SBS - The Best Value in QMS software

Vinyl Replacement Windows - 'Weeping' condensation at Glass / Vinyl Interface


Fully vaccinated are you?
Staff member
Ummm, well - I had replacement windows put in. Sorta - They screwed up the size of the kitchen windows so they're not in yet. Anyway, I'm looking for information. These are the specs on the windows (such as they are) windows: - It says: "The G.10 offers performance comparable to an insulated wall."

The problem: The windows are 'weeping' at the glass - vinyl interface in the mornings. Temperatures here have been moderate lately - In the high 30's to 40's. Relative humidity inside stays between 40 and 50% RH (Yes, I use a humidifier). Indoor temperature ranges between 68 degrees F and 73 degrees F. This happens even when I leave the curtains open all the time including at night. Yes, when I shower the bathroom windows do fog up a bit, but that's expected in a bathroom when showering, even with a standard bathroom vent fan.

How do I know for *sure* the temperature and humidity in each room? Here are my Oregon Scientific BAR112HGA sensors:

Yes, I'm a weather and air flow freak... I wish I could feed the data from each into my computer every minute or so...

Anyway, I've stabilized them all here together for about an hour (note the one remote with the -5 red tag - it typically reads 3 to 5 degrees high). I keep one 'main' sensor in the living room on desk, one in kitchen and one in master bedroom. I move the remotes around from time to time, and the 'red tagged' one I use outside.

Weeping was REAL bad (as in puddling) the one night it went into the mid-20's here. I can't imagine what will happen if it really gets cold here... This morning was about 40 so the 'weeping' was slight. See: Windows Weeping at Glass-Vinyl interface

This is the construction:

I also have a replacement sliding glass door with the same "G10" glass. It doesn't 'weep' at the glass-vinyl interface.

My dilemma - IF the window is, as advertised, "...comparable to an insulated wall..." should this be happening? The walls aren't sweating and the windows don't fog up or anything like that. The bathroom off the bedroom is always colder than the bedroom and those windows don't 'weep' at the glass-vinyl interface.

I did find this: Window Condensation discussion:
tru_blue said:
I'm going to throw a lot of statistics at you to address condensation on your windows. Keep in mind that these stats are based on a worst-case scenario of 0° outside and 70° inside, which sounds like it may apply to your climate but is not applicable to warmer, southern climates.

Now for some stats. If a window is clear double glazed insulating glass (doesn't matter if it's wood or vinyl), the center-of-glass roomside temperature would be about 44-45°F. (Incidentally, single pane windows with a storm window would be about the same) Adding a Low E coating to the glass bumps it up to about 52°F, and Low E insulating glass with Argon gas raises the glass temperature to 57-58°F. Not bad for 0° outside. Presumably your Renewal windows are Low E with argon gas.

However, with insulating glass the edge-of-glass temperatures are much lower than center-of-glass. The type of spacer that separates the panes of glass greatly affects the edge temperature, and much could be said about the merits of different types of spacers. Naturally, condensation, and even ice, would normally occur at the edge first, since that's the cold "weak spot." Clear IG with an aluminum box spacer has an edge temp of only about 29°F. Low E glass with an aluminum spacer only raises it to about 32°. Then there are "warm edge" spacers, which are warmer and provide more condensation resistance. Stainless steel spacers (That's what Andersen mainly uses) are about 37° edge temp on a Low E/argon unit, and presumably (don't have exact stats on this) Superspacer and TPS (neither are used by Andersen) would be at the top at 39-40°. Again, warm edge spacers typically range from 35-40°, but still tend to max out usually in the upper 30°s. So Andersen didn't as you worded it "forget to do something with these windows like perhaps a seal or a window glass problem;" it's normal for windows to be colder on the edge than they are in the center.

Now for the fun part. If you cover a Low E/Argon gas unit with some type of roomside window treatment such as a shade, blind, etc., the center-of-glass temperature drops from about 57° to only 36°. That's an amazing 21° drop. I don't have any exact stats on what that does to the edge temperature, but I would imagine it must drop 5-15° as well. The reason it drops is because the air in the room is no longer freely circulating against the glass. Even a couch or desk in front of a window will significantly reduce the glass temperature if the furniture is partially blocking part of the window.

Is anyone here by chance involved in manufacturing vinyl replacement windows?

Anyone here have replacement vinyl windows? If so, do you have the same problem?


Elsmar Forum Sponsor

Wes Bucey

Prophet of Profit
I got the Anderson Renewal windows (brand name) installed just before Christmas. I haven't noted a similar problem, but then I don't keep the interior of my home as humid as you. Our shower vents do remove the water vapor and we get no condensation on mirror or windows.

Doing a lot of cooking doesn't seem to trigger condensation, either.

