+1 skydawggy

absolutely normal, no cause for concern at all

I noticed the same thing after I got new windows and panicked but then saw it was on the outside, not between the panes. As the others here say, it is normal. Low-E coatings can make it worse: http://www.rlcengineering.com/win_cond.htm
In cases where the inside temperature is below the outside temperature, a Low-E coating will allow the outside glass temperature to drop to about the same as that of an inefficient window. In cases where the outside air is colder than the inside temperature, a Low-E coating allows the outside glass to get even colder. Therefore under the right conditions, windows with Low-E coatings can develop more summer condensation than inefficient windows.

Thank you all for the info, explaination, and website.

As you can see from my post I thought just the opposite: the temp diff between 2 panes of well insulated low E glass seperated by a layer of gas, air, whatever it is, wouldn't register. I get it now.

I ended up putting a call in to Home Depot before these responses, (dying to know) and the project manager told me he called the company and both agreed it's normal, but a little unusual here because of our mild climate. Also we have our thermostat set back to 60 degrees at night and I noticed the fogging before the heat kicked in so again, unusual.

Project manager added he's had a few customers call with the same question. Most had it happen a couple of times when first installed and then the fogging never happened again and a few had it repeatedly happen and they replaced the glass with no further problems. So we'll see what happens. Happy to know it's supposedly normal, but if reoccurs with little temp change or only rain they will replace. Hope that isn't necessary!

Thanks again!

What would they replace it with? The only thing that would prevent it from re-ocuring would be less efficient glass.

I'm a little confused by that too. Saying it's normal, but also saying others have only had fogging occur a couple of times when first installed and others had it repeatedly occuring and resolved when replaced with new window of the same is a bit of a condradiction. What was odd was the perfect symmetry of the fogged area, like a smaller perfectly cut frosted glass was layed over the center. Also odd that last night it poured rain was much cooler out and warmer in and no fogging. Beats me.

I have the same problem with my newly installed dual pane windows. It occurs mainly on all my west facing windows. I panicked when I saw this too and called the company who installed them. He had me speak with the sales rep in the area, who told me it was normal. I believe they should warn people about this. It is rather annoying not being able to see out any windows in the morning. It last for several hours too. I did not have this in my last house, but those windows were installed when the house was built and were not retrofit windows. They also were not low e. So, the low e might be the main problem.

Fogging on the outside of the glass is normal and actually means the window is working well by preventing the heat from the home from transferring to the outside surface.

Colder outside surface = dewpoint.

WoW +1

This will become more of a problem as triple pane windows become more popular. There are some folks entertaining putting a low- or mid-emmissivity coating on the outside surface to prevent (since this would prevent the glass from signicant radiant cooling that causes it to drop below the dew point). (I need a coating like this on my car windshields!).

Cardinal's new X89 coating was developed specifically for that application.

Like NEAT it is an "easy clean" surface 1 coating but with the intended added benefit of eliminating surface 1 condensation - basically morning or evening dew.

I wish I had it on my windshield as well!!

This post was edited by oberon on Fri, Mar 7, 14 at 17:01

What...you don't like ice scraping in the AM Oberon?

Try not to live in the tundra and see if that helps!!!

Ha! I am going to call you Ober-Popsicle from now on.

Two weeks ago my daughter is reading the forecast for the next week (actually last week) and she says "oh good, it's going to be above zero all next week, well except for in the morning when we go to work, it will still be below zero then".

Somehow at the time that still seemed like a positive forecast.

Yep, I am tired of scraping my windshield! I think we have well passed 50 days total below zero this winter and we have hit -20 or colder maybe 7 or 8 times. Not to mention the five or six feet of snow.

You know it's a real winter when you go outside wearing a sweatshirt (no hat or gloves) and you think "not bad at all kinda nice out", then you look and it's eight below zero.

For our Canadian and Euro friends, hat would be F and not C.

