Thread: Condensation - Is it Normal?

Recently had a contractor tell me that condensation that was running down the window and pooling on the sill was normal for the area (FL) due to a rapid temperature change. He also said there was a lot of moisture in the home from construction. The house has been occupied for a month and the HVAC system has the dehumidify setting on for that period. The inside humidity is around 47% and the outside temp was in the 40's at the time. He also produced a brochure from PGG stating that condensation was normal. I'm from the North and know what consolidation is, but with double pane windows I feel this is excessive. This window set, bedroom, was the only windows that had the condensation in pools. The other windows had small 1" strips on the bottom of the glass---nothing to be alarmed about. What do you think?

Yes, with what you say I agree with what the builder says. Windows will be the coldest point in any room and be the natural condensate point. The temps and humidity you give says water on the windows. Right now they are serving as a de-humidifier.

On less expensive windows the more condensation that can be expected. On windows that are an exception within the same house, I would look for damaged or missing weather strip at the bottom and parting rails of the sashes. On new construction I often see the bottom of the vinyl window sill damaged by drywall being drug through the window, usually on the second floor, then the window doesn't seal at the bottom.

Your bedroom might have more condensation because 1) you, your wife, maybe the dog too, breath a lot at night, and your breath is warm and damp. 2) You keep the bedroom on the cool side with the blinds down, so the glass is cool, below the dew point,

I say might, because there could be a problem or it could just be a lifestyles issue. Leave an overhead fan on and prop the blinds out away from the glass so the glass can warm up.

Originally Posted by John Kogel

Your bedroom might have more condensation because 1) you, your wife, maybe the dog too, breath a lot at night, and your breath is warm and damp. 2) You keep the bedroom on the cool side with the blinds down, so the glass is cool, below the dew point,

I say might, because there could be a problem or it could just be a lifestyles issue. Leave an overhead fan on and prop the blinds out away from the glass so the glass can warm up.

We have an overhead fan that is usually on, it was on that night. The door was open to the rest of the house and the HVAC was set for continuous fan. With both in operation one would therefore assume that sufficient air changes exist within the area.

Remember, we are from the north and have dealt with condensation all of our lives. But this was like a river coming down the windows. Have only seen this in single pane windows, not double pane.

I could agree with some of the comments except for this. The windows are double pane, the blinds were halfway up, and the other windows did not show this degree of moisture--just a small smidgin on the base of the window glass. These were the only windows on that side of the house. The Lani sliding doors on that side of the house did not show anything (the Lani outer screened wall is apx. 8' from the door). Forgot... no dog.

Inside humidity (47%) is too high. Get it down to the low 30's.

Originally Posted by Ken Rowe

Inside humidity (47%) is too high. Get it down to the low 30's.

OK will try. Thanks.

Originally Posted by Rich Goeken

We have an overhead fan that is usually on, it was on that night. The door was open to the rest of the house and the HVAC was set for continuous fan. With both in operation one would therefore assume that sufficient air changes exist within the area.

Remember, we are from the north and have dealt with condensation all of our lives. But this was like a river coming down the windows. Have only seen this in single pane windows, not double pane.

I could agree with some of the comments except for this. The windows are double pane, the blinds were halfway up, and the other windows did not show this degree of moisture--just a small smidgin on the base of the window glass. These were the only windows on that side of the house. The Lani sliding doors on that side of the house did not show anything (the Lani outer screened wall is apx. 8' from the door). Forgot... no dog.

As this only happened at these windows I would take some temperature readings at and around the windows. There may be an air leak or the window rough openings may not have been filled with insulation at these windows. In any case, there is a reason that this is only happening on two windows in the entire house. The inside of the windows in question are colder than any of the other windows or doors. Why?

Originally Posted by Vern Heiler

As this only happened at these windows I would take some temperature readings at and around the windows. There may be an air leak or the window rough openings may not have been filled with insulation at these windows. In any case, there is a reason that this is only happening on two windows in the entire house. The inside of the windows in question are colder than any of the other windows or doors. Why?

I forgot.... I can whip out my IR gun and check. Thanks for the suggestion.

Given you've counted out the usual reasons for dripping windows, and you don't have a big sweaty dog sleeping in the room, , yes, there might be a problem with those windows. Could there be a cold wind against that side of the house?

I would think 47% humidity is not overly humid. That would be dry air in my climate.

47% is not high in Florida this time of year when you don't have your A/C on much. I just glanced at my indoor humidity and its 53%. This is not MN. Where your gas furnace dries the air out to the point of static and humidifiers. Kinda cool here today at 60 degrees

Originally Posted by John Kogel

I would think 47% humidity is not overly humid. That would be dry air in my climate.

47% is where it should be in this (Florida) climate - 45%-55% 'feels good'.

