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Double Pane Window Has Fogged Up

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Does anyone know how to unfog a double pane window? One pane of a 4 pane picture window is all fogged up between the thermal windows. It looks awful! Help!

Amy from Prospect, CT



Recent Answers

Here are the recent answer to this question.

By Peeeldee03/11/2012

I had read about drilling holes to vent the moisture from the glass, and also about putting solutions inside the panes to dissolve the mineral buildup on the inside of the glass panes, so I tried it.

Drilling the holes requires a diamond drill bit and patience. However, even after a couple of weeks it didn't change the appearance of the fog, in either the badly fogged or the minimally fogged test window I chose.

Tried filling windows with vinegar and soaking overnight before draining. Didn't work, so I tried Calcium Lime Rust remover the same way. Didn't work.

Tried taking glass out and cutting the seal. The minerals inside were rock-hard. Using a razor scraper and CLR, I was able to clear about 10" by 10" of window pane in about half an hour. Mind you, that is on only one of the two panes of the double paned window. Quick arithmetic told me that the value of my time was worth much more than the $60 per window I had been quoted to replace the glass.

I am now enjoying my newly-installed clear windows!

By Paul Lacey05/11/2009

Go to

They have service providers around the country who can give you a quote and repair your fogged windows.

By PFVF05/04/2009

Your windows likely can be restored in place without removing them (or having to replace them). There is a company with operations in Canada, the United States, and Great Britain.

See here:

By Greg Morrison02/16/2009

When it has fog between the glass, it well get worst. You are losing your insulation value when this happens. Most units today come with a 10 yr. warranty. Check with your builder or glass company where you bought the unit from for warranty info.

eastcoastglass at yahoo dot com

By carl (Guest Post)12/03/2008

Dear Amy,
you have lost vacuum seal and humid air has been sucked between rhe two pieces of glass. The seal is still good enough that the humdity can not even out with changes in humidity. The water condensates on to the glass fogging it up. If the glass isn't tempered (safety glass) I would try and drill a small hole through inside pane with a glass bit and put grains of white rice between the panes. The rice will absorb the moisture and dry the glass, like rice in a salt shaker. When it drys out you can clear silicon the hole shut. I have made sky lights with a small cloth bag of rice in it and they didn't fog. If you can get to the aluminum spacer seal on the edge you could drill through that instead and add rice. The worst case is the glass will break and you will need a new pane, if it works it will be as thermal efficent as a storm window, good luck

By Judy (Guest Post)12/03/2008

This happened to me. The first time I was under warranty (10 years) and the company replaced it. This time I'm not, and I will have to pay for a replacement. The seal has broken.

By Marie [27]12/02/2008

I had to replace mine when that happened.

By Shirley [1]12/02/2008

Use your blow dryer for your hair point it at the window and it should clear it right up

Shirley from Calif golden7673 AT

By Harry (Guest Post)12/02/2008

Fogging in a double pane window usually means there is a leak in the seal and moisture has gotten in between the two panes of glass. The glass pane has to be replaced.

By (Guest Post)12/01/2008

If this is insulated glass, the seal has failed. The way to tell if it's insulated glass is to look between the two panes where you'll see a spacer bar that is likely either aluminum or black. If you have a warranty that is still in effect for your windows check it to see how long you are covered for seal failure.

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