Kinda reminds me of winter when I was kid...and if you are bringing popscicles, I like root beer!

Did the window fogging ever stop? We have the dame story....from wisconsin and frusterated it is all sides of our home all fogged in a perfect little square with an inch of visible space all the way around it. Did Home Depot fix problem? And how?

"Did the window fogging ever stop?"

Only way to "fix" the fogging is to replace the glass or sash. The seal is broken and is not fixable.

Fogging is only an issue if it happens BETWEEN the glass and it doesnt ever go away.

condensation on the outside is normal !

+1. If the is on the outside of the glass, it is both normal and an indication of proper/superior functioning.

If it is between the panes, you will need to have the glass replaced and this will be clearly evident because the condensation does not go away with the change of the daily temperature.

Less than a month ago we had new windows installed in our home. We have noticed that with the cooler nights and some nights where it has rained we are getting fogged up windows ...On the outside! The first time it happened I reached out to the salesman, and he told me, that this was normal. It has now happened several more times. It starts at around 9 pm. and we cannot see outside. This fog stays on the windows all night, and does not dissipate until after 9 am in the morning. This is very disturbing and embarrassing when we have company over for the evening... and no one can see out to the deck. I find it hard to believe that this is normal. To me it is an indication that the windows are failing, whether from installation or the window itself. Living in the lower mainland of BC, where we get rainfall 70 percent of the year, I feel that I am being fed a line and that I have just wasted thousands of dollars on substandard windows. Has anyone had this issue with their new windows?

Also, with the last rain we had, we also found that on several windows there were thousands of water droplets left on the outside of the window. These water droplets took half the morning to disappear. Once the droplets disappeared, it left water marks behind. Not impressed... AT ALL.

The first 2 pictures attached are taken from the inside of the house, but the condensation, or fog is actually on the outside as shown in the last picture of the patio door. The other picture is all the water droplets after the rainfall.

In regards of this supposedly being normal.... why did the Salesman not be upfront about the behavior of the windows?? Why was I not made aware that fogging may be a possibility? To be told once the windows were installed, and I reported the issue , that this behavior in normal is unacceptable.

It can be a normal phenomena depending on the moisture and temperature conditions of the outside air. What kind of Low-e did you get in the patio door?

Hi;

The windows are double pane with argon gas low-E , u-factor .03 ; Solar Heat Gain Coefficient .34 ( this is taken off the window label ) All the windows were replaced, so am thinking that the low e is the same for each window? The fogging can happen on all the windows throughout the house and has. These pictures attached are of windows facing the front of the house ( opposite side from patio doors)

I have new windows. I had guests in this evening. As we were looking out onto the river I noticed my windowswindows were fogging up, just as you described. They got so bad I couldn't see out. The reason I purchased this house was the river view. I was mortified and embarrassed. I looked around at the other windows to discover, to my dismay, several others doing the same thing. Is there a way to prevent this from happening?

Hi; Any of the other homes along the river have the same issue? I have been asking several professionals in regards to this and they are surprised about the exterior of the window fogging up. Have you gone back to the window company and told them? I really don't think it is normal, as several other homes iin the area have had their windows done and they are not reporting any issues. What was the humidity in your home that night? I am still investigating... will update you on any info I get.

The only think you can do is make sure that the blinds in front of the window are open and that proper air is circulating in front of the window (i.e. interior side of the home). That will hopefully allow for enough radiant, convective, and conductive energy to migrate to the outer pane to keep it above dew point.

It is normal for a window that is higher efficiency and especially on North facing windows and high humidity.

Hi;

Thank you for the information.

However, in one of the pictures you can see that the window is open and it did not stop the window from fogging up and that window is facing West.

As with other windows throughout my house that had fog on them, some were open, others were closed. The fog was either on the outside of the closed pane or on both panes.

I have tried it both ways... closing the windows, and then leaving some open. Made no difference. Windows still fogged up.