I've had some houses where the thermidistat took the humidity down into the 30%-35% range and the people complained about it being too dry and drying out their skin. Took many calls to the HVAC contractor (which kept saying there was no problem - it was working like it should work), who finally broke down at my insistence and brought the factory representative in and within 5 minutes of walking in, before he even made it to the thermidistat, he said the humidity level is too low, that either the thermidistat was set to low or there was a problem with it ... a few checks and he said to replace the thermidistat, that he has some in his vehicle as they have had a few problems with the new systems (the thermidistat was a new introduction) and with that the problem was solved. You could feel the difference within a couple of hours (he came back after lunch and after addressing some other issues on some other houses I had).

Really is a pain in the butt when the contractor thinks they know it all and refuses to bring in the factory rep. A few times I had to call the factory, who sent their rep in to check it out and the rep dragged the contractor in against their will. The rep started bad mouthing the contractor in front of everyone telling the contractor that it does not cost the contractor anything to have him (the rep) come in and solve problems. I talked to the rep at the end of the day and he was fed up with that contractor but could not do anything about it because the contractor was one of their biggest customers in that area.

One big thing that seems to have been glossed over (except by the contractor) is the rapid change in weather.
We get this here (Texas) occasionally when we have a cold front move through (what we call a "Blue Norther".)
When we have a high humidity and warmer weather during fall/winter that has hung around for a few days and then have a front move through that rapidly drops the temperature by 30 degrees or so then condensation will form on every cool surface in the house.
The cooler the surface, the more condensation.
The R/H in the air may not be that high once one is trying to take temperatures and humidity readings since water that has condensed out on windows, etc. is no longer in the air contributing to the humidity load and the moisture content of the air typically is dropping like a rock trying to equalize with the outdoor humidity level.
The more air tight a structure, the more this issue will show up and hang around.

A quick way to remedy this is if the outdoor temp is substantially lower than indoor is to simply open a few windows slightly to flush the moisture out of the house.


Of course also exhaust fans in bathrooms, kitchens, etc. should be used to control moisture at all times but are not much use when the whole house is overwhelmed during weather changes.

Originally Posted by Paul Kondzich

47% is not high in Florida this time of year when you don't have your A/C on much. I just glanced at my indoor humidity and its 53%. This is not MN. Where your gas furnace dries the air out to the point of static and humidifiers. Kinda cool here today at 60 degrees

47% is not high in Florida when the outside temp is 75 degrees. When the temperature drops you need to lower the indoor humidity to prevent condensation from forming. The OP stated the outdoor temp was in the 40's (most likely running the heat) therefore his indoor humidity level should be set to about 35.

Since you guys in Florida don't have much experience when it comes to humidity levels in cold weather here's some good information for you. Home Energy Resource MN: Humidity

Originally Posted by Ken Rowe

47% is not high in Florida when the outside temp is 75 degrees. When the temperature drops you need to lower the indoor humidity to prevent condensation from forming. The OP stated the outdoor temp was in the 40's (most likely running the heat) therefore his indoor humidity level should be set to about 35.

The new electronic do-hickey (Carrier Edge TP-PRH) that is controlling everything except putting out the cat at night (no cat---just kidding ) only goes down to 46%. It's got it down to that area right now due to constant fan. Nice unit though, although based upon some comments from the folks up North, may not go low enough for their areas. Place to look if you have issues with humidity. Although the unit is set for heat at 60 degrees, based upon inside temperature at the time of the issue, I don't thing the heat came on. The house is insulated enough that it doesn't track with outside temperature changes too rapidly.

........most likely have a master bath within this bedroom? Could simply be excessive humidity within this space due to that?........Greg

Originally Posted by Mike Lamb

Yes, with what you say I agree with what the builder says. Windows will be the coldest point in any room and be the natural condensate point. The temps and humidity you give says water on the windows. Right now they are serving as a de-humidifier.

Barring defective windows I'd still agree with the builder. New construction will off-gas a lot of moisture and cold windows will create an even higher relative humidity at the window surface than in the middle of the room; that and showering, cooking, breathing, living, etc. I will assume no crawlspace or basement. If there is, that ups the moisture ante.

I don't believe Rich mentioned but the problem windows probably face the north.

Originally Posted by Ken Rowe

47% is not high in Florida when the outside temp is 75 degrees. When the temperature drops you need to lower the indoor humidity to prevent condensation from forming. The OP stated the outdoor temp was in the 40's (most likely running the heat) therefore his indoor humidity level should be set to about 35.

Since you guys in Florida don't have much experience when it comes to humidity levels in cold weather here's some good information for you. Home Energy Resource MN: Humidity

Happy New Year Ken, I don't live in Florida but the first 20 years of my life was at the 45th parallel, 1500 feet above sea level, where the snow didn't crunch but squeeked when you walked out in the morning. When it stayed cold the indoor humidity went down so much that your lips cracked and your eye lids felt like sandpaper. 50% RH felt good and most people used humidifiers to try to get there. Heating ducts were placed below windows or in the ceiling with the louvers pointing the air at the window to prevent condensation. In my opinion that was a better solution to the problem than bone dry air.

