Window Efficiency

[redpoint5]

The door to door salesmen are out in force today. 2 different guys stopped by asking if I wanted a quote on a new roof and windows.

One guy said their windows are filled with krypton gas. I haven't researched this yet, but is this the preferred gas these days? How does the window retain the gas for so many years considering tires leak air all the time.

The spacers/seals on my south-facing windows have cracked and let minor amounts of moisture in, which is visually unpleasant, but I'm wondering how much energy I might be loosing through them? Is the loss of the inert gas significant enough to be concerned? The sales brochure says the spacers they use are made of HPH. No idea what that is, but I'm wondering how it holds up to sunlight over the years?

Anything else I should know about windows?

[cowmeat]

Argon is also heavier than air, I watched a "How It's Made" episode on how they fill them.
They take a small hose and insert it into a hole at the top of the window and slowly fill it so the argon replaces the air, then they cap off the hole.

The new double pane argon filled low-e 2 glass horizontal slider windows I installed recently (I got a great deal on Craigslist from a couple who bought them new but never installed them) definitely make a big difference in heat/noise reduction where I closed in my lanai and made a sun room out of it. It was well worth it to me since I got them cheap and did the installation myself

Will you ever see an ROI on a window investment if you buy new and have them installed? Doubt it, since most people don't stay in their homes long term these days, but it's more comfortable and quieter for sure while you're there, and it's a selling point if you have upgraded them in an older home!

[Stubby79]

Danged if I know what gas they put in these days...but I replaced our windows with double-paned, whatever-gas filled (rated for most of canada, even though we live in a warmer zone) and it cut our heating and cooling costs in half over the single-paned ones the place came with.

Our heat and/or AC used to stay ON the whole time when it was cold or hot, and now it just cycles on for half or less of the time. More than noticeable difference.

[redpoint5]

Does a double-paned window act similar to a single after the gases have escaped?

I'll likely be moving in about 3 months and renting the house out, so maybe I shouldn't bother. I can buy new balancers for the ones that have broken.

What I really need is a new roof. I was going to do it myself, but don't have time anymore.

[jjackstone]

I asked a window salesman how long the gas would last before full leakage a few years back just to see if he would be honest. Much to my surprise he told me that they are generally good for 5 to 8 years. I expected him to say the gas would never leak out. Regardless, even without the gas, two panes should still be better than one since a small air buffer is still being provided.
JJ

[oil pan 4]

I have air filled windows.
I would like to develop a way to argon fill and refresh them.
Since I already have argon for welding.

I highly doubt that there areally any Windows filled with krypton. It cost at least $700 for a 330 cubic foot bottle.
A 330 cubit foot bottle of argon should be less than $100. Bulk refrigerated liquid argon would be cheaper even per unit.

[redpoint5]

Well the first round of salesmen are finally gone. I figured they would stake some measurements, type out a quote, and email it to me. They took way longer than I expected; 2.5hrs.

Do I want low-E windows in my climate? I enjoy not having to run heat in the spring and fall due to solar heat gain, but does low-E also retain heat better in the winter? Can I still get solar heat gain with the visible light, or is solar heat gained mostly through infrared?

The guy said there are only a few companies that offer Krypton filled windows. Don't know that I'd want to pay extra if it only keeps for 5 years.

Not only that, but I'm only replacing the south facing windows. I would think the extra insulative value would be compromised by the existing north facing windows, which have probably lost any gas they were filled with.


EDIT: Just found this...

According by "Understanding Energy-Efficient Windows," a Fine Homebuilding article by Paul Fisette, "Argon and krypton are safe, inert gases, and they will leak from the window over time. Studies suggest a 10% loss over the course of 20 years, but that will reduce the U-factor of the unit by only a few percent." The seals used in insulated glazing units are improving all the time. According to the new European standard (EN1279), argon leakage rates must be no more than 0.5% to 1% per year.

[oil pan 4]

Lower emissivity slows down heat transfer.

[Magician]

I have double paned windows...17 years old and climbing.. not gas filled. Seem to work pretty well... especially since I installed solar tint on the outside panes. Wow... what a difference and they say the solar film blocks heat better than any window made. 70% of the solar heat is blocked and 99% of the UV rays. I spent under $500.00 installing the film myself and it looks fantastic. BTW, if you're not a person that is fairly handy and doesn't pay attention to detail, then don't try to install yourself. Precision is key. In window tint...cleanliness is Godliness.

[freebeard]

Does a double-paned window act similar to a single after the gases have escaped?

You're trading conduction for conduction->convection->conduction so there would still be benefit. Low-E glass will pass visible light, but block lower frequency re-radiation.

What I really need is a new roof.

I'd like to build something just to put a roof on it, now. The roofing of choice would be the non-solar Tesla roofing tiles. They cost twice as much as asphalt per sq. ft., but less than metal or clay tiles; and will outlast whatever you put them on.