Foggy Window Repair (Fix Fogged Glass in Double Pane Windows)

In an older home, it’s not uncommon to see condensation in between the 2 panes of glass on some of the windows. New windows are expensive, so I wondered if it was possible to DIY double pane foggy window repair.

Double pane foggy window repair can be done by drilling 2 small holes on the outside pane of glass. As the sun hits the window, the trapped moisture & condensation get released. Then glue small plastic tubes in the holes to prevent further moisture from getting into the window. 

But that’s just a quick rundown of the process. So in this post, we’re diving in deep into glass window leaks and repairs.

We’ll examine the causes, preventative measures, and finally how to fix them. So if you have ever wondered can double pane windows be resealed? Read on.

Specifically, we’re going to go step-by-step on how to do double pane foggy window repair.

That way you can learn about defogging double pane windows and save yourself considerably on avoiding replacing those leaky windows.

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Can foggy double pane windows be repaired?

Foggy double pane windows can be repaired. It requires drilling 2 small holes which will allow the trapped moisture to evaporate during the heat of the day. Then once the fog clears, the holes get plugged.

Don’t worry. The step-by-step is down below.

You can, of course, get new windows which could be upwards of $1000 or more. Or you can find a repair company that can replace the double pane glass unit as a whole.

But trying to repair it yourself first is the best option if you’re on a budget.

You see, the way double pane windows work is with 2 panes of glass that are sealed. When that seal fails, that’s when condensation gets in. So some repair companies will simply slide the 2 pieces of sealed glass into your existing window frame.

Trouble is, that’s almost as expensive as a new window.

Particularly in humid areas where the climate changes are quite extreme, wooden window frames are usually to blame.

When too much moisture builds up in the wooden frames, the wood begins to rot, in time causing the window’s seal to fail. By the time fogginess has appeared between the panes of glass, this indicates that the window’s seal has been compromised, which lets moisture seep inside.

If rotted wood is the problem check out just how easy it is to Replace Rotten Wood on a Window (click to read my detailed article).

Once the seal is damaged on your thermal windows, it cannot be re-sealed. Usually at this point, replacing the windows is advisable, but it is very costly.

However, there is a chance you can do double pane window fogging repair by fixing it yourself. There is a chance you may crack the glass, in which case you’ll have to call a pro.

But there’s a chance you can fix it yourself and you could save a lot of money!

How do double pane windows work?

The way that double-pane windows, also known as thermal windows (or insulated glass unit or I.G.U.s) work is by providing an additional layer of insulation.

This additional level of insulation helps your home to maintain a consistent temperature by minimizing loss of energy and transfer of heat between the exterior and interior environment.

You’re probably going to find that, like most modern thermal-pane windows, your windows have two seals.

The inner seal is there to ward off excess moisture and prevent corrosion, and the outer seal enhances the durability of your window.

These seals will be holding a spacer in place, which is generally a tube that contains water-absorbent solutions.

How to remove haze from double pane windows

Haze trapped inside double-pane windows can be removed by utilizing a dehumidifier next to the window. Then drill 2 small holes on the outside of the window to allow the moisture to escape. Once clear, plug the holes and re-seal the broken seal that allowed the moisture in to begin with.

Double pane windows work by having 2 pieces of glass with space in between that is airtight thanks to window seals. That means, in theory, no moisture, dirt, etc can get in-between the pieces of glass.

Of course, all of us have seen, and probably had windows that looked foggy, hazy, or had condensation inside of the window; in between the 2 glass panes.

It’s frustrating of course, as you know you could clean it if you could just get between the 2 panes.

So what’s the solution if you don’t want to replace your windows or try the somewhat risky procedure I outline below?

That haze is trapped moisture. Most likely there is a big temperature difference between the inside of the house and the outside. That’s in addition to their being a break in the window’s seal somewhere.