Originally Posted by Vern Heiler

Happy New Year Ken, I don't live in Florida but the first 20 years of my life was at the 45th parallel, 1500 feet above sea level, where the snow didn't crunch but squeeked when you walked out in the morning. When it stayed cold the indoor humidity went down so much that your lips cracked and your eye lids felt like sandpaper. 50% RH felt good and most people used humidifiers to try to get there. Heating ducts were placed below windows or in the ceiling with the louvers pointing the air at the window to prevent condensation. In my opinion that was a better solution to the problem than bone dry air.

While 50% might feel good, it's not good for the interior of the house when the temperature drops.
Please read the links I'm supplying. http://www.homeenergyresourcemn.org/...2991&pRID=2990

Originally Posted by Ken Rowe

While 50% might feel good, it's not good for the interior of the house when the temperature drops.
Please read the links I'm supplying. http://www.homeenergyresourcemn.org/...2991&pRID=2990

Ken, am I reading it wrong or does the chart on pg.9 show that a standard double pane window should tolerate 65% RH at 45 deg. F?

1. Are exhaust fans being run during showering and at least for 20 minutes post showering?
2. Are exhaust fans actually working and expelling exhaust to exterior?
3. Is the dryer vented properly?
4. Exhaust hood over stove being run during boiling water, et ceteras?
5. Plants and aquariums can release moisture into interior.

I didn't read how the house is heated? Furnace? Electric furnace or electric baseboards?

Originally Posted by Raymond Wand

1. Are exhaust fans being run during showering and at least for 20 minutes post showering?
2. Are exhaust fans actually working and expelling exhaust to exterior?
3. Is the dryer vented properly?
4. Exhaust hood over stove being run during boiling water, et ceteras?
5. Plants and aquariums can release moisture into interior.

I didn't read how the house is heated? Furnace? Electric furnace or electric baseboards?

Why only two windows?

Good question. Northside, northeast, northwest side of house? Not susceptible to sun, always in shade?

Originally Posted by Raymond Wand

Good question. Northside, northeast, northwest side of house? Not susceptible to sun, always in shade?

This sounds like a defective window. This window seems to be acting like a single pane window, the gas has leaked out between the panes of glass. This is what happens with a cold glass of water in a hot humid room. Its going to sweat.

Originally Posted by Raymond Wand

1. Are exhaust fans being run during showering and at least for 20 minutes post showering?
2. Are exhaust fans actually working and expelling exhaust to exterior?
3. Is the dryer vented properly?
4. Exhaust hood over stove being run during boiling water, et ceteras?
5. Plants and aquariums can release moisture into interior.

I didn't read how the house is heated? Furnace? Electric furnace or electric baseboards?

Does anybody run their exhaust fan for 20 minutes after they're done with a shower?

Adding to your list, is the furnace equipped with a humidifier, and what is it set at?

Twenty minutes is the recommend length to run the exhaust, and its not uncommon to see timers on the exhaust fan switch.

Originally Posted by Vern Heiler

Ken, am I reading it wrong or does the chart on pg.9 show that a standard double pane window should tolerate 65% RH at 45 deg. F?

Don't just look at the pictures, actually read the accompanying information:

This graph shows condensation potential on the center of glass area (the area at least 2.5" from the frame/glass edge) at various outdoor temperature and indoor relative humidity conditions. Condensation can occur at any points that fall on or above the curves. Note that the thermal conductivity at the edge of a window is general higher than at the center of the glass. For example, insulated glass with a low-e coating and argon gas may tolerate 61 percent humidity at 0 degrees, but the edge may show signs of condensation at only 26 percent humidity. When buying new windows, look for a low "U" value, and buy an ENERGY STAR window.

Then re-read the original post...

This window set, bedroom, was the only windows that had the condensation in pools. The other windows had small 1" strips on the bottom of the glass-

Originally Posted by Ken Rowe

While 50% might feel good, it's not good for the interior of the house when the temperature drops.
Please read the links I'm supplying. http://www.homeenergyresourcemn.org/...2991&pRID=2990

Ken
Those are some good informative links, thanks.

