Window Condensaton Redux

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I know this is a timeless topic that never seems to die, but it's that time of year where my windows drive me insane again.
The house was built in 1997 with Pella Architect casement windows and extra insulation in the attic, and I'd also place money on the furnace being undersized. To add insult to injury, when the contracters installed the ductwork, they made the mistake of routing one floor register vent into the cold air intake box.
This is the third year I've lived in this house, and fighing window condensation seems to be a yearly obsession of mine. If wouldn't give a rats patute about the condensation if it weren't for the fact that if starts to run, and freezes on the seals and on the wood itself.
Right now, my humidity is high (50%), but I have the same problem with condensation at %20-25. It starts with the two bedrooms and master bath upstairs, but eventually, it makes its way to all of them. Now, those two rooms and that bath have their doors closed all of the time due to pets. I'm sure that's not helping air flow either.
Here's what's happened so far:
The end of last season, I have a local HVAC guy stop buy. His take: negative pressure. He also pointed out that the AC fan was wired to HIGH, and the Heat fan was wired to LOW. I promply set the heat fan to MEDIUM, and that appeared to make a difference during the last month of winter (Ohio winter). But, since we didn't have many bad days by then, maybe that was a fluke.
As usual, I've cleaned all of the frames to get out the webs, nests, dirt, grass, etc. I've clean all the weap holes, and I've put a new coat of UV rates poly on the wood frame between the outer pane and the inner removable doublepane so they're not sucking mosture. The poly they used when the house was new was clearly not UV rated since it was peeling like crazy. But I digress...
Here it is, October 17, at ~40 outside, and the fun has already started with condensation for the first time this morning. The house usually sits around ~65F and I haven't turned the gas furnace on yet.
We just ordered glass doors for our wood burning fireplace insert with the plans of burning much more wood this season due to the skyrocketing gas prices. The insert has an outside air source vent, and a blower to blow the box air back into the house. With any luck, the glass doors will do their job and keep the heat I have in the house. :-)
I also turned the furnace fan on this morning just to help with circulation. Who knows if it will make any difference.
While cleaning the windows, I've taken notice of the fact that the rubber seals they put on those things suck serious butt. In some cases, the seal is so flat, it can't be sealing against the wood frame well, if at all. Combine that with negative pressure, and you have a real good time.
I'm toying with the idea of getting some thin weatherstripping, and trying on of the problem windows to see if that helps.
They are plenty of directions to go from here, but I can't seem to find anyone local who really knows their stuff. Any thoughts?
-=Chris
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My guess is that the air leakage around the windows is the culprit. Cold glass of water, warmer room = condensation. Try putting a thermometer next to the window and see how that temp, near the glass, compares to the room. Someone else can probably tell you the exact temp differential that will trigger condensation at what relative humidity.
If the seals on the windows are OK then possible the space between the jambs and wall is not insulated. You could remove some trim and stuff some fiberglass in behind the trim. If the seals on windows are bad I think they are replaceable. Talk to a pella dealer, I do not recall the warranty but it doesn't hurt to ask.
I have 16 of these same windows in a cottage and I have never had condensation. Its not a year round place but I do heat it in the fall and spring with an unvented propane heater. These add a fair ammt. of moisture and I still do not have an issue.
Your post contains a few red herrings - Fireplace, HVAC, etc. in my opinion.
You can also help the situation by lowering the relative humidity. Bathroom vent fans when showering could help. Dehumidifier could help although many want more humidity on winter but in your situation...
Anyway - Focus on the air leakage around the windows that's your likely problem.
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No wrote:

I've oft wondered if this was accurate thought. These windows are big, and the coldness of the glass alone would make the temp next to them drop, even with no draft or leakage, I would think.

My last conversation with Pella ended with them wanting $150 for someone to come out and inspect the windows. Maybe it's time to get it from the horses mouth. Most of the stories I've heard end up with "the were installed wrong. tough luck for you".

I've got vents in both bathrooms, and I've tried cracking the windows when I shower. I've even tried a humidifier without much luck.

Cheapest solution first..a little foam to test a theory.
Thanks, -=Chris
:-)
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Hi, Chris.
Such condensation indicates that the air next the window has dropped below its dew-point. You probably know that. :')
My bet is that the windows are sufficiently conductive that the temps drop enough to ... you know the rest. If you don't have storm windows, they will help, as will plastic film inside, to reduce heat loss. There are sealing & insulating curtains that work well, but might not be to your taste; with such, the inside of the glass would be colder yet, but at least isolated from inside airflow.
What is the allleged r-value of the windows? What are your options for replacing them with something less lossy?
Good Luck, J
Chrisotpher H. Laco wrote: <snip>

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If these are casements that are single pane with a added removable second pane then they are not true double pane glass, they have no gas inbetween, air seal, or E coating. Their R value is probably 2, vs 3.3 for sealed dual pane, and R1 for single glass. If they open then pella probably has Tri pane replacement sizes. I dought leaking would make matters worse as it will equalise interior air vs outside temps near the window, Therefore a leaking glass would condense Less.
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m Ransley wrote:

The removable inner part is two panes together, at least it looks that way. It's certainly much heavier and thicker than a single pane piece of glass.
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m Ransley wrote:

thus far. Oddles of opinions, but no experts in town to actually say with confidence, this is it. :-)
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Well so far chris you dont indicate or show a true knowledge of what you even have in glass, you say dual pane removable which would be R 2. So it all might be normal.
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m Ransley wrote:

Sire I don't. I don't make windows, nor did I purchase the initial windows to know what their specs are. All I can say is what I see. THe internal removable pane is twice as thick as a normal pice of glass.
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You have to be a bit careful with designating Pella glass type. The removable pane shouldn't really be counted, because for the most part all it does is protect the interior blind or whatever from physical damage, and it has relatively little insulation value. It's not sealed very well, and the glass-glass gap is too big.
What really matters is what the non-removable glass in the sash is. We're looking at Pellas now, and as far as we've been looking, the options for that are two layer thermopane with low-E or three layer thermopane with one or two low-E layers.
We're trying to match some existing non-treated triple thermopane, and the modern low-E double thermopane is equivalent.
If you're getting condensation when the interior conditions wouldn't suggest it, I'd strongly suspect stale air near the windows. There's a reason why they put heaters/heat venting below windows...
The removable panes would accentuate the condensation problems - leaks new moist air, but it doesn't circulate very fast.
We have no intention whatsoever to equip our windows with removable panes.
Try taking them off and see what happens.
--
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
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Chris Lewis wrote:

No, I don't think it's that style of window. The removable has a big rubber gasket on the back of it to seal the window pocket between it and the outer pane. In that pocket there are 4 weep holes, 2 top, 2 bottom.

True. And that's where the mystery starts. Whether the heat is up, or down, or whether the humidity is high, or low in the how, the condensation happens, and without much of a pattern.

I don't think it's that kind of window. If I removed the internal removable pane, there would be 4 big weep holes in there to let my hot air out, or the cold our in, and yes, only the single pane on the outside, bound uner the vinyl exterior.
In fact, here it is...pre 2005 removable glass casements... http://www.pella.com/maint/blinds/casement.asp?path=/maint/blinds/casement/designer
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Actually, that (Designer type) is exactly the kind of window I was referring to. Didn't realize that it had weeping holes. Tho, that's not entirely unusual in other kinds, even without an inner barrier (some sorts of sashless sliders for example);.
If you have single pane on those, no wonder they have a condensation problem.
We've decided for other reasons to not go with these. Looks like we're going for Loewens.
--
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
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You state the outer pane is half as thick as the interior removable pane. If you had dualpane anywhere you would notice a metal strip separating the 2 panes, giving you a tri pane. This condensation issue may be basicly normal for that design if the seals are poor. Without Low E argon sealed units you are probably R2 vs R 3.3 for sealed units. You have a 10 year warranty, I`ve had seals replaced for free on new Pellas, call the window company it seems to be a window issue not a true high humidity issue. Even sealed Low E argon Pellas consumer reports rated poor in condensation. A window rating overlooked by 99% of the people is CDF Condensing Factor, Windows and glass are not made equal as most people think.
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m Ransley wrote:

Next available Pella serivce date: December 5th. :-/
I would give my kindom just for a pattern..windows that consistantly have the problem; but it's so touch and go it seems.
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snipped-for-privacy@sme-online.com wrote:

:-)
I've always wondered about those casements. Double-pane removable in the intior..and the vent holes between th exterior pane and the outside cold world...

As soon as I win the lotto. I've got 12 of the huge casements, and 4 of the halfsize casements. If I'm going to spend that kind of money, might as well let them cook for a few more years.
The funny thing is, my vinyl clad double hung aluminums in the basement never condense, and it's about the same temp/humidity down there right now. Actually, the barely sweat, right in the corners where the foam is probably not so tight.
-=Chris
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Pella condense quicker-at higher humidities than other glass, go online Consumer Reports they have an extensive old rightup, a good article.
You humidity needs to be acuratly monitored, analog humidistats need to be calibrated and 99% at stores are 10-20% off New and can`t be calibrated. Get a few digital units and learn what your humidity is, possibly a window lost its argon but doughtfull,
Call Pella they are under warranty Your new house is tight new construction? with Tyvek? Possibly an air exchanger is needed a blower door test apx 300$ will determine it.
Well of course you keep doors closed and no air circulates, Open Them.
Get a few pros out, we are not there.
In fall when heating season starts indoor humidities are higher before you dry out,
Get a dehumidifier, and learn Your House, high humidity will ruin the pellas wood, the Poly was not bad but your letting this occur continualy will ruin all your finishes and Pellas .
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m Ransley wrote:

Got 3 Oregon Scientifics humming along. I'd say they're as accurate as the local weather staton as they usual line up (the outside one that is).

No clue since I'm not the original owner. I've had to HVAC people tell me an exchanger would not solve my situation.

Well, there's one door; no storm door. That won't work. :-)

The problem is finding them locally that know anything. They all have theories, and most of them don't line up with an exact "do thins and it will be solved".

Indeed. But like I said, I have the same problem mid season with %20-%25 humidity indoors.

Tried it three times, two different units in two different rooms. It made no difference other than noice and heat.

I don't agree 100%. A good UB rated poly would not peel between the windows, on the inside frame where it not exposed to direct wetness. It's all sun wear.
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"My last conversation with Pella ended with them wanting $150 for someone to come out and inspect the windows. Maybe it's time to get it from the
horses mouth. Most of the stories I've heard end up with "the were installed wrong. tough luck for you".
Glad I have Anderson, though I don't know if they would come out and take a look without a charge either. How old are these windows? I would hope that if this were reported back to Pella within the first year or so that they would send a rep to look at them for free. In any case, if they won't come for free, at this point, if I were you, I would pay the $150, and start with Pella, as one would think they would be one of the best sources for problems with their own product.
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You probably have a tight well-insulated house with a good qty of insulation in/above the ceiling. What has probably happened is that when the insulation in the attic/ceiling was laid, it covered up the eaves thereby blocking passage of air in the attic. Check this & ensure that you have good circulation in your attic that removes all moist air with good cool dry outside air. I feel comfortable in saying that this will solve the condition. Ashoke - heating.products.bz
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