Here are the specific steps you can take on how to remove haze from double pane windows:

  1. Use a dehumidifier placed next to the window on the inside of the house. This will slowly remove the excess moisture from in-between the 2 panes of glass.
  2. If the break in the window’s seal is obvious, and the window is now clean, you can simply fix the seal. Weatherproof silicone caulk is a great and inexpensive option for plugging the hole in the seal
  3. If you cannot see an obvious break in the seal, you can simply repeat the process with the dehumidifier as needed. Most likely you’ll notice it come back during extreme weather.
  4. If the window is actually dirty or streaked in-between the glass you’ll have to drill a hole in the window. Assuming you have a modern vinyl window, the bottom is the least conspicuous place to drill. Anytime you drill into a window, you run the risk of breaking the glass or damaging the window. But if you’re at this point, you’re simply trying to avoid replacing a window. So you don’t have much to lose as the alternative is replacing it.

Drill a hole small enough to fit between the 2 panes of glass. But large enough to insert a long pipe cleaner or other long, thin object that you push into the hole with fabric on the end. A coathanger works great.

Insert it in and wipe around until you remove the moisture.

You’ll want to seal the hole you drilled with silicone. But if there’s any trace of moisture, use a dehumidifier first to dry it out. Otherwise, you’ll trap the moisture in there.

Can you clean inside double pane windows?

To clean the inside between 2 panes of glass in a double-pane window, drill a small hole in the top or bottom of the window directly in between the panes. Then use a long pipe cleaner or coathanger wrapped in a thin layer of fabric and insert it into the hole to clean it.

So, the short answer is yes. But it’s not an easy thing to do.

Double pane windows are designed to work with 2 pieces of glass with an airtight seal between them. As long as that seal remains unbroken, you should never see dirt, moisture, or haze in between the 2 panes of glass.

If you do, that means the seal is broken somewhere, which is a common problem.

If the break in the seal is obvious, that’s good news. That means you can clean in between the glass and then fix the seal and the window should be as good as new.

If you can’t find where the seal is broken, then even if you clean in between the panes, it will eventually get dirty or hazy again later. So at that point, your choice is to either live with it or replace the window.

I detailed this in the above paragraph, but here’s how to clean inside double pane windows:

  1. Drill a small hole on the bottom of the window centered in between the 2 panes of glass
  2. Use a pipe cleaner or coathanger wrapped in a thin layer of fabric and insert into the hole
  3. Move the object around to clean the area that is dirty
  4. Once clean determine if there is still moisture remaining
  5. If yes, use a dehumidifier to remove the moisture
  6. But if there isn’t moisture, or after the moisture is gone, use silicone caulk to plug the hole you drilled
  7. If you can figure out where the original break in the seal is, use the caulk to fix that too

Why are my double pane windows cloudy?

Double pane windows get cloudy or foggy when the seal around the glass breaks or gets broken. A broken seal allows moisture to get in between the panes of glass and then depending on the outside temperature and humidity, the fogging can get worse over time.

On the whole, IGUs (insulated glass units) work really well.

They are able to withstand all sorts of weather, from freezing climates to sweltering heat and blustering winds. Because there are two seals, one can carry the weight of the other for a while, should one of these seals break or fail.

But, inevitably, the other seal will buckle under the pressure and will begin to deteriorate as well.

When that happens you’ll begin to see condensation inside your double pane windows. You may also experience heat loss as the warm air moves out and the moist air moves in.

If there is inadequate drainage, water starts to collect and spread, further damaging the seals and even jamming or rotting the frame (if it’s wooden).

Your windows also face constant direct exposure to the outer elements, particularly sunlight.

Temperature fluctuations cause the glass to continuously expand and contract. Over time, this warps the shape of the glass, causing it to fit improperly in its frame.

As the glass and the frame weaken over time, more air and moisture is able to seep in between the panes of glass, causing the build-up of moisture which you see in the form of condensation on your thermal panes.

How do you fix condensation on the inside of the windows?

