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daniel nantell
10-17-2009, 06:00 PM
When the seals are beginning to fail and fog is appearing , do most inspectors state that the window is defective and needs replacement or write it up as a deferred maintenance repair that will need to be addressed sometime in the not to distance future. thanks for any info.

Scott Patterson
10-17-2009, 06:21 PM
When the seals are beginning to fail and fog is appearing , do most inspectors state that the window is defective and needs replacement or write it up as a deferred maintenance repair that will need to be addressed sometime in the not to distance future. thanks for any info.

I just say they are fogged and go on with life. If my client wants to replace or have them repaired that is up to them.

Gunnar Alquist
10-17-2009, 06:26 PM
There is no deferred maintenance, they have failed. Generally, replacement is necessary to correct. However, I have heard about a method that does not require replacement of non-tempered windows. Don't know anything about how well it works or if it is available in all areas.

Ted Menelly
10-17-2009, 07:07 PM
There is no deferred maintenance, they have failed. Generally, replacement is necessary to correct. However, I have heard about a method that does not require replacement of non-tempered windows. Don't know anything about how well it works or if it is available in all areas.


I inspected a home for a British couple that owns a business that gets rid of the fog in the window and then seals it. Supposedly it works quite well and is fairly easy to do. I think it is more of a commercial application.

Anyways I write it up a in need of repair. A fogged window is a broken seal in the thermal window and is extremely unsightly and sooner than later you will not be seeing thru the window at all.

It is a failure of a system and needs repair. Funny thing is we can only check a box off stating it is deficient. I still write it up all the time as in need of repair.

Chuck Lambert
10-17-2009, 07:32 PM
There is no deferred maintenance, they have failed. Generally, replacement is necessary to correct. However, I have heard about a method that does not require replacement of non-tempered windows. Don't know anything about how well it works or if it is available in all areas.

There are a few here in So Cal that claim they can FIX fogged windows. Actually what they do is drill two very small holes in them so they can 'breathe' no more fogging and no more seal!!

Jerry Peck
10-17-2009, 07:44 PM
As Gunnar said, the windows have failed.

While the windows may still keep rain out, and (to varying degrees) let you see out through them, the windows are no longer performing their INTENDED function - replacement is the only proper corrective action.

Write them up as deficient or disguise them as maintenance?

- Put it this way:
- - 1) If you write them up as deficient your client gets to negotiate about the windows based on the wording in most real estate contracts, which is, after wall, one of the main reasons the buyer hires a home inspector.
- - 2) If you write them up as maintenance your clients gets to cover the entire cost of replacing those windows, which is not fair to your client nor what you were hired for.

Some inspectors operate under 1) above and are their on their clients behalf, other inspectors operate under 2) above and simply push most things under "maintenance" and provide little real help to the client.

I operated under 1) - EVERYTHING which was not right was deficient and written up, and the contracts covered virtually everything, which gave my clients the ability to negotiate everything I wrote up.

It then become my clients choice to accept, negotiate, or reject based on all those items, without me running interference for the sellers (or agents) by saying (effectively saying) 'Oh, that's just maintenance, you can deal with that later at your own expense.' No, it was either right, or it was not right, and if not right, then it was deficient. Plain and simple.

Matt Fellman
10-17-2009, 10:39 PM
I have a disclaimer in my contract about identifying them. If I do see one and mention it I state there may be additional ones that could not be seen due to the failure being recent or the weather conditions being such that the failure was not visible.

Searching for them is a pain since many windows are dirty and it's tough to tell the minor ones.

Ron Bibler
10-17-2009, 11:17 PM
Window are going to fail at some point. the first sign is in the seal. If you look at most windows you can see areas of the seal lifting up or the caulk is deformed. I make note of this condition in almost every report and inform the buyers that the windows will fail at some point in time next week next month or 3 years down the road. If one is fogging up others are soon to fallow

Best

Ron

Tim Spargo
11-17-2009, 11:04 PM
Verbiage to indicate a likeliness of others to follow/fail as well as limitation such as dirty windows limiting visibility etc.


BTW.. there are a few vendors that repair fogged windows... my understanding is that if the window is not too far gone, good results can be obtained.

