No familiar with the post that you are mentioning, and there's a pretty good chance that SusanM05 isn't going to see this either since the date you mentioned on her post was 9 years ago, but have you contacted Pella to see if they can be of any help?

If you have double pane glass and the condensation is as you say "in between the panes". You have a seal failure and need to replace the glass. Most every window company I am aware of (other than Andersen) the warranty for this is 10 years so you need to pay for new glass.

In response to millworkman; the inside pane is a removable pane, so it is not really a sealed unit, as I think you are thinking. I can remove the inside pane in order to get to the blinds between the 2 panes, clean the inside glass, etc.... So if I'm keeping the breather holes clear, the only other thing I can think is causing the excessive condensation might be that the seal between the removable pane and the window needs to be a better seal. SusanM05's question (along with mine) is whether the seal on the removable pain is the issue, and if so, what is the best way to remedy this?

In response to andreak100: after reading many stories about Pella, I don't have much faith they will help, but I will consider it if all else fails.....

Sounds like what you have is different from what's most common. Most multipaned units are sealed around the edges and the two panes together are enclosed by a frame to form one piece.

To replace a failed "unit", the unit is taken out and is replaced by a new double paned piece. I have a lifetime guarantee on a house full of windows and I've had maybe 5 individual units replaced because of moisture inside. Mine most certainly don't have drain holes, that would let in moisture (and air) and defeat the purpose of the double panes to begin with.

As others have said typical double pane glass is an insulated glass unit (IGU) with two panes permanently sealed together with dry air in the cavity space to prevent condensation when the outside air and inside air have a large temperature differential. Looking at the Pella site I assume that you have double pane glass with blinds between the panes. There is no "seal" between these panes so to minimize the likelihood of condensation on the interior surfaces, steps should be taken to keep the temperature and moisture conditions in this interior space below the dew point for the air in the cavity space. attached is a link to the Pella support site and they have a condensation manual that explains the phenomena and how to deal with it. You don't say where you are located but if you're in an area where the difference between the outside temps and the inside temps are expected to be large (i.e. winter conditions in the north, or summer heat in the south) then they should have sold you IGU's and not this system.

Hope that helps.

Here is a link that might be useful: Pella condensation manual

It would seem that for this kind of, vented, system to work, you would need to be able to select between vented to the inside or the outside. You'd want the vent on the low humidity side and that might change from season to season.

I don't know the details of the construction of these windows. I'll assume that the vented air space between the outer,removable pane and the inner two panes is in contact with a permeable material that is in contact with the dry, inside air.

If that is the case, plugging the vents should work. You want to have that space "open" to the environment that is more dry on average during that season. In the humid summertime, that would be inside with air conditioning. The moisture will pass through the frames and dry to the inside.

In the winter, the air outside is typically drier than inside, but I am not sure that the difference will make it desirable to remove the plugs. I think that I'd try leaving them in and only remove them in the winter if I saw a problem.

In the old Pella owners guide it states to finish between the two panes of glass. I know if the paint or the finish is old, it starts to break down allowing moisture to come through the wood. Also check to see if the glass is tight against the exterior clad/wood and caulk as necessary.

The interior panel of glass (DGP-dual glazing panel) if not seated properly (clips all in) it will allow roomside air which will also cause moisture between the glass. Make sure all clips are in and the gasket is not brittle or broken. If so, contact your local Pella service department to order a new gasket.

If you have wood muntins (grids) make sure they are finished. They too can create moisture between the glass.

My bet is you notice on only a few windows when the weather has changed. My 1979 Pella's now have a little moisture with the winter but they are in great need of painting. They did not do this prior to this year. Painting them and checking that they are caulked properly should fix the problem.

If you understand that the glass needs to have some outside air to minimize condensation, then keeping the breather tubes clear of bugs and debris is important. Knowing that there are other possible issues will help to fix the issue.

Hope this helps...

I just tried chatting with the Pella people about the purpose of the "vent" holes. Here is the totally useless information provided.........

Michelle: Hello, thanks for contacting Pella Window and Door. My name is Michelle, may I have your name?

You: Hello Michelle. My name is Ted.

Michelle: Hi Ted, how may I help you?

You: We have a house that was built in 1977 and has many Pella casement windows. I'm contacting the chatline because I've been unable to find an answer to my question on the Pella site. What is the purpose of the holes in between the glass panes? From what I've read they are supposedly vent holes, but why are vent holes needed? Thank you for any info.

Michelle: One moment please

Michelle: Thank you for your patience. Which city/state are you located in?

You: central ILLINOIS

Michelle: I see. We serve clients in Milwaukee, Madison, Green Bay, Appleton and Brookfield (WI).

You: Ok. This is a question that is not location specific. The purpose of the holes doesn't vary by state does it?

Michelle: I apologize this information is not in front of me at the moment. However, one of our specialists can discuss this in greater detail. We can be reached at 920-735-0505 – 800-242-1008.

You: Oh, boy. So, if someone were to contact you with the same question but from one of the mentioned cities, you'd be willing to answer it?

Michelle: Ted, this information is not in front of me at the moment. Feel free to contact at the given number

Old Warranty Book. I have an old scanned copy of old Pella Warranty.

I does tell what you can do to maintain the windows. The holes are breather holes and they need to be cleaned. The wood between the panes of glass also needs to be refinished (painted or stained again). Caulk the outside pane of glass and also check that the dual glazing panel (inside removable panel) gasket is not cracked or worn.

I hope this helps.

Late to this conversation but have same issue of extreme condensation especially after heavy wind driven rain on humid day. Also extremely hot days with direct sun on Windows results in condensation. The situation is driving me crazy. Anyone with condensation issues find a solution?

If you refer to the old owner's manual https://onedrive.live.com/?cid=92134c2b85ec85f9&id=92134C2B85EC85F9%2118316&ithint=file,pdf&authkey=!AHngNG-tCn0I9lc it will instruct on what is needed for maintenance on older Pella windows and doors with the wood between the exterior glass and dual glazing panel. Hope this helps.

Any insight on use of breather plug? I believe the condensation is caused by breathing vent and extreme humidity being allowed to enter via breathing vent. I am about to order breather plugs for 26 windows total cost $475. I am disappointed at performance of the Pella Windows.

Hey Kevin,

Any luck with using the breather plugs? I have the same issue with the same openable Pella windows. I spent last summer sanding, staining and resealing the interior wood work, yet am still having this issue. Which plugs did you order? And did you try different configurations of pluging ( top only, bottom only, all 4?) and which worked best? ---- Also, has anyone found where and how to order new gaskets for the interior window pane?