I bought some NOS double glazed aluminum single hung sash for my own house. They were stored outside for some time and looked fine on carefull inspection when I bought them. Once installed in my finished home in December in PA, they started to fog up between the sheets.
40 years experience with some unconventional double glazing suggests that the fix might be to drill a couple of small holes in the sheltered top edge of the outer lights to vent the moisture.
Anybody ever try it? Thoughts?
Replies
This has been discussed before on Breaktime. If you have moisture between the two pieces of glass in an insulated unit then that is a seal failure. The ONLY cure is to replace the insulated glass unit. It's not difficult to replace.....and really not that expensive if you do it yourself.
jocobe
"only cure"
Tempered glass doors don't etch with the 'fog' as readily as plain windows, and you can successfully remove one pane off the separator with heat gun and thin knife, then cleaned, resealed with silicone or butyl while blowing DRY air across the assembly. A little dessicant does not hurt either, original windows seldom use a dessicant.
Did first one like this 20 years ago, still clear - has lasted twice as long as the original seal.
Plain glass another story, have tried, only about 50% success rate separateing panes without cracking, then 90% of the time the glass is etched, due to an enzyme produced acid, not just fogged. You could probably repolish the pane, but at much greater cost than replacement. Some of the repalcement I do on own house are to forget about the insulated glass and just go with 200 YO storm window technology; which, IMHO, is better.
I thought the window was filled with an inert gass.
Mike
AFAIK, a recent trend.
I've been told by a window guy inert gas used to be a dollar upgrade - but they cost the same now.
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I've been told by a window guy inert gas used to be a dollar upgrade - but they cost the same now.
Bob, you are funny. They raised the price of the standard grade (air filled) to the same as argon-filled. :0)
then 90% of the time the glass is etched, due to an enzyme produced acid, not just fogged.
Junkhound, sounds like you know something here. Last year there was a lengthy discussion here about what caused the etching and nobody came up with a satisfactory answer. So what's your take?
You must admitt that you are an uncommon person though, with uncommon skills. The average person is better off replacing the unit, no?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
you bet, same conclusion, unless you are in it just to learn something which is probably worth more than the windows; then
REPLACE THEM -- PERIOD , about $100 for a 3 ft by 4 ft pane retail. Yeah, I know, about cheaper to buy a whole new window.
That said, the only reason 'me' "an expert" on the subject was that a number of years back this question was my first post on this board. First response was from Gabe " you cheap ($$#*&#@@!), just replace them"., or something to that effect. Best compliment in a while, don't know anybody as cheap so always take that as a compliment.
Hey Gabe, you have really mellowed over the years.
Years later, I have still not have determined from any definitive source on the name of the enzyme, etc, so figure no one has done the needed research, which would be costly for the same answer.
There are 2 different acid producing enzymes at work apparently, one results in a streaky type of fog that feels to the touch like heated and cooled wax paper, the other a pebbly type etching like a very fine basketball surface.
Now, if I could just afford a $30K gas chromatograph or a good excuse to put a sample in the one at work, I'd know a lot more.
There have been spacecraft failures for similar subtle reasons, maybe next time access to GCG?
I've always recognized you as one of those mellow unsung geniuses who, if given free reign, could solve the worlds problems and guide us into the twentyfifth century if you weren't so "cheap"
LOL
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
REPLACE THEM -- PERIOD , about $100 for a 3 ft by 4 ft pane retail. Yeah, I know, about cheaper to buy a whole new window.
I too am disgusted by my leaky thermal panes but are you ignoring the low e coating benefits? That's not something I want to live without.
This is an issue I've been cogitating for awhile. No answer. PAHS Designer/Builder- Bury it!
low e coating benefits ?
Good point for those who use cooling a lot to remember.
Where we are in PNW under trees, e-coatings would actually INCREASE my yearly fuel bill by reducing solar gain during all those sunny summer 60 F days. I have not run my heat pump in the cooling mode for 3 or 4 years. There was a mini-fest at Jim B's in August a few years back and Bob posted some pix - some respondents wanted to know where it was since everybody was wearing a light coat!!
Where we are in PNW under trees, e-coatings would actually INCREASE my yearly fuel bill by reducing solar gain during all those sunny summer 60 F days.
I'm apparently missing something. According to my glass chart, using low e coatings drops solar transmittance from 74% to 60%. But it also drops the U value from .49 to .35. I was under the impression that the lower U value more than offset the lower solar gain, particularly as it works 24 hrs/day, as opposed the the relatively short time of solar gain. No?
Or maybe you use thermal shutters? Clearly the best method is single glazed, to get 85% solar transmittance, coupled with effective shutters to give far beyond low e's 2.86 R value. We don't want to bother with shutters and have summer shading to help out the low e coating, which keeps us cooler. No AC needed here either, but that's very unusual for Virginia, a result of PAHS.
The other factor, even more important for us in the sun belt, is the protection for materials from UV degradation, going from 58% to 44% with low e.
PAHS Designer/Builder- Bury it!