I deal with a lot of moisture issues; mainly leaks from construction defects but condensive moisture comes up when it's cold.
Jim hit upon one of the potential issues. When a cold front comes in and the house is at a certain level of humidity, let's use 55% at 70° for example both inside and outside.
If the exterior temperatures drop somewhat rapidly and the interior air does not adjust humidity wise then as the glass cools from exterior influence a microscopic climate with cooler air develops at the interior face of the glass. As noted in one reply in the north with forced air a vent is placed under the window to defrost the glass and help keep it clear. The same thing could be accomplished with a fan blowing on the glass surface and warming it closer to interior temperatures.
Back to my microscopic climate. As the air cools at the interior face of the glass due to exterior influence the humidity in that air increases. With a 20° drop the humidity roughly doubles so we now had 110% air and that is not possible. The temp drop at the glass forces the air to give up its excess moisture and condensation forms. Same thing happens when you take that cold can of pop out and expose it to warm air.
Everyone wants to have their homes absolutely comfortable and have the humidity just perfect. I have seen personal preference of 55% RH here in Iowa in the wintertime and it can definitely do some real damage. I had one home where the indoor humidity was at this level in the winter. The vapor drive is outward. The roof was spray foamed, the condensation point was at the roof sheathing and the rot that ensued was a real sight to behold.
Repairing a Rotting Roof - JLC Online Page 1 of 2
I often tell people up here to drop the humidity, use lotion, and put Vaseline up your nose. At least your house, your most expensive investment will survive.

Originally Posted by Ken Rowe

Don't just look at the pictures, actually read the accompanying information: Condensation can occur at any points that fall on or above the curves.

Then re-read the original post...
This window set, bedroom, was the only windows that had the condensation in pools. The other windows had small 1" strips on the bottom of the glass-

"Condensation can occur at any points that fall on or above the curves."

So anything below the curve, say 50% Rh or 50 deg. outside temp or 50% RH and 30 deg. outside temp, should not have a problem.

"This window set, bedroom, was the only windows that had the condensation in pools. The other windows had small 1" strips on the bottom of the glass-"

Does Mark's micro climate only occur at the bottom of the windows or is this where the glass is colder due to an air leak?

I did not find where it stated that the RH should be dropped to 30% with outside temps in the mid 40's. The chart shows that the standard double pane is good down to 0 deg. at 40% RH?

Originally Posted by Raymond Wand

Twenty minutes is the recommend length to run the exhaust, and its not uncommon to see timers on the exhaust fan switch.

Oh, I'm sure it's recommended. My question was how many really do this. I know I don't. That thing gets turned off as soon as I'm out of the shower, and am not seeing any condensation on the mirrors.

I know in my own home my double pane window fogs up in the bathroom when I shower in winter months. Even with the exhaust fan running.

Originally Posted by Vern Heiler

"Condensation can occur at any points that fall on or above the curves."

So anything below the curve, say 50% Rh or 50 deg. outside temp or 50% RH and 30 deg. outside temp, should not have a problem.

"This window set, bedroom, was the only windows that had the condensation in pools. The other windows had small 1" strips on the bottom of the glass-"

Does Mark's micro climate only occur at the bottom of the windows or is this where the glass is colder due to an air leak?

I did not find where it stated that the RH should be dropped to 30% with outside temps in the mid 40's. The chart shows that the standard double pane is good down to 0 deg. at 40% RH?

I've posted a couple documents which you seemed to have looked at the pictures, but not read. I quoted the paragraph describing the chart you looked at, but you apparently didn't read what I've posted. You have to read the entire paragraph, in fact, you had to remove that part of the paragraph when you quoted me:

This graph shows condensation potential on the center of glass area (the area at least 2.5" from the frame/glass edge) at various outdoor temperature and indoor relative humidity conditions.Condensation can occur at any points that fall on or above the curves. Note that the thermal conductivity at the edge of a window is general higher than at the center of the glass. For example, insulated glass with a low-e coating and argon gas may tolerate 61 percent humidity at 0 degrees, but the edge may show signs of condensation at only 26 percent humidity. When buying new windows, look for a low "U" value, and buy an ENERGY STAR window.

I deal with condensation issues 6 months out of the year and you still don't believe me. There's nothing more I can do for you.

Originally Posted by Ken Rowe

I've posted a couple documents which you seemed to have looked at the pictures, but not read. I quoted the paragraph describing the chart you looked at, but you apparently didn't read what I've posted. You have to read the entire paragraph, in fact, you had to remove that part of the paragraph when you quoted me:



I deal with condensation issues 6 months out of the year and you still don't believe me. There's nothing more I can do for you.

The problem is; I did read the documents. Both doc's have spec's that you are ignoring. The first doc. suggest lowering the humidity to no higher than 30% when the temp is 15 degrees. It also has a non-linear chart that stops at 40 degrees outside temp and suggest not over 40% RH. The op was in the mid 40's and had 47% RH. In a non-linear curve the condensation should not be as extensive as pictured.

You are not doing this for me, you are making a case for the contractor that says this is normal and it is the OP's life style that is causing only two windows to flow like rivers rather than looking for other reasons.

It is normal for a house to 'dry out' if its new construction. Having read article that allude to that point I don't think the contractor should necessarily be faulted for stating that. As to the drying out and geographic location I cannot comment that may change the equation since I reside in a northern climate.