To fix condensation on the inside of windows:

  1. Drill two tiny holes, on the lower side of the outer pane of glass.
  2. Allow time for the condensation to escape (how long depends on humidity, moisture, and temperature) – 2 weeks to 2 months
  3. Fill the holes with 1″ of clear plastic tubing
  4. Use caulk or glue to glue the tubing in place
  5. When the caulk or glue is dry, snip the excess tubing so the tub is flush with the window
  6. The cooler the temperature, the quicker you should see results as running your AC can create humidity and slow the process

Remember, you should only attempt defogging double pane windows if you are prepared to have the window replaced, this is not guaranteed.

Don’t pick a day to work on that is either very sunny or extremely cold. The additional strain on the glass could result in its shattering.

Also, remember safety; wear gloves and safety goggles as the glass could break.

How it works:

What happens is, when sunshine hits the window, the outer glass will warm-up, absorbing condensation inside double pane windows which is trapped.

Due to the fact that hot air is expanding, it should move toward and through these holes.

As it starts to cool down at night time, the cool air seeping in will be drier. In many cases, this procedure will gradually clear all of the moisture out of the window.

Want some tips on drilling holes in glass? Check out this video.

How to plug the holes you drilled (once the moisture is out)

First of all, whatever caused the condensation inside double pane windows in the first place has not been addressed. Most likely this is a broken window seal. So, new moisture can still creep in from the source.

So if you have rotting wooden window frames make sure to repair those too. Even replacing the entire window frame will still be cheaper than replacing the whole window.

Secondly, if rainwater gets into your new holes, then your window will end up worse than when you started. Bugs can also get into these tiny holes as well.

If you live in a climate that sees hot and humid summers, then you may want to consider performing your double pane foggy window repair during winter.

Otherwise, when you run the air conditioning, you may find the process working backward and that your windows fill up with water.

So once the condensation is cleared out, we need to fill the holes.

Place an inch of plastic tubing into the holes, which you can glue into place using clear silicone or caulk. The tubing should be the same size as the hole you drilled. Once the caulk is dry, just snip any excess tubing and caulk off of the repair spot.

Depending on the climate, the process can take anywhere from 2 weeks to 3 months to take effect.

The colder the temperature, the quicker you should see results.

If you would rather consider professional window security film to both cover the foggy windows but also provide benefits like UV protection, security from prying eyes, and reduced energy bills, check out one of my newer posts about whether or not Security Film is Worth It (click to read now on my site).

Can double pane windows be resealed?

Double pane windows can and should be resealed to prevent future moisture from creeping in, but only after removing the condensation inside first. First, remove the section of the old or worn gasket and then use silicone caulk to reseal the window.

IGUs have an added layer of protection from the weather that keeps your home more energy-efficient. As we mentioned above, 2 panes of glass are held in place with rubber gaskets, and gas is inserted between the panes.

As the gasket is exposed to rain and temperature extremes, the rubber can begin to fall apart. This allows excess moisture to sneak in between the two panes of glass.

So while you can follow the steps above to remove the condensation inside double pane windows, you will then possibly need to replace the gasket to keep the window in good shape.

After all, you don’t want to go through the steps of double pane window fogging repair only to have to do it again 6 months later!

If you are super handy, you can actually remove the old gasket, get new ones from a glass shop and install the new ones.

However, ultimately since we are DIYing this and not adding gas back in between the panes like a pro could, caulking is a much simpler solution.

Thus, run a small bead of clear caulk around the entire edge of the glass on both sides. Once dry, you can scrape off any excess with a razor blade.

defogging double pane windows and double pane window fogging broken glass in a window frame Middle Class Dad

How much does it cost to fix a double pane window?

Factoring in glass, labor, caulking, and repairing any damage to the window frame, a DIY window repair will range from $50 to $100 per window. A professional repair will be between $250-300 per window.

If your best DIY efforts fail and you need to call a pro, here’s what to expect.