Foggy Window Restoration, Moisture Removal, Hard Water Spots and Scratched Window Glass Repair and Replacement (http://www.theglassguru.com)

Defog Foggy Window Condensation for Restore Repair Home Improvement Pane (http://www.defogit.com/)

A.D. Miller
11-18-2009, 04:02 AM
I say that they have come to the end of their service life and recommend that they be repaired (as TS mentioned above) or replaced (in areas with no repair vendors).

A.D. Miller
11-18-2009, 04:21 AM
By the way here are a couple more:

Crystal Clear Window Works (http://www.crystalclearwindowworks.com)

Window Defoggers Repair Foggy Double Pane Condensation Moisture (http://www.wefixfoggywindows.com)

Ken Rowe
11-18-2009, 09:58 AM
If it's only one or two window I'll write them up as maintenance, but still in the summary of my report. If it's more than a couple I'll write them up as action items basically due to the cost.

Tim Spargo
11-18-2009, 11:04 AM
Just food for thought, from experience I've seen that once windows start failing most with East, South and west exposures are going to start failing as well.

The reason I mention this is customers may wish to be aware that if an insulated glass unit is failing, others will likely follow, especially if the house/windows has some "miles" on it... meaning more than 10 years old or so.

Many customers think the dual pane windows are an attribute and this is of only cosmetic concern... Dual pane windows ARE obviously an attribute, but this defect can get expensive and as we all know, the condensation usually doesn't get much better.

Good Luck!

Bob Elliott
11-18-2009, 12:32 PM
Once the seal is broke and the Argon is missing I consider that a need to replace.

Bruce Ramsey
11-18-2009, 12:36 PM
Window contractor attended HI assocation meeting last evening to let us know about his service to "repair" fogged sealed windows. He drills two holes in the interior pane and puts valves over the holes. Now the windows "breath" so no more fogging. Also no more sealed unit. But the seal was already lost since they were fogged.

If the windows are sealed units and the seals faile, the window is damaged and needs replacment since it is no longer functioning as designed. If you drill holes in the window, the seals are still failed and not functioning as designed. They have not been repaired, they have been further damaged. The window contractor did not see it that way.

Now we have one more thing to look for, tiny little valves in opposing corners indicating the seals failed and someone sold the seller a non-existent fix.

Jerry Peck
11-18-2009, 07:33 PM
If it's only one or two window I'll write them up as maintenance, but still in the summary of my report. If it's more than a couple I'll write them up as action items basically due to the cost.


Ken,

Why does "cost" change something from "maintenance" to "repair"?

Either they are bad or they are not, it does not matter if only 1 is bad or if 100 are bad ... they (or it) are still "bad".

I chuckle when I read the title of this thread ... "beginning to fog up" which implies "beginning to fail", which is like "being a little bit pregnant" - yeah, right ... either you are, or you are not, and if you 'are' it does not matter that you 'are not' "showing much", which is like thermal windows 'not' "showing much" fogging up.

:D

chris mcintyre
11-18-2009, 09:40 PM
Once the seal is broke and the Argon is missing I consider that a need to replace.

What if the seal is broken and it didn't have Argon to start with? :)

Tim Spargo
11-18-2009, 09:56 PM
Agreed Jerry,

Cost is never ours to assume tolerable or not in regards to reporting defects.

We may decide something like an outlet or switch cover (unless they're fancy) is a minor item... but some or most of us are likely to mention it.

We may be performing an inspection for someone who is ready to walk at the first sign that a home will need $500 in basic service or maintenance...

You can't really know..

We may be performing an inspection for someone who is planning to do a major overhaul, but they have their own needs in obtaining a report.

It doesn't really matter. "Just the facts Maam, just the facts"

As a matter of fact, what if we let comments like "I'm replacing all the windows pretty soon anyway" affect whether or not we are to note something.... not a good idea.


Take care,

Tim

Bob Elliott
11-18-2009, 10:07 PM
What if the seal is broken and it didn't have Argon to start with? :)

They fill them with Argon gas as far as I have always heard. That's what makes them thermal efficient.

Either way it means replace ,as the repair option is not standard .