Originally Posted by Vern Heiler

You are not doing this for me, you are making a case for the contractor that says this is normal and it is the OP's life style that is causing only two windows to flow like rivers rather than looking for other reasons.

Vern, you can't automatically blame the builder or look for random other reasons without addressing the interior humidity levels first. Lower the interior humidity first, and see what happens. It doesn't cost anybody anything. Yes, it could be the OP's lifestyle causing this and it may need to change. I shouldn't have to explain to you that new construction is tighter than old construction, less air exchange from inside to outside. If the OP isn't used to living in new construction he may need to change his lifestyle to maintain a healthy home. That change could be very simple, like running the bath exhaust fan for an hour after taking a shower, or setting the humidistat to a lower level when the outside temperature drops, maybe even adjusting the setting on the air exchanger. Things he may not have had in his old home.

Rich,
How are the windows doing today? FL looking way cooler than normal, more like the north. And your heat has been on for a while.

Ken; I am not playing the blame game but rather calling for further investigation. The condition as explained surely calls for it.

Two windows on the same side of the house as a patio door are the only ones sweating like a call girl in church. There is no supporting evidence that 47% humidity is too high and is the only cause for this to happen. True, the condition can be made to go away if you lower the RH enough, but would you have the caster and camber changed on your car's alignment or would you check the air pressures first?

You win Vern. There is no way that high humidity levels in a home in Florida can cause condensation on the windows. It never gets that cold in Florida. It must be the builder's fault.

Originally Posted by Garry Sorrells

Rich,
How are the windows doing today? FL looking way cooler than normal, more like the north. And your heat has been on for a while.

It was a littler cooler today Garry.

Ran a test this morning. The setup was as follows. The blinds pulled to the top. The ceiling fan on low. House temperature around 66-67 degrees, humidity around 47%. Outside temperature in the low 40's. The wife decided she was going to sleep in the other bedroom during the testing. Did find out the windows face North.

At 2 AM the center of the glass area in all windows (three windows separated with two metal jams) was around 57 degrees with a slightly higher temperature at the edges of around 58 degrees. The metal jams, however, were 10 degrees less at 47-48 degrees. The jams also had stickers that said that to remove the stickers would void the warranty. That is an interesting concept.

As for condensation, there was none on the windows, but the jams were sweating profusely.

Around 7 AM I lowered the blinds 1/4 of the way from the top so that most of the upper window pane was covered. After a period of time condensation did start to form on the window.

So, it appears the builder may be right in this case, but with exceptions. The exceptions are the jams and some colder areas around the window frames suggesting air movement. I need to check on the jams to see why they appear to be so important (stickers), yet do nothing to prevent heat or cold intrusion.

Thanks for all the comments. The discussions and information have been interesting and also helpful.

Originally Posted by Rich Goeken

Recently had a contractor tell me that condensation that was running down the window and pooling on the sill was normal for the area (FL) due to a rapid temperature change. He also said there was a lot of moisture in the home from construction. The house has been occupied for a month and the HVAC system has the dehumidify setting on for that period. The inside humidity is around 47% and the outside temp was in the 40's at the time. He also produced a brochure from PGG stating that condensation was normal. I'm from the North and know what consolidation is, but with double pane windows I feel this is excessive. This window set, bedroom, was the only windows that had the condensation in pools. The other windows had small 1" strips on the bottom of the glass---nothing to be alarmed about. What do you think?

I would run the air conditioning in the winter to get rid of the moisture. A fan running or the fan on the air handler constantly running is doing nothing but blowing the same damp air around the home.

Any gas in the home and a poor flue. A lot of moisture from that amongst other things. Rnning the exhaust fan every time you use the baths. If you don't where do you think all that moisture is going. Winter time evaporating water in toilets and traps and such into the home and then the warm air from the heater just blows it around. I don't know how old the Heat pump or AC unit is but anything in the past 10 years give or take should be able to run in the mid to upper 20s.

Dehumidifiers only dry you out along with the home and then you have respiratory problems.

Forget about all that for s moment and think a window problem that needs correcting. There is a ton of rreasons to have moisture in your home and that is easy to resolve if it is from normal typical causes. A window problem could be causing a whole lot of unseen problem.

Rich,

You mentioned metal jamb between the windows. Are these actually metal frames or metal jamb liners? Metal has little / no insulating factor and if these protrude continuously to the exterior you will always have problems with them during cold weather.

If this metal extends continuously to the exterior there is no way they would meet current building requirements here in MN and are most likely designed for warm climates. Not a problem with the windows or the installation, just not designed for the uncommonly cool weather you've been experiencing. Lowering the interior humidity levels will help, but not completely solve the problem.

Originally Posted by Ken Rowe

Rich,

You mentioned metal jamb between the windows. Are these actually metal frames or metal jamb liners? Metal has little / no insulating factor and if these protrude continuously to the exterior you will always have problems with them during cold weather.