Just replacing the glass? Glass repair companies, on average, charge about $3.00 per square foot of regular single pane glass. To fix a double pane window (which as we mentioned above contains gas in between the panes of glass) you’re looking at paying between $250-$300 per window.

Does home insurance cover foggy windows?

Most homeowners’ insurance policies do not cover foggy double pane windows. These policies are designed to cover damage to the home which could lower the value of the home or create a hazard.

Foggy double pane windows are just a nuisance. They are irritating, but they don’t present a danger to anyone. They also don’t significantly impact property values.

Also, if you consider that most of us have deductibles on our homeowner’s insurance of $2,000 or higher unless you needed to replace a bunch of windows, it probably wouldn’t be worth it for 1 or 2 windows.

So, unfortunately, don’t plan on filing a claim with your homeowner’s insurance.

If you recently bought a home and it came with a warranty like those offered by American Home Shield, those also do not typically cover things like foggy windows.

Why do double-pane window seals break?

Double-pane windows are a great way to save energy and money, but unfortunately, their seals can break over time. This can lead to fogging, condensation, and other issues that can make the windows less effective. So why do double-pane window seals break?

The most common cause of broken double-pane window seals is age.

Over time, the sealant used to keep the two panes of glass together can degrade and become brittle. This can cause the seal to crack or break, allowing air and moisture to enter between the panes of glass.

Another reason for broken double-pane window seals is improper installation.

If the sealant isn’t applied correctly or if there are gaps in the sealant, it can lead to air and moisture entering between the panes of glass. This can cause condensation and fogging on the inside of the window, which will eventually lead to a broken seal.

Finally, extreme temperature changes can also cause double-pane window seals to break.

When temperatures fluctuate rapidly from hot to cold or vice versa, it causes stress on the sealant which can eventually lead to cracking or breaking of the seal. This is especially true in areas with extreme weather conditions such as deserts or mountains where temperatures fluctuate drastically throughout the day.

In conclusion, double-pane window seals can break due to age, improper installation, and extreme temperature changes.

To prevent this from happening, it’s important to make sure that your windows are installed correctly and that you check them regularly for signs of wear and tear.

Additionally, if you live in an area with extreme weather conditions it’s important to take extra precautions such as using insulated curtains or blinds in order to reduce temperature fluctuations inside your home.

Are dual pane windows the same as double pane windows?

Dual-pane windows and double-paned windows are often used interchangeably, but they are not the same.

Dual pane windows are two panes of glass that are separated by a spacer. The spacer is filled with a desiccant material to absorb any moisture that may be present in the air between the two panes. Double pane windows, on the other hand, have two panes of glass that are separated by an air space.

This air space is filled with an inert gas such as argon or krypton to reduce heat transfer and improve insulation.

Dual pane windows offer superior insulation compared to single pane windows, as they reduce heat transfer and keep your home cooler in summer and warmer in winter.

They also help reduce noise from outside sources, making them ideal for homes located near busy roads or airports. Additionally, dual pane windows can help reduce condensation on the inside of your windowpanes due to their desiccant material which absorbs moisture from the air between the two panes.

Double pane windows offer similar benefits to dual pane windows but with improved insulation due to their inert gas filling.

The inert gas helps reduce heat transfer even further than dual pane windows, making them more energy efficient and helping you save money on your energy bills over time. Double pane windows also provide better soundproofing than dual pane windows due to their thicker air space between the two panes of glass.

Overall, both dual and double pane windows offer great benefits when it comes to insulation and soundproofing for your home.

However, double pane windows provide superior insulation due to their inert gas filling which helps reduce heat transfer even further than dual pane windows do. Therefore, if you’re looking for maximum energy efficiency and soundproofing for your home then double pane windows may be the best option for you.


In this post, we walked through identifying the underlying causes that led to the condensation inside double pane windows.

We also looked at the steps that anyone can take to DIY defogging double pane windows. He also pointed out the risks involved and when to admit it’s time to hire a professional.

But most importantly we learned how to get condensation out of windows, and you now know that double pane window fogging repair is possible to do ourselves!