If you were buying a place what would you want?

chris mcintyre
11-19-2009, 04:36 AM
They fill them with Argon gas as far as I have always heard. That's what makes them thermal efficient.

Either way it means replace ,as the repair option is not standard .

If you were buying a place what would you want?

That was my point, that all insulated windows are not Argon filled, in fact (at least around here) most are not.

If I was buying the house I would want it replaced, unless it was like the window in the first link that Aaron posted. :)

BTW this is the first I have heard of "defogging" windows, thanks A.D. & T.S.

Rick Cantrell
11-19-2009, 05:23 AM
"which is like "being a little bit pregnant" - yeah, right ... "

I like that.
Now I need just the right opportunity to use it.

James Bohac
11-19-2009, 07:13 AM
I have been a partner in a window defogging business for the last two years.

The term failed seals is a little misleading. All thermal windows have a dessicant material between the two glass panes around the outside egdes of the glass. This dessicant absorbs moisture which enters the inner glass area. When the dessicant gets saturated, the moisture shows up between the glass depending on the Dew point.

Most window manufacturers have engineered the windows to absorb moisture at least through the warranty period of the window, commonly 10 years.

Windows recieving the most amount of direct sunlight usually fail first due to what they call solar pumping caused by heating and cooling the glass. Harsh weather such as driving rain and pressure washing a window can also lead to early failure.

The defogging procedure does prevent the moisture by relieving the pressure between the glass but does slightly reduce the R value of the window. The procedure is only effective on windows showing moisture with no white fogging or mineral deposits. The white stains are etched into the glass and the window would need to be replaced.

A.D. Miller
11-19-2009, 07:26 AM
This is boilerplate in my reports:

Most people do not know it, but the cause of fogging in thermal pane window units is not so much due to a loss of seal, as it is to a failure of desiccant placed within the units to absorb moisture. It is incorrect to think that there is a hermetic seal drawn on these windows. This is an impossibility (nature abhors a vacuum). So then, the seal that is initially accomplished is imperfect and leaks from the very beginning. That's right, they leak straight out of the factory. All of them leak. Thinking that thermal windows are not leaking is just plain mistaken thinking. It’s a bit like thinking that a house in an area with known expansive soils has a stable foundation. Urban construction mythology.

As soon as a thermal pane unit leaves the shop, it is destined for failure. Moisture diffusion into a sealed unit is impossible to avoid and it is continuous. Manufacturers deal with this reality by loading absorption material, or "desiccant" (usually a silica gel or similar material), in the spacer bar construction of every unit. This material has one job - to bond with water molecules. The material comes in the form of beads, similar to those you find accompanying new leather and electronic products, or as a blended compound, often a black butyl or cork-like wafer.

Every insulated glass unit (IGU) has a finite capacity for how much water it can hold ("hide"). Over time, as moisture accumulates, the unit finally reaches a threshold saturation point, it becomes visible as condensation between the panes of glass (this is directly associated to the falling dew point between the panes of glass).

The options available for fogging IGUs are:

(1) Replacement of the thermal panes. This is the most expensive option. Prices vary greatly due to types and shapes of panes. Replacement costs begin at about $75 per small rectangular pane and rise sharply.

(2) Repair of the thermal panes. This option is about half as expensive as replacement. See: Repair Foggy Windows & Condensation Problems Crystal Clear Window Works, et al.

(3) Do nothing about the thermal panes. This is the most frugal option.

James Bohac
11-19-2009, 07:43 AM
AD,
Thats it in a nut shell! I also forgot to mention that Argon filled windows are more of a gimmick to increase the price of the window. Yes argon gas is denser than dry air space and does increase the R-value, however most of the argon has escaped within the first three years after manufactured.

They say in the window biz. " Argon Allgone"

A.D. Miller
11-19-2009, 07:52 AM
AD,
Thats it in a nut shell! I also forgot to mention that Argon filled windows are more of a gimmick to increase the price of the window. Yes argon gas is denser than dry air space and does increase the R-value, however most of the argon has escaped within the first three years after manufactured.

