Dear Readers,
Does anyone know where I can get do-it-yourself materials to correct foggy windows (ie. Moisture that gets trapped between glass panes)? I have heard about a simple process of drilling holes and installing small vents. However, not sure where to best drill the holes and where I would get small vents to insert. Please don't reply with "replacement is the only option", because it is not. Thank you.

If this is a thermopane window I am afraid you are out of luck. The sapce between the panes was originally filled with a gas that has now escaped and been replaced with air and humidity. The same question was asked on Bob Vila's home site and talked about drilling 1/8" holes at each corner. The poster asked if anyone had any luck with this, the post sat for 90 days without a response.

Thanks Ballengerb1 for your reply.

It should not make a difference what was formerly in between the panes or that the absorbent material has reached it's saturation limit. It is simply that warm moist air in between the panes condenses when it hits the inside of the cooler pane on the exterior side of the door. It is ridiculuous, I think, to pay hundreds of dollars to replace doors or windows with this problem. That's what contractors and window people want us to do. So I will apply my knowlegde of chemistry and physics and let folks know how I do. The trick is having drier air inside (dehumidify) and small vent holes drilled into the glass from the inside. Logically, the moist air in between is no longer "trapped" and can be replaced with drier air from the inside.

The key is the moist air needs to escape and be replaced with drier air "continuously" and at a faster rate than the moist air entering. It is that simple! I was hoping to find "do-it-yourself" kits with instructions on the correct size holes and vents and how many and where, etc.

I'll report back on progress. Thanks again.

It is a bit more complicated. All room air has some moisture in it and that air is now inside between the panes. As indoor and outdoor temps change during the night/day condensation will happen, also a small amount of dust and dirt are in the air. The original gas that was inside the window did not have dust, dirt ro the ability to hold moisture. If you could hook up a tiny fan or blower you would see a lot less moisture but you would also see a lot more dust/dirt. Best of luck with this one but I think you are headed to where you said you did not want to go, the window store. Most thermopanes have a warranty that could be good for up to 15-25 years, how old is your window?

We install windows for 225, this includes the window for an average opening. I think you'd spend more time and money trying to do this yourself, in fact it all you need is a sash, you may be looking at 100 or less.

As for window stores out to get you, I can't speak for them but for contractors I can, our goal is for you to be happy with the work so you'll call us back, if our goal was to cheat you with cheap windows and poor installation we would be in business, things like that just happen, I installed my windows in my own home and one went bad after just 5years, anytime you have any production of a product you going to have those bad eggs,
Bit the bullet , save your time, and money and just buy a sash.

TKNoll, you are correct in almost everything you said about drilling the glass, dryer air, etc. However, DO NOT try to drill the glass on any door - it will shatter. Door glass is tempered and therefore will break into thousands of small pieces when you try to drill it. Hope I'm not too late!!

That said, let me clear up a couple of myths about Insulated Glass Units (IGU).

First, most are not manufactured with Argon or Krypton or any other heavy gas. Argon is usually considered an upgrade and will cost more money, therefore most people don't spend the money. Most windows are made with dry air.

Second, IGUs do not have a perfect air tight seal - it is semi-permeable. Let's use your physics for a minute to explain how the moisture got in the window. During the heating of the day (especially in direct sunlight), the air between the glass heats up, expands, and creates pressure inside the IGU. That pressure forces a little bit of air through the seal. At night, the air cools down, contracts and creates a vacuum - sucking air through the seal. Since there is moisture in air, the window starts to accumulate it. The window manufacturers put a desiccant in the spacer bar (that holds the two pieces of glass apart) to absorb the moisture - great solution. Unfortunately, the desiccant gets saturated over time and can't hold any more moisture. That's when you start seeing the effects of moisture inside the IGU. That process is called Solar Pumping.

The holes in the glass allow the IGU to breathe (that's what it was trying to do - just not effectively). Now, during the expansion cycle, the air goes out through the valves and takes the moisture with it. That's how we dry the air out - and keep it dry.

This is not a do-it-yourself project. Drilling a couple of holes in the glass sounds easy but there's a lot more to this process then just drilling the glass. Like knowing not to drill door glass, etc. Leave the window restoration process to the professionals - we've been trained to know how and when to do what we do. It is cheaper than replacing (when appropriate). I'm not trying to discourage you from doing it because I want to make money off you - I don't even know where you live. I'm discouraging you because I don't want you to create a bigger problem than you already have, possibly getting hurt in the process.

Chattanoogawindowmedics.com

Good response... quick question, I know that tempered glass usually brwaks if it's hit on the corner, with that said then would drilling a hole at the bottom still cause the glass to shatter?

Absolutely, tempered glass cannot be drilled.

OK I have a question. I've had watches and phones and all manner of 'sealed' glass devices in the past. Sometimes condensation builds up in them and I simply put them under a light bulb long enough for the moisture to dissipate.
This has worked even with cell phones for me that are not totally filled with water (dropped in some water).
Is it possible to apply the same principal to a window/door which - if I'm understanding correctly - has some kind of permeability for the moisture to get out?
In other words can I put a hair dryer to the window and dry up the condensation?