If this metal extends continuously to the exterior there is no way they would meet current building requirements here in MN and are most likely designed for warm climates. Not a problem with the windows or the installation, just not designed for the uncommonly cool weather you've been experiencing. Lowering the interior humidity levels will help, but not completely solve the problem.

Not quite sure what you would call them (window guys---help me out), I called them "jams' and they appear to be ether installed in a rough metal frame the holds the windows or a piece part installed as a separator to fasten each window to in the 3-window set.

As they made a big thing of how energy efficient the windows are, I assumed they contain thermal brakes, especially with the sticker warning me not to take it off. But, it appears, from testing, this is not so.

Today it is PGG's turn in the bucket concerning these "jams." I could live with the windows as the testing for the last two nights show, even though this is a North facing window, if I maintain some type of airflow, fan, gravity, etc. and don't close the blinds all the way, they will not steam up. However, the jams weep like a sieve. The surface seems to be about 8 to 10 degrees above outside air.

The only saving grace is with the HVAC system set to dehumidify and with constant fan, we are around 40% humidity. Will post my discussion with PGG about the jams.

Rich,

Those metal pieces are "mulls", which is short for "mulluion" (spelling?).

They are metal (aluminum) through and through. They are the structural pieces which give structural support for the impact rating of the windows.

Not really much - if anything - can be done to those mulls, except maybe to sleeve them with PVC at the time of manufacture, but that would affect the window size and probably not really do much good regarding making a thermal break.

I think you explained part of the solution and problem already: opening the blinds exposed the inner pane to the warmer air inside and allowed the glass to warm up, closed the blinds part way and the glass was allowed to cool again.

Unlike Ken's area, in Florida we are more concerned with windows remaining in place during high wind events than we are of keeping -30° outside air outside.

Rich
Can you post some more pictures. Get one that shows the entire window from the inside.
Also take some exterior one that shows the entire elevation then one closer up.
What is the brand and model number of the windows.

Ken
Did we meet in ST Paul when I spoke at the continuing ed seminar for you guys. Tom and Reuban had me up for your fall seminar

Originally Posted by Jerry Peck

Rich,

Those metal pieces are "mulls", which is short for "mulluion" (spelling?).

They are metal (aluminum) through and through. They are the structural pieces which give structural support for the impact rating of the windows.

Not really much - if anything - can be done to those mulls, except maybe to sleeve them with PVC at the time of manufacture, but that would affect the window size and probably not really do much good regarding making a thermal break.

I think you explained part of the solution and problem already: opening the blinds exposed the inner pane to the warmer air inside and allowed the glass to warm up, closed the blinds part way and the glass was allowed to cool again.

Unlike Ken's area, in Florida we are more concerned with windows remaining in place during high wind events than we are of keeping -30° outside air outside.

Ya, I was just on the window site. It's PGT, not PGG (small print on the label). I was toying with the idea of gluing a plastic, 1/8" - 1/4" U-shaped sleeve on the outside in the same color to provide the thermal break.

Originally Posted by Rich Goeken

Ya, I was just on the window site. It's PGT, not PGG (small print on the label). I was toying with the idea of gluing a plastic, 1/8" - 1/4" U-shaped sleeve on the outside in the same color to provide the thermal break.

Rich
Gluing on a plastic strip does not provide a thermal break. This will only act as an insulator and a plastic strip is a poor insulator.
I think this a waste of time and effort
what is the model # of the window used

Originally Posted by Mark Parlee

Rich
Gluing on a plastic strip does not provide a thermal break. This will only act as an insulator and a plastic strip is a poor insulator.
I think this a waste of time and effort
what is the model # of the window used

My poor choice of words. Yes, it wuld be an insulator, but I may also point out that plastic appears to be the material of choice for thermal breaks.

My thoughts are if the material is tight enough and secure enough to the channel and sealed around the edges, it may be just enough to eliminate the cold from transferring into the home.

I need to find the model number, as usual, the builder hasn't given me that (along with a lot of othere stuff) and I need to get after him.

Pictures will take a day or so as I can't find my chip reader (just moved here last month). Still looking for it.

Rich, I was surfing around the PGT site last night after learning the windows are mulled. Some of the info I found was; PGT offers thermal break mulls as well as solid extruded, price I'm sure is the big factor. They also offer factory mulled as well as site installed mulling, probably accounts for the sticker (factory mulled).

If they are solid, which they most likely are, there are only remedies to the symptom available. 1) You can reduce the RH as Ken has suggested; 2) You can warm the window to closer to the inside temp. If your blinds are outside the window casing you could try extending them out from the wall a little to allow air to get to the glass and mulls more easily. You could point the register louvers at the windows or place a small electric heater below them. Just some ideas that might help, others are welcome to add to them.

Did you have the home built or was it a spec home? Why were metal windows chosen over vinyl?