I really feel it is the performance of the windows failing as other neighbors that had their windows replaced are not reporting this issue.

I know it is hard to keep all the variables the same, but it just seems very odd that I have to deal with this after a rain, or in some cases when there is a weather change.

I don't know how else to try and fix this.

Some nights, by 9 pm, we cannot even see out our windows, the east side windows being the worse for seeing out of.

I think that something is deficient in the installation or the window itself, because if this is a normal phenomenon then more people would have it. And if this is normal behavior of new windows, then this information should have been disclosed up front prior to the purchase.

Could it have anything to do with the humidity in the home itself? Being either too high or too low?

To Dalee 2. I understand your frustration. We had 8 windows installed with 2 facing west and 6 facing south, including a picture window. No fogging. Then we had the rest of the house done with 1 facing west and 2 facing north. Same windows but installed by two different subcontractors. The 2 north facing windows have fogged up from day one. On the exteriors. I was so upset because NONE of the other windows are fogging up. I asked the contractor and he does not really have an explanation. The rooms are empty right now because of remodeling. If they continue fogging up after carpet and furniture are installed I’m going to be very unhappy. I know by reading articles on the internet it is ”normal“ but not to me. I cannot look out the window in the mornings because of the condensation. I have several neighbors who had their windows replaced. I will ask them if they are having issues. Of course theirs may be different windows than ours.

I don’t know the solution other than demand the contractor replace those 2 north facing windows.

This is summertime, by the way. In the Texas heat.

Without any information on the windows and Low-e type and surface, its impossible to tell why one window will do it and another will not.

In response to HU-438494989 ; I too am very frustrated that I am being told this is normal. If it is normal then this information should have been provided prior to installation. And like you, I look at other homes in my neighborhood that have had their windows done, ( some by same manufacturer ) and I do not see the fogging happening in their windows. My windows face east and west. The fogging usually occurs after rain, however this morning there was fog on the windows and it did not rain yesterday. When I review information on the internet, all the information is provided by the window industry, and perceived as normal. What is normal about a high performance window not being able to keep the outside glass pane clear of fog? I am still investigating and am very unhappy with my windows. I believe that if I had gone with another manufacturer I would not have this problem. Could it be how much argon gas is between the panes? How the panes were sealed? It is a mystery.

I copied this from an old post. It offers some solutions as I think the cause is well chronicled and not any windows "fault". As to warning home owners, it only happens in a very small percentage of replacement situations. I have never witnessed an ongoing situation so it seems as if the "fogging" eventually ceases. Hope this helps:

Basically, exterior window condensation is dew. It's no different than the moisture (dew) that you might see on your car windows or on your lawn. Same mechanism at work.

Exterior condensation formation on window glass is dependent on a number of different environmental factors such as exterior temperature, overhangs, prevailing winds, plantings, even cloud cover (or lack of), so that it is entirely possible that some of the windows in a home can have condensation and others nothing. In fact it is entirely possible that one window in a mulled set can have exterior condensation while the adjacent window has none.

Your old single pane windows didn't have exterior condensation simply because you were heating the glass enough to keep the surface temperature above the dew point, whereas now the combination of dual pane and LowE coating on your new windows is preventing the warmth inside your home from warming the outer glass which results in cooler exterior surface temperatures and condensation when the conditions are right.

Since this is a major concern for you, you may be able to eliminate or at least minimize the exterior condensation by heating the windows directly with a space heater. This kind of defeats the purpose of installing more efficient windows, but if you can warm up the interior glass enough then some of that heat will transfer to the outer glass and will hopefully raise the temperature above the dew point eliminating the condensation.

Adding ducts below the window probably will have no effect on the exterior condensation because the IG unit will likely be able to block that additional (indirect) heat from passing thru to the outer lite.

You might also try cleaning your exterior glass with something like RainX. I don't know if that works or not, but some people have claimed that it helps.

Thank you East Bay 10. That is a very concise post and summarizes it nicely.