They say in the window biz. " Argon Allgone"

JB: Agreed. The vast majority of windows installed in my area are aluminum- or vinyl-framed nail-on-flange builder units (this means the cheapest thing available that will pass the energy bar). By the time these are beat up during shipment to the distributor, shipment to and storage at the site; and finally wrestled into out-of square openings by semi-skilled laborers, they are lucky to still have whatever seal existed when they were built.

In a hot-humid climate like here, windows on the south and west sides of the house usually go first. The ones on the east are not far behind. Most never make it to the ten year mark. This is doomed technology for cheap products that can easily be sold to stupid Americans for whom bigger (and not higher quality) is better. The same folks who believed in WMD and worship the ground that Caribou Barbie pees on (which is everywhere she goes).:D

Bob Elliott
11-19-2009, 08:59 AM
AD,
Thats it in a nut shell! I also forgot to mention that Argon filled windows are more of a gimmick to increase the price of the window. Yes argon gas is denser than dry air space and does increase the R-value, however most of the argon has escaped within the first three years after manufactured.

They say in the window biz. " Argon Allgone"

I would like to see proof on that as ,if gas is escaping then after 3 years they should all be fogging up.

A.D. Miller
11-19-2009, 09:03 AM
I would like to see proof on that as ,if gas is escaping then after 3 years they should all be fogging up.

BE: The presence or lack of an inert gas such as Argon or Krypton does not account for the buildup of moisture between the panes. This is caused solely by the fact that the desiccant is fully saturated.

James Bohac
11-19-2009, 09:08 AM
Bob,
The window will not fog untill the desicant material in the spaces bar is saturated.

An easy test for a failed seal is to spray canned air upside down on a insulated window. Wipe off the cloud on the ouside of the glass and if a moisture spot is on the inside the seal has failed. The moist air will condense on the cold glass. The desicant is close to saturation and Visible moisture will appear soon inside the window.

Bob Elliott
11-19-2009, 09:30 AM
Bob,
The window will not fog untill the desicant material in the spaces bar is saturated.

An easy test for a failed seal is to spray canned air upside down on a insulated window. Wipe off the cloud on the ouside of the glass and if a moisture spot is on the inside the seal has failed. The moist air will condense on the cold glass. The desicant is close to saturation and Visible moisture will appear soon inside the window.

Ok I will take your word for that but I still feel replace is a good option rather than repair and around here the R value is a bigger issue perhaps as everyone wants to go green.

Must admit I laugh when I see low flow toilets.(we have lake Michigan).

Ken Rowe
11-19-2009, 09:57 AM
Ken,

Why does "cost" change something from "maintenance" to "repair"?

Either they are bad or they are not, it does not matter if only 1 is bad or if 100 are bad ... they (or it) are still "bad".


:D

Most of the time the glass can be replaced without replacing the entire window. Would you seriously tell the buyer that this one piece of glass must be replaced, even though it is not a safety concern and may only be a $40 to $75 repair?

I sure wouldn't. I'd let them know in the report that eventually they may want to do something about it, but would not tell them that it must be repaired.

Now if it was 20 windows or even 2 or 3 of the large windows that will cost $300 each just for the glass, then I'd tell the buyers to get estimates for repairs prior to closing.

Ken Rowe
11-19-2009, 10:05 AM
Agreed Jerry,

Cost is never ours to assume tolerable or not in regards to reporting defects.

We may decide something like an outlet or switch cover (unless they're fancy) is a minor item... but some or most of us are likely to mention it.

We may be performing an inspection for someone who is ready to walk at the first sign that a home will need $500 in basic service or maintenance...

You can't really know..

We may be performing an inspection for someone who is planning to do a major overhaul, but they have their own needs in obtaining a report.

It doesn't really matter. "Just the facts Maam, just the facts"

As a matter of fact, what if we let comments like "I'm replacing all the windows pretty soon anyway" affect whether or not we are to note something.... not a good idea.


Take care,

Tim

I actually talk to my clients at the beginning and during the inspection.

Bob Elliott
11-19-2009, 10:19 AM
Most of the time the glass can be replaced without replacing the entire window. Would you seriously tell the buyer that this one piece of glass must be replaced, even though it is not a safety concern and may only be a $40 to $75 repair?