My suggestion is to take some high pixel photos and send them to the manufacturer (not merely the installer, unless they are all the same company.) Include the same type of data you have included here (temperature, humidity [indoors and out for both], air circulation against the windows, etc.) and ask for "remedies." (Don't be specific about exactly what remedy - hear their suggestions first.) Every manufacturer has slightly different warranties and guaranties.

I congratulate you on the heat distribution throughout your home, because my sprawling ranch can have a spread up to 3 or 4 degrees F. unless I run ceiling fans to aid air circulation.

I replaced some aluminum windows and some wood (Pella) just to have uniformity throughout. I notice absolutely no difference between the Renewal and the Pella, but a world of difference between the Renewal and the aluminum.


Fully vaccinated are you?
Staff member
Gilkey is a rather big company. Not Anderson, but it's pretty big between Chicago and Lexington, KY. The pictures I took were with an 18mm - 55mm lens on a Canon Digital Rebel XTi (10.1 megapixels). The pictures are in the 'gilkey' directory linked to above. All things considered, I think there was a problem in the bonding process on the bedroom windows. But, I'm trying to get more info. It's 50 humidity in here right now, but it's 73 degrees, it's raining outside and about 51 degrees with 94% humidity. However, right now they're not 'weeping'. I've just taped sensors to the windows where they weep but I'll have to wait for a cold night. It has really warmed up here. There are even some trees budding! It's really weird weather wise here. I've never seen a winter like this here in the Cincinnati area.
What you describe is typical for an old window where the thermal barrier/seal has broken down. I have had a number of situations like this - with cheaper windows, generally. I've got a couple right now like it - a small patch of wet appears within the sealed unit. If yours are like it as fitted, then I'm guessing they were made wrongly and are defective. With a gas filled/vacuum situation as is supposed to exist in a double/triple glazed unit, there should be nothing to precipitate out like that.



Fully vaccinated are you?
Staff member
...a small patch of wet appears within the sealed unit...
These are brand new windows. The 'weeping', when it happens, is not on the inside of the glass in the window so the actual 'glass packs' appear OK. It's at the glass-vinyl interface on the inside of the house side of the glass. If you walk up to the window you can wipe the sweat off.

It's warm here this AM so no 'weeping'. I'm going to have to watch for a bit, but it starts when it hits the mid- to low- 30's and starts getting severe when it hits the mid- to low- 20's. I'd hate to see what happens when it hits the teens or below.

Steve McQuality

Quality Engineer
Good Morning Marc!

In a past life, I worked for an independent test lab that certified windows for all the major and minor window manufacuturers for thermal, structural, air infiltration and water/rain performance. There are several test agencies for fenestration products out there and many standards for testing (i.e. ASTM, AAMA, NFRC (National Fenestration Rating Council)...there may be a couple others, I can remember). Do (or did) the windows have any NFRC or the like stickers on them? Did your old windows "weep" like these do?

With the humidity level you keep in the house, it sounds like your hitting the dew point on the window surface. This may or may not be a defective window (it was about 12 years ago, and some of the specific design and test details are a little foggy now - excuse the pun:rolleyes: ...). One word of caution - you mentioned that your walls don't "weep"; that's probably because your construction involved a vapor barrier within the wall cavity, so the condensation - if any - is within the cavity of the walls, not on the surface. An additional word of caution is "Do NOT plug the weep holes on the windows". Windows, if properly designed, are designed to handle condensation and the condensate is designed to flow out of the window. If you removed the IG (insulated glass) you'd see weep holes drilled into the bottom stiles of the sash, directing the water to the exterior.

If you'd like to research a little more info on window testing, performance and design, try the NFRC web site ( You should find some useful information on their site and links to other info.

Since I'm on this discussion now, I'll keep my eyes open and if any of the fog lifts on any old memories, I'll try to help you out. There is a possibility that you have air infiltration around the lites of glass (inproper installation of window stops on the stiles, improper fitting of the weather strip) but at your higher desired humidity levels you may be seeing "good" performance by the forming of condensate on the surface (that's the part I can't remember too well). If you see condensate between the glass as Claes has mentioned, then the IG (insulated glass) has failed and you need to get replacements immediately if still under warranty.

I just hopped onto the NFRC website while I was writing this reply - Anderson has some good info on their site as well, FAQ's and the like. That may help you understand what's going on as well.

I hope this helps a little and at least points you in the right direction. Good Luck!