If you have condensation inside double pane windows have you tried fixing them?

Before fixing those windows fogging up in the house, make sure you have all the proper tools.

For DIYers, check out my Recommended Tools page (click to see on my site). I know my page will save you both time and money, and I only list the best of the best either what I personally own or have used, or the top reviewed items on Amazon.

I also list the best, and oftentimes, that’s NOT the most expensive item too.

About the co-author of this post.

Alex works for Apex Window Werks which is a home window repair & replacement company which also specializes in foggy window repair. They provide their services in the following states: Illinois, Wisconsin, New York, Colorado, and Ohio. Feel free to visit their website for more details. Follow them on Twitter or Facebook for more great tips!

Of course, because of the society we live in, I have to add the disclaimer that by allowing this post, I am not necessarily endorsing the steps outlined in the post nor do I offer any guarantees of the suggested work. The opinions expressed belong solely to Alex and Apex Window Werks. If you have questions, feel free to comment and I’ll do my best to answer, but you may also wish to contact Alex directly at

Photo credits which require attribution:

Innerglass-low-e-illustrati.jpg by Maghriby2660 is licensed under CC4.0

Jeff Campbell

16 thoughts on “Foggy Window Repair (Fix Fogged Glass in Double Pane Windows)”

  1. I agree with Mark!!! I’ve been in the glass industry for 40 yrs and this is the dumbest thing a home owner should ever attempt to do. I can’t believe anyone would recommend something like this. Dangerous and totally irresponsible! I cannot stress this enough..
    They cannot be repaired and must only be replaced! And that’s the sorry truth of the matter!
    P.S. And if you try to do this on a door………..stand back for a big surprise!!

    • If replacing is the only option, then there’s no harm in trying it as in the worst-case scenario, you just replace it anyway. But if it works, which it will for many, that can save a lot of $$. I get that as a pro, you feel like this article/technique cuts into your livelihood, but your argument should at least make sense. And I’m sorry, it just doesn’t.

  2. If you’re going to try this and are not experienced with a power drill and a glass drilling bit (diamond), you may want to avoid doing this until you can afford to replace the glass. If the window shatters, you will have to replace it whether you can afford to or not. Being a professional handyman for many years, I have been asked to perform this repair, but have turned the job down because it’s just not a good solution and the customer will eventually be unhappy with it. It’s a “Band-Aid” repair. Learn to live with it until you can afford to replace the glass.

    • Hi Greg

      Good points. I think it depends on how bad it is, but I think it says a few times in the post that anytime you drill into glass, breaking it is a possibility. But for many, knowing that risk, they don’t really have much to lose by trying it. After all, for many, it will work, and can save them a lot of money.

      But definitely some good points. Thanks for taking the time to comment.


  3. Jeff, Why not drill one hole at the bottom and one at the top. Since heated air will rise, you would create a flow of cooler air coming in the bottom hole, getting heated, and rising up and absorbing moisture as it exits thru the top hole. I would think that would clear the moisture much quicker.

    • Hi Bob

      Great question. The only reason I can think of is the minor risk involved of shattering the glass when drilling. Doing that twice obviously doubles that risk. But I think if someone is confident with doing that it could be even better than the 1 hole.

      Thanks for commenting!


  4. I had my window panes done by a specialist for this problem. he washed in between the panes now I have water streeks. can I call the specialist and ask him to wash them again??? The reason I called him the first place because they were cloudy. barely cloudy but now looks worse than before.

    Hope you have answer for this problem.

    • Hi Josie

      Thanks commenting. I can’t imagine why he did that as it sure seems like that would indeed lead to streaks inside that would be hard to get rid of. The only thing I can think of (assuming he knew what he was doing) was that maybe there was something beyond condensation that needed to be washed away?

      But at any rate, yes, I would definitely call him back to fix it.