I sure wouldn't. I'd let them know in the report that eventually they may want to do something about it, but would not tell them that it must be repaired.

Now if it was 20 windows or even 2 or 3 of the large windows that will cost $300 each just for the glass, then I'd tell the buyers to get estimates for repairs prior to closing.

Sorry for any misconception.
I actually only report that a seal is apparently busted and recommend a window contractor examine.

Around here I do lots of high priced Condos in the Million dollar range, so what do you think gets done?

I just look out for my client.

A.D. Miller
11-19-2009, 10:29 AM
Sorry for any misconception.
I actually only report that a seal is apparently busted and recommend a window contractor examine.

Around here I do lots of high priced Condos in the Million dollar range, so what do you think gets done?

I just look out for my client.

BE: In the D/FW area most, if not all, glaziers will not identify "failed seals". They simply ask which windows you want replaced and the replace them, assuming that you pay. So then, deferring to a fenestration specialist or whatever will simply not work here.

Bob Elliott
11-19-2009, 10:44 AM
Bob,
The window will not fog untill the desicant material in the spaces bar is saturated.

An easy test for a failed seal is to spray canned air upside down on a insulated window. Wipe off the cloud on the ouside of the glass and if a moisture spot is on the inside the seal has failed. The moist air will condense on the cold glass. The desicant is close to saturation and Visible moisture will appear soon inside the window.

I will note that tip.

chris mcintyre
11-19-2009, 03:06 PM
Bob,
The window will not fog untill the desicant material in the spaces bar is saturated.

An easy test for a failed seal is to spray canned air upside down on a insulated window. Wipe off the cloud on the ouside of the glass and if a moisture spot is on the inside the seal has failed. The moist air will condense on the cold glass. The desicant is close to saturation and Visible moisture will appear soon inside the window.

I like the concept of this "test", but I'm unclear on this part. Could you elaborate?

Vern Heiler
11-19-2009, 03:15 PM
This is an impossibility (nature abhors a vacuum). So then, the seal that is initially accomplished is imperfect and leaks from the very beginning. That's right, they leak straight out of the factory. All of them leak.

A.D. Your post implies that the windows are shipped with a vacuum drawn on them. If the window has an inert gas in it, such as argon, it does not have a vacuum.


Moisture diffusion into a sealed unit is impossible to avoid and it is continuous.

Really! Then all of the old tube type TV's should be full of water.

I do not believe that all of the IGU's that leave the factory are leaking from day one. I have inspected many insulated units that are well past the ten year warranty. The quality windows don't have the same frequency of the problem as the cheapos.

One thing I have noted is that most of the failures are in the fixed upper sash of single hung windows. I believe this is due to shimming the unit too tight to the framing. The majority of the failures are on the South or West exposure where both the window and framing are subject to more expansion and contraction.

A.D. Miller
11-19-2009, 03:45 PM
A.D. Your post implies that the windows are shipped with a vacuum drawn on them. If the window has an inert gas in it, such as argon, it does not have a vacuum.


VH: Perhaps you would define the removal of the air from the unit prior to the injection of the inert gas as something other than producing a vacuum. I would not.



Really! Then all of the old tube type TV's should be full of water.

VH: Apples and oranges are for salads and monkeys; not for comparisons.


I do not believe that all of the IGU's that leave the factory are leaking from day one.

VH: Believe what you like. If the seals were intended to be permanent, why would the desiccant be placed there? Extra parts?


I have inspected many insulated units that are well past the ten year warranty.

VH: Me too; thousands of them.



The quality windows don't have the same frequency of the problem as the cheapos.


VH: It's a tolerance and quality control issue. The same reason that Mercedes will run longer than a Kia (or JP's old Jaguar);) .



The majority of the failures are on the South or West exposure where both the window and framing are subject to more expansion and contraction.


VH: Yes, and that expansion and contraction eventually loosens the seal at the perimeter of the panes enough to allow for the inert gas to escape and be replaced with moisture-laden air, thus overloading the ability of the desiccant to absorb it.

Bob Elliott
11-19-2009, 04:03 PM
Interesting site that states Argon is lost at a rate of 1% per year on average and there is a vacuum.