At the risk of sounding stupid, what is meant by "the HVAC system has the dehumidify setting"?
I don't know of a t'stat that does anything other than set the fan to continuous. I can see where a t'stat could control the on time of the compressor and emulate a smaller system, but that would only be useful in the cooling season. Running the compressor while the furnace is on would produce little or no additional dehumidification and goes against the "Oh, you can't run the A/C below 60 BS". Anybody!

Originally Posted by Mark Parlee

Ken
Did we meet in ST Paul when I spoke at the continuing ed seminar for you guys. Tom and Reuban had me up for your fall seminar

Since I don't know the Tom and Reuban you're referring to I would say no.

Originally Posted by Vern Heiler

At the risk of sounding stupid, what is meant by "the HVAC system has the dehumidify setting"?
I don't know of a t'stat that does anything other than set the fan to continuous. I can see where a t'stat could control the on time of the compressor and emulate a smaller system, but that would only be useful in the cooling season. Running the compressor while the furnace is on would produce little or no additional dehumidification and goes against the "Oh, you can't run the A/C below 60 BS". Anybody!

I suspect Rich has a thermidistat, which is a thermostat and humidistat in combination. These can run the a/c system on a low enough fan speed to keep dehumidifying the air yet not cool the air.

Originally Posted by Jerry Peck

I suspect Rich has a thermidistat, which is a thermostat and humidistat in combination. These can run the a/c system on a low enough fan speed to keep dehumidifying the air yet not cool the air.

Here is what I have found;

Comments about Honeywell VisionPro IAQ Programmable Universal Thermostat with Total Home Comfort Control:
The VisionPro IAQ has so many features, I believe its better than the internet thermostats that need to micromanage it via cell phone. Automatic change over from heat to cool in the spring & fall. Automatic humidity control in the winter and will use the AC to dehumidify in the summer even if it isn't hot enough for AC. Can add additional sensor in the house, and run multiple zones in the house.

Doesn't look like it can use the A/C to dehumidify in the winter. Also only goes down to 40% RH setting. This is the only one I researched, Rich may have something different, I'd be interested to know.

Vern,

Check this out:
Thermidistat - Carrier

I'm working from my cell phone so it is a bit difficult to read every like that, but I suspect you will find what I am referring to in there.

Originally Posted by Jerry Peck

Vern,

Check this out:
Thermidistat - Carrier

I'm working from my cell phone so it is a bit difficult to read every like that, but I suspect you will find what I am referring to in there.

IDEAL HUMIDITY SYSTEM® TECHNOLOGY

​Only works in the summer cooling mode.

Originally Posted by Vern Heiler

IDEAL HUMIDITY SYSTEM® TECHNOLOGY


​Only works in the summer cooling mode.

I don't see that (back in my office now) but I do see this: Heating Humidity, so the thermidistat does adjust the humidity during heating, but ... one must also have the following to adjust the humidity during heating:
- If you have a whole house humidifier, heat recovery ventilator (HRV) or energy recovery ventilator (ERV) as a part of your system, you can select your desired heating humidity setting and change how your system controls the humidifier or fresh air ventilation.

Being in Florida, I doubt the builder installed the required components for it to work during heating.

Originally Posted by Jerry Peck

I don't see that (back in my office now) but I do see this: Heating Humidity, so the thermidistat does adjust the humidity during heating, but ... one must also have the following to adjust the humidity during heating:
- If you have a whole house humidifier, heat recovery ventilator (HRV) or energy recovery ventilator (ERV) as a part of your system, you can select your desired heating humidity setting and change how your system controls the humidifier or fresh air ventilation.

Being in Florida, I doubt the builder installed the required components for it to work during heating.

Just caught up with this discussion. Yes, I discovered when I turned on the heat that it would not dehumidify. The dehumidify changed to humidify, and to my knowledge we don't have one, or a heat exchanger. We can only take in a small amount of fresh air. Up until the freeze the unit was dehumidifying, so the house was low. Every so often you could tell that is was running for a while even though the house temp. was OK. It appears that to activate that function you need to be on cool only, not heat and cool. The settings for that, BTY, are separated by 8 to 10 degrees.

We are supposed to have the mfd. rep here, maybe I can get the to change the munions to ones with a thermal break.

Originally Posted by Paul Kondzich

47% is not high in Florida this time of year when you don't have your A/C on much. I just glanced at my indoor humidity and its 53%. This is not MN. Where your gas furnace dries the air out to the point of static and humidifiers. Kinda cool here today at 60 degrees

Furnaces dont dryout air. It is the air leaks letting the moist air out and replacing it with dry air from outside.

You said this is a new home. Is it slab on grade. A lot of moisture will be released during the first year from lumber and concrete. Depending on the air tightness of the house....assuming it is reasonably good...you need some type of mechanical ventilation. What is you mechanical ventilation? Is it running.