Thread starter Similar threads Forum Replies Date
P MSDS for MVQ FDA White, Vinyl Methyl Silicone Rubber EU Medical Device Regulations 4
D IMDS for Like Components (Interior Plastic, Leather/vinyl Armrest, etc.)other than Color APQP and PPAP 1
P PMMA IRK304 Resin and EVA (Ethylene Vinyl Acetate) Tape causes a Stain Mark Manufacturing and Related Processes 3
M Vinyl and Cloth Cut Parts Tolerances? (Car Seats) Manufacturing and Related Processes 8
Jen Kirley Have you tried recording vinyl to MP3s and or CDs? Turntable with USB port? After Work and Weekend Discussion Topics 22
T Tensile / Pull test standards / Specimens - 14 mil vinyl interior products Quality Tools, Improvement and Analysis 6
Juby Tan Action on Customer Replacement (Nonconforming Product - ISO 9001) Customer Complaints 2
C Serialised Defective Part Replacement EU Medical Device Regulations 4
F Replacement Bone Screws - Traditional 510(k) or Special 510(k)? Other US Medical Device Regulations 7
J Implementing Machine Replacement Part Reverse engineering technology Manufacturing and Related Processes 4
A Distributing Replacement Parts for Class II Medical Devices Other Medical Device Related Standards 13
L Balls drawn without replacement probability question Brain Teasers and Puzzles 8
L Replacement of SAC305 Solder for SN100C Lead Free Solder? Manufacturing and Related Processes 1
Q Spare Parts - Sourcing a small replacement part Manufacturing and Related Processes 5
B What is the FDA guidance regarding selling replacement parts and traceability? 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 2
M Identification and labeling medical device replacement system components Other Medical Device and Orthopedic Related Topics 12
Marc CBS Taps the Real Stephen Colbert as Letterman's Replacement After Work and Weekend Discussion Topics 1
B Replacement anvils for Helios UMG 50 General Measurement Device and Calibration Topics 3
J Does TS 16949 audit replacement parts? IATF 16949 - Automotive Quality Systems Standard 2
B Tesa-hite 350 Gage Display Replacement Calibration and Metrology Software and Hardware 12
Marc Cataract Replacement Lenses and Surgery Coffee Break and Water Cooler Discussions 7
A Tool Wear Rate/Replacement - Turning/Facing Manufacturing and Related Processes 1
1 Quality VP/Manager left - Educating his replacement Quality Manager and Management Related Issues 9
R MIL-STD-120 replacement? Calibration Work Instructions refer to MIL-STD-120 ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 1
K Organization's Rights vs. Customer's Rights - Product Return vs. Replacement Customer Complaints 13
F Measuring Ceramic Tubes & Discs - any suggestions for replacement of calipers? Manufacturing and Related Processes 6
Q Scrap + Replacement always? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 8
J "Gaging" the performance of a replacement gauge Capability, Accuracy and Stability - Processes, Machines, etc. 6
B Partial Joint (Hip Prosthesis) Replacement Class inquiry EU Medical Device Regulations 3
S Why should we never re-use an identification number for a replacement M&TE? General Measurement Device and Calibration Topics 7
Icy Mountain TS 16949 Requirement for New MSA for Identical Replacement Part Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
S 5 Ton Water Cooled Chiller for Thermotron Need Replacement Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
G Document replacement - How would you migrate the old to the new? Document Control Systems, Procedures, Forms and Templates 6
Marc If GM and/or Chrysler go under... What about replacement parts and dealerships Coffee Break and Water Cooler Discussions 16
S Rechargeable NiMH Battery Life in Medical Devices - Replacement Intervals Other Medical Device and Orthopedic Related Topics 2
L CE marking on medical device components/replacement parts EU Medical Device Regulations 5
Q Tyco TMS 2000Plus Replacement Manufacturing and Related Processes 1
M Design Validation of class 2 medical device - Vertebral Body Replacement Design and Development of Products and Processes 4
ScottK Quality Manual Replacement Action Plan from EU Pressure Equipment Directive Compliant Quality Management System (QMS) Manuals 4
W PPAP Submission Items - Metal Stamping - Tooling Transfer, Replacement, Refurbishment APQP and PPAP 6
Marc Bank of America: Train your replacement, or no severance pay for you World News 14
H FDA ASTMF1100 replacement? We want to market an emergency care ventilator ISO 13485:2016 - Medical Device Quality Management Systems 3
A Automotive Replacement Parts Market QS-9000 - American Automotive Manufacturers Standard 4
C Statistical technique sought for predicting replacement of perishable tooling Statistical Analysis Tools, Techniques and SPC 14
B Does anybody know how to get older versions of Minitab to work in Windows 10? Quality Tools, Improvement and Analysis 9
Ninja Windows 10 100 % disk use after update Coffee Break and Water Cooler Discussions 33
G Windows 10 OS build Software Validation US Food and Drug Administration (FDA) 1
Claes Gefvenberg Windows 8.1 - Pros & cons, hints & tips. After Work and Weekend Discussion Topics 5
Jim Wynne Windows 8.1: No Security Updates Without Update 1 After Work and Weekend Discussion Topics 4
Marc Windows XP EOL scamware After Work and Weekend Discussion Topics 1

Similar threads

Top Bottom