Wow! You guys are a lot more lively than the old motorcycle forum. I haven't had this much fun on the web in months.
Alan (posted original question)
Wow! You guys are a lot more lively than the old motorcycle forum. I haven't had this much fun on the web in months.
Hi Alan,
We digress a lot. At least this time it was still about thermal windows. There's a great deal of information exchanged here. I'm really interested in what Junkhound has to say. As I said, I've had/have the same problem and don't have a solution. You notice wain weighed in too, along the same lines. Hope he picks up on my low e question.
That's probably 4 of us, including you, who don't buy the "go out and get new glass" program. Sticks in my craw. My glass is also so large it's a pain to replace. Every 5-10 yrs? I don't think so.
Sorry to hear your motorcycle group was so placid. What happened to the hellraisers? (Another digression <g>)PAHS Designer/Builder- Bury it!
two problems
1. the energy saving wizards in magazines push double windows but never calculate in the cost of replacing fogged windows. you save energy, maybe not money
2. no national standard on how to put them together to have a good seal.
never seen any research on how its done (best way) either.
3. most panes are not labelled as to who made them, no accountability
drops the U value
True for Minnesota where it gets to minus F or Florida or AZ where it gets to 100F+ with lots of sunshine when you need to cool.
e coatings get their apparent "r" value gain (there is negligible "R" value inherent in an e coating, it is calculated and infered equivalence) based on a set of assumptions as to the indoor and outdoor temperatures. Radiation losses are relative to the absolute temperature difference to the 4th power. I lost the spreadsheet ran a few years back or I'd post it (also lost a big Heat pump trade spreadsheet when a hard drive was lost) Anyway, say in Seattle area the average nightime outdoor winter temp is 48 F (282K), while it is 5 F (258K) in St Paul (I'm guessing at St Paul, too lazy to look it up right now). Thus the radiation loss from a 70F (294K) indoor temp in PNW is (258/294)^4/(282/294)^4 = 70% that in St Paul, etc. The nightime has to be traded against daytime direct and indirect insolation from either clear or cloudy sky, etc. It gets to be quite a bunch of calculations. (PS the heat pump trade showed that a 10 SEER unit was actually better than a 12 SEER when operated only in the heat pump mode with the compressor and high pressure lines insulated.) - moral, you cannot trust generalities on commercial rating, you need to determine your specific situation.
Your assumptions are correct in that there are only a few places where e coatings actually cost you on your heating bill (probably saves everywhere where cooling is needed). I did see a published report that Sacremento CA was a place where e coatings lost so much in solar gain during the winter that it was not made up in the summer, but cannot find that reference right now .
Thank you. I knew there was something potentially wrong with the generalizations, but hadn't caught on to what it was.
That was a spreadsheet I'd be curious to see.PAHS Designer/Builder- Bury it!
Now, if I could just afford a $30K gas chromatograph or a good excuse to put a sample in the one at work, I'd know a lot more.
Shoot at some one through it..then the CSI team will examine every little bit, and tell ya where the sand came from and how it was melted into the glass, and what you had for lunch on Dec.14th 1962..
And don't forget they'll want a toe jam sample for comparison with belly button lint from all family members !!!
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You have lost the seal. Drilling a hole will not let enough moisture in and out to make a difference.
Replace the glass.
Hey, thanks for all the input.
Guess I'll start drilling and see what happens. I'll post the results here.
Alan
Glad to see you are going to try a 'fix', your result should add to the knowledge base.
One suggestion on a drilling try - RTV a small tube to the 'seal'--if you have vacuu pump or old AC compressor you can use as one, pull some vacuum on a hot day and RTV seal the hole after you have had the vacuum on for a few hours, should get good results if the vacuum does not break the window.
If nothing else, it will be an educational experience with nothing to lose.
Let us know the results, if you are able.
;o)
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I think someone on a past thread indicated they had purged the gas from between the two panes by drilling two holes and forcing a dry gas under pressure into one of the holes. I don't recall what type of gas was recommended, but I have thought about trying it with some of the argon used for welding.
You guys crack me up.........are you trying to repair this for fun, 'cause there's no way this is cheaper then replacing the glass....
Tried that. Didn't work. The manufacturer ended up resealing the unit.
Hey, finally someone who tried it. Please be more specific about exactly what you did. E.G., panel size, howmany, where, how big?
It was a 4x4 (two 2x4 thermopanes) shop built skylight on a 5/12 roof. On the eave side an aluminum angle acted as a stop and neoprene blocks separated the angle from the glass.
After about three years one of the units started to fog and at times you could see droplets running down inside the unit. Thinking that I had got nothing to lose, I drilled two 1/4" holes through the angle and the aluminum spacer, one at each corner on the eave side. Tried to use a straw adapted to a hair drier to dry it out but didn't make much progress. After a few sunny days it finally dried out but you could still see the streak marks from the water.
Sealed the holes with silicone and caulk around the skylight the best I could, only good till the first rainfall.
The problem I see with this method is you are still left with the problem of a broken seal so it won't be too long before it fogs up again.