What's the difference between Argon and Krypton gas?

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What's the difference between Argon and Krypton gas?

#1 Post by VA-Windows »

In my research and quest for windows, I find that most windows have Argon gas but some come with Krypton. It appears that the Krypton is offered at a premium or on the better / higher line windows. What's the difference? Is Krypton really better?

Second question: How is the gas inserted into the windows? A Schuco dealer made a presentation that indicated that most companies insert the gas through a tiny hole into the window after installation. So, where does the air in the window go? Either the window does not get full of gas or the air escapes. If the air escapes, won't the gas escape too? Does the Schuco method of gas insertion really allow full insertion of gas into the windows in a method will prevent leakage over time?


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#2 Post by VA-Windows »

I just read in anothe post by SoCalWindowMan where a link was provided. I cut and pasted it below:


Posted: Tue Mar 22, 2005 6:46 pm Post subject: Warranty Info
Here are some web sites that list warranty info on different kinds of windows.

What I found interesting in the first link was (go to the bottom of the screen you link into and select the "window" button) the following statement:

"The air space between the 2 panes provides much of the insulation and sound dampening. Argon Gas may be used to fill the space between the glass but most industry experts agree that it is not a good value."

Now, I may be confused (and probably am) or this may be out of context (just for SoCal?) but I thought the gas (either argon or krypton) was a must between the windows and that it significantly improved the insulation and sound dampening. Please help clarify. (Just a note that all the links on this second page were outdated and could not be followed.)

Thanks. VA-Windows

Dean S
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#3 Post by Dean S »

I'm going to speak from memory because I haven't visited this topic for a long time.

Argon gas is a by-product when pure oxygen is separated from air. There are many medical and industrial uses for oxygen and argon is captured and sold for windows. Since it is a by-product it can be sold very cheaply.

Krypton has a slightly better insulation value however it requires a more expensive process to separate it from the air.

Is Krypton better? Yes. Is it worth the extra cost for this slightly better performance? No. I think Krypton is more for marketing than insulation. Companies use Krypton to differentiate themselves from the competition.

When Argon or Krypton is injected I think there is a second hole to suck out the air. There have been other posts on this board regarding fill rates for different companies.

Marvin's glass comes sealed by Cardinal Glass. The two panes are put together and sealed in an Argon filled chamber and there is a 98%+ fill rate.

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#4 Post by JScott »

Dean covered most of the bases without the technical confusion. There are others here who can get you everything you need to know. Here is my free information without quick research.

Krypton is more expensive than argon. Many manufacturers mix the argon with air as the demonstration you saw confirmed. In some situations they will mix air/argon/ and krypton. The krypton is a much better insulator. Our triple pane unit comes standard with argon/air/krypton to achieve a U value of 0.24 and an upgrade to full krypton lowers the value on our window to 0.20

Andersen tested and sold units in the 70's using freon, they called it blue glass. They all failed and caused the green house effect. There is experimentation now with xeon and lord only knows what else. If your in Buffalo NY or above take the krypton. If your a superman fan he probably won't come to visit.

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#5 Post by Oberon »

Argon and krypton are both inert gasses as are helium, neon, xenon, and radon. All of these are naturally occuring and are elements listed on the Period Table while freon, on the other hand, is a chlorofluorocarbon or man-made gas.

Helium is lighter than air while the rest of the inert gasses are heavier than air.
Dry air has a density of 1.29 g/cm^3 at sea level.
Helium at .18 gm/cm^3 and neon at .9 gm/cm^3 are both less dense than air.

Argon at 1.78, krypton at 3.75, xenon at 5.9, and radon at 9.73 gm/cm^3 are all denser than air; but it occurs to me that if a manufacturer brags that he uses radon gas as his window infill he might be risking possible marketing problems so I have my doubts that we will ever see radon as an IGU infill.

Anyway, argon, krypton, and xenon can all be used as an IGU infill with various degrees of success.

The width of the airspace in the IGU has a great deal of influence on the performance of the inert gas versus air.

As a general rule, an IGU with air infill reaches its optimum energy perfomance at about 1/2". This is also close to where an IGU with an argon infill reaches its peak performance. The energy perfomance of the unit will then begin to gradually drop off as the airspace gets wider, no matter if it is filled with air or argon.

An IGU with a xenon infill reaches its peak energy numbers at about 3/16" and then begins to gradually drop off in performance.

An IGU with krypton reaches its peak at about 5/16" and then begins to gradually decline as well.

At 1/2", when argon is at its peak, krypton performance is still slightly better than argon and xenon is still slightly better than krypton. But, the increase in cost will not offset the slight advantage in performance of either krypton or xenon versus argon...so, if the IGU airspace is 7/16" and greater, then argon is the best value. Below that, then it will depend on what the manufacturer is offering.

If you are buying a triple pane or a dual pane with IGU spacing of 1/4" or so then krypton is definitely an option for the greatly improved performance at those spaces. Also at these narrower spacings a mixture of 25% argon to 75% krypton is very close in perfomance to pure krypton at (presumably) a bit less cost.

Curiously, at 7/8", the difference in performance between air and argon is more than is the difference in performance between argon and either krypton or even xenon.

VA, your Schuco dealer was absolutely correct. Many window companies do fill their IGU's like you would fill a bottle with water. They leave a little hole in the top of the IGU and "pour" the gas in since all of the gasses used for insulating value are heavier than air and will displace the air in the unit until it is "full".
As Dean mentioned, some folks will use two holes, one to suck the air out and one to fill the argon.
And some, Cardinal and Schuco immediately come to mind (which is easy since they were mentioned previously), use a sealed vacuum chamber where the air is totally exhausted and replaced by the gas and then the IGU is sealed while still within the chamber.

Hope this all made sense and that it helps a bit!

Window4U (IL)
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#6 Post by Window4U (IL) »

Good post Oberon.

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#7 Post by VA-Windows »

Thank you all for your inputs. It has been very educational and useful. I have been very impressed with all the experts on this discussion board, their willingness to help, and the quality of their information. While nothing more than an interested window buyer myself, I hope some of the posts I have provided are also useful to those shopping for windows.

Thanks again to all the experts who take their time to help us.

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