Double Pane Windows - Understand how they are made and what they can do (http://www.window-replacement-experts.com/double-pane-windows.html)

A.D. Miller
11-19-2009, 04:08 PM
Interesting site that states Argon is lost at a rate of 1% per year on average and there is a vacuum.

Double Pane Windows - Understand how they are made and what they can do (http://www.window-replacement-experts.com/double-pane-windows.html)

BE: Good post, but beware: You can lead a horse to water, but you can't make him drink, as you can lead a fool to knowledge, but you can't make him think.:D

Vern Heiler
11-19-2009, 04:48 PM
BE: Good post, but beware: You can lead a horse to water, but you can't make him drink, as you can lead a fool to knowledge, but you can't make him think.:D

And sometimes you can't get them to read.....

"If you are worried about the gas escaping after one year and you are left with a regular window, tests show that the windows only lose less than 1% per year of the inert gas. This means after twenty years you will still have 80% of the gas in the window."

" If the window has a gas fill, the gas is injected at this time and the airspace is sealed off. Once this is done the butyl edge is allowed to set and the insulated glass is complete."

The Gas replaces the vacuum.

A.D. Miller
11-20-2009, 08:20 AM
VH: If the shoe fits, wear it.

Vern Heiler
11-20-2009, 10:22 AM
VH: If the shoe fits, wear it.

I believe it's your size!

Bob Elliott
11-20-2009, 10:58 AM
It is the same technique I used when filling Glass tubes with Neon and Argon gas.
The vacuum draws in the gas but a vacuum still remains at the end.

Glass can support a vacuum and there are neon tubes close to 50 years or so still working well.

Some I installed 30 years ago are still going.

(sorry forgot to mention I did neon signs in the eighties)

Roy Cooke sr
11-20-2009, 11:32 AM
Glass bends so if there is a vacuum Put a straight edge across it and you should see it does not touch in the centre.
I did and I can put 4 Business cards under the centre

Roy Cooke

Bob Elliott
11-20-2009, 12:18 PM
Glass bends so if there is a vacuum Put a straight edge across it and you should see it does not touch in the centre.
I did and I can put 4 Business cards under the centre

Roy Cooke



Hi Roy, glad to see you posting buddy
Remember you from several years ago.

I was thinking along those lines and will start seeing if I notice that correlation.

Window glass does have a little flex to it as you can see when looking at reflections in a large store window.

Excellent point sir.

Vern Heiler
11-20-2009, 12:55 PM
It is the same technique I used when filling Glass tubes with Neon and Argon gas.
The vacuum draws in the gas but a vacuum still remains at the end.

Glass can support a vacuum and there are neon tubes close to 50 years or so still working well.

Some I installed 30 years ago are still going.

(sorry forgot to mention I did neon signs in the eighties)

Was there still a vacuum after the tubes got to temperature?

What is/was the temp in Ontario when you measured the glass?

How do we explane argon leaking out of a vacuum?

Roy Cooke sr
11-20-2009, 01:05 PM
In Home Temp is 74.0° F and outside temp is 48.5°F

Roy Cooke

Bob Elliott
11-20-2009, 01:12 PM
Was there still a vacuum after the tubes got to temperature?

What is/was the temp in Ontario when you measured the glass?

How do we explane argon leaking out of a vacuum?

It is not a perfect vacuum as that is true of most things in life.
From what I read that E glass has a lot to do with the thermal value also.

Still at R value of 2or 3 there sure is a lot of loss anyway.

Vern Heiler
11-21-2009, 08:41 AM
Dear Mr. Heiler:

Thank you for contacting the Andersen WindowCare® Solution Center. We are happy to assist you.

In our Low-E® and Low-E4® glass the sealed area between the panes is filled with an argon gas. The standard Dual pane is filled with air. If the units had a vacuum this would result in a greater amount of pressure on the outside causing the panes to collapse towards each other. While we do warrant our products against defect for a period of 20 years, with proper maintenance and baring outside influences our windows can still perform well beyond the warranty period.