      Thanks for being here and let me know what he does to fix it. I would think, assuming the streaks dried, he would have to spray again and then use a heat source to dry it quickly so it doesn’t streak, but I’m really not sure.


  5. If it’s a window which opens, why not drill in between the panes from the bottom or top (or sides, for that matter) and avoid the risk of breaking the glass?
    I’ve got elderly plastic double glazing and one window actually has water collecting in the bottom.

    • Hi Luke

      Great suggestion! Drilling from the top or bottom could obviously be done without removing the window (like the sides). The bottom might be the least conspicuous place to do it. The only thing I’m not sure about is if the condensation would evaporate as quickly as it would with the hole in the glass since the glass getting warmed by the sun is what facilitates that. But it sure couldn’t hurt to try and a hairdryer over the hole might fix that issue.

      Great suggestion. Thanks for being here!


  6. a simple question, why not drill the holes on the inside of the glass where there would be less insects and dust issues? my fogged window is a full glass door on a semi heated porch.

    • Hi Belinda

      I think in Alex’s mind (Alex was the author of this post) the window would be getting sunlight on the outside and so it made sense to drill it on the outside where the heat would cause the moisture to evaporate. In most cases, the inside would be getting potentially cold, moist air from an air conditioner (at least in some states) which could be problematic.

      But what you’re describing probably should work just fine. If you find it doesn’t get rid of the moisture and condensation fully a dehumidifier could help too, but that’s new territory for me.

      Hope that helps and thanks for being here!


  7. What a load of crap ! From what I can make out,this is nothing more than an advert for window film from Amazon . Being retired now from the glazing industry,where I served my time as an apprentice glazier and spent a further 25yrs in this job, take it from me, when the seals go on your ‘double glazed’ units, they cannot be repaired, replacement is your only option, trying to drill holes in glass without the specialist equipment and without having the unit lay flat, putting a drill anywhere near glass will only lead to the glass cracking and needing to be replaced at best, at worst, it’ll lead to you putting your hand through the glass causing a very nasty cut !
    ‘Double pane window’ ? If you’re going to pretend you’re in the glazing industry,at least use the correct terminology , which is a double glazed unit !

    • Hi Mark

      I can appreciate a difference of opinion, although I’ve always felt like name-calling or ridiculing those with a different opinion is what people do when they can’t make an intelligent argument.

      At any rate, as you know if you read through the article, the post was written by one of the owners of Apex Window Werks in Chicago, so he does know a little something about windows, window repair, and double-pane windows in general.

      I don’t know Alex personally as he, like a lot of people, approached me about writing a post on my blog about windows and I agreed. But I see from their 4ish star Google and Yelp reviews that enough people are happy with them that I doubt very seriously they make their money by providing bad service or information.

      The mention of the Amazon window film was added by me (not Alex) as an attempt to cover the expenses of running a blog. You may be opposed to people making money, but that is a very common way for most websites to generate income and as long as it’s a quality product I’m recommending (which it is), I don’t see anything wrong with it. If you do, then don’t buy it; pretty simple.

      Again, I do appreciate your taking the time to comment, even if you were rude. I also appreciate you obviously make money selling windows, which naturally could make you opposed to the idea of repairing them since that affects your livelihood. But I stand by the information Alex wrote and I’ve talked with people who have read this post and tried the process with success.

      I doubt very seriously if you did anything buy glance at the post and fire off an angry comment.

      I’ll lastly end simply by saying that Alex does indeed mention in the article that repairs like this are risky and don’t always work, but if you’re otherwise going to have to replace them anyway, why not try this first since it would save people a lot of money?

      But I still thank you for being here. I’m happy for you to comment back, but only if you avoid being rude as otherwise it will just be deleted; no one has time for rude people, especially me.


  8. This seems not too bad. I just hope i dont break the glass! Yes, your instructions where very clear to me. Wish me luck

    • Thanks, Christine!

      There is definitely some risk involved, but by going slow with the right drill bit, you can definitely do it! Comment back and let me kn9ow how it went!




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