windows.