We have included a statement of our limited warranty for your convenience. Andersen® Windows and Patio Doors are warranted in two ways. The glass in Andersen factory-glazed sash and door panels (other than special glazings, Art Glass and certain Flexiframe® products) is warranted to be free from manufacturing defects for twenty (20) years from the date of purchase or from the glass manufacture date. Most non-glass portions of window and patio doors are warranted to be free from defects in manufacturing, materials and workmanship for a period of ten (10) years from the date of purchase or from the glass manufacture date. This is a limited warranty and does have exclusions

Mr. Heiler, thank you for giving us the opportunity to assist you. Should you have any concerns or questions in the future, please do not hesitate to reply to the Andersen WindowCare® Solution Center via e-mail, keeping all previous messages intact. Your request number remains 7050869. You may also contact us by calling 1-888-888-7020. Our hours of operation are from 7:00 a.m. to 7:00 p.m. Central Time Monday through Friday and 8:00 a.m. to 4:00 p.m. Saturdays.



Sincerely,
Ben
Customer Support Representative
Andersen WindowCare® Solution Center

Bruce Breedlove
11-21-2009, 11:25 AM
From what I read that E glass has a lot to do with the thermal value also.


Low-E glass has nothing to do with the U-value of a window. Low-E glass does not increase or decrease the window's resistance to the flow of heat by conduction through the window.

Low-E (short for "low-emissivity") glass reduces the amont of radiant heat that passes through the glass. In the summer when the house is being cooled low-E glass can reduce the amount of radiant heat from the sun that comes through the windows thereby making the house more comfortable, reducing the head load and the amount of heat the air conditioning system has to remove and lowering the utility bill.

Vern Heiler
11-21-2009, 11:58 AM
Bruce this is the response I received from AW when I asked if there IGU's were sent from the factory with a vacuum. Nothing to do with low E.

Bob Elliott
11-21-2009, 12:07 PM
Low-E glass has nothing to do with the U-value of a window. Low-E glass does not increase or decrease the window's resistance to the flow of heat by conduction through the window.

Low-E (short for "low-emissivity") glass reduces the amont of radiant heat that passes through the glass. In the summer when the house is being cooled low-E glass can reduce the amount of radiant heat from the sun that comes through the windows thereby making the house more comfortable, reducing the head load and the amount of heat the air conditioning system has to remove and lowering the utility bill.

Semantics but I could have used better words.
It basically acts like a reflector the way I see it.
I would liken it to silvering a roof.

Bob Elliott
11-21-2009, 12:10 PM
Dear Mr. Heiler:

Thank you for contacting the Andersen WindowCare® SolutionCenter. We are happy to assist you.

In our Low-E® and Low-E4® glass the sealed area between the panes is filled with an argon gas. The standard Dual pane is filled with air. If the units had a vacuum this would result in a greater amount of pressure on the outside causing the panes to collapse towards each other. While we do warrant our products against defect for a period of 20 years, with proper maintenance and baring outside influences our windows can still perform well beyond the warranty period.

We have included a statement of our limited warranty for your convenience. Andersen® Windows and Patio Doors are warranted in two ways. The glass in Andersen factory-glazed sash and door panels (other than special glazings, Art Glass and certain Flexiframe® products) is warranted to be free from manufacturing defects for twenty (20) years from the date of purchase or from the glass manufacture date. Most non-glass portions of window and patio doors are warranted to be free from defects in manufacturing, materials and workmanship for a period of ten (10) years from the date of purchase or from the glass manufacture date. This is a limited warranty and does have exclusions

Mr. Heiler, thank you for giving us the opportunity to assist you. Should you have any concerns or questions in the future, please do not hesitate to reply to the Andersen WindowCare® SolutionCenter via e-mail, keeping all previous messages intact. Your request number remains 7050869. You may also contact us by calling 1-888-888-7020. Our hours of operation are from 7:00 a.m. to 7:00 p.m. Central Time Monday through Friday and 8:00 a.m. to 4:00 p.m. Saturdays.



Sincerely,
Ben
Customer Support Representative
Andersen WindowCare® SolutionCenter

Ok
Glad you got that settled.
No vacuum and some models actually do use air,so this has been a very educational thread for me.
I still suspect there is a slight vacuum however because that would be the best way to introduce the gas.