Typically as it gets colder the humidity level goes down. Thus pulling in dryer outside air will lower the indoor humidity level. Off course being a Midwesterner I dont deal with coastal humidity.

Does your house have an ERV? If it does then maybe the rate needs to be increased. You can run the bathroom fans continuously if you dont have an ERV.

Originally Posted by Robert Hronek

You said this is a new home. Is it slab on grade. A lot of moisture will be released during the first year from lumber and concrete. Depending on the air tightness of the house....assuming it is reasonably good...you need some type of mechanical ventilation. What is you mechanical ventilation? Is it running.

Typically as it gets colder the humidity level goes down. Thus pulling in dryer outside air will lower the indoor humidity level. Off course being a Midwesterner I dont deal with coastal humidity.

Does your house have an ERV? If it does then maybe the rate needs to be increased. You can run the bathroom fans continuously if you dont have an ERV.

I think this problem is solved due to previous suggestions/comments. Thanks.

Background: This home has been up and ready from April of 2013 to November 2013. Construction is slab, steel studs, with sheetrock construction. HVAC system allows a small amount of fresh air intake, but not EVR. Closing was November 2013 and from that point HVAC was in the dehumidify cooling mode and on constant air. Window is double pane and facing North.

Recent cold spell was cold enough to cause severe condensation on the windows. In testing and referring to comments here, I have determined there is insufficient air flow over the windows, even with ceiling fan running in the room and the HVAC system in constant air, apparently due to the blinds placement.

The solution that I have come up with it to build a 4" frame around the window. Then move the blinds out 3" and provide 2" x 18" vents top & bottom between the windows and the blinds. This should provide ventilation flow drop across the the windows. Hopefully, this will solve the problem.

Originally Posted by Rich Goeken

I think this problem is solved due to previous suggestions/comments. Thanks.

The solution that I have come up with it to build a 4" frame around the window. Then move the blinds out 3" and provide 2" x 18" vents top & bottom between the windows and the blinds. This should provide ventilation flow drop across the the windows. Hopefully, this will solve the problem.

Rich
Keep us posted as to the results of your "fix"
Take a picture of the current view of the wall and another at completion of your correction and post them if you would.

Originally Posted by Mark Parlee

Rich
Keep us posted as to the results of your "fix"
Take a picture of the current view of the wall and another at completion of your correction and post them if you would.

Can do.

Originally Posted by Rich Goeken

I think this problem is solved due to previous suggestions/comments. Thanks.

Background: This home has been up and ready from April of 2013 to November 2013. Construction is slab, steel studs, with sheetrock construction. HVAC system allows a small amount of fresh air intake, but not EVR. Closing was November 2013 and from that point HVAC was in the dehumidify cooling mode and on constant air. Window is double pane and facing North.

Recent cold spell was cold enough to cause severe condensation on the windows. In testing and referring to comments here, I have determined there is insufficient air flow over the windows, even with ceiling fan running in the room and the HVAC system in constant air, apparently due to the blinds placement.

The solution that I have come up with it to build a 4" frame around the window. Then move the blinds out 3" and provide 2" x 18" vents top & bottom between the windows and the blinds. This should provide ventilation flow drop across the the windows. Hopefully, this will solve the problem.

Curious about your construction do you have steel studs in an exterior wall? What is the construction of the home.

I think the correct solution is to find the what the real problem is. I dont think it is air flow or lack of it across the window.

Did you measure the window temps? How did you measure the RH. Did the home have a blower door test, how tight is it. How well is it insulated.

Looking at a dew point chart I see that at 70 degree air temp and 45% RH the dew point is 47. I would think that the windows would be above that temp. Now if the rh was 60% the dew point jumps to 55 degrees. I would expect the inside glass would be over 20 degrees warmer than the outside air temps. I just measured a window with 31 degree air temp and inside glass was 60 degree with the blinds closed. That is 29 degrees above the air temp.

If you read Joe L's stuff at BSC he has talked about the amount of moisture released during the first year after a home has been built.


Do you the rate at which ventilation air is being introduced in to the home? What controls the ventilation?

If the outside temp was 40 the dew point of that air was probably lower than that. If you ventilated with outside air as this air warmed the rh in the house would drop.

- - - Updated - - -

Originally Posted by Rich Goeken

I think this problem is solved due to previous suggestions/comments. Thanks.

Background: This home has been up and ready from April of 2013 to November 2013. Construction is slab, steel studs, with sheetrock construction. HVAC system allows a small amount of fresh air intake, but not EVR. Closing was November 2013 and from that point HVAC was in the dehumidify cooling mode and on constant air. Window is double pane and facing North.

Recent cold spell was cold enough to cause severe condensation on the windows. In testing and referring to comments here, I have determined there is insufficient air flow over the windows, even with ceiling fan running in the room and the HVAC system in constant air, apparently due to the blinds placement.

The solution that I have come up with it to build a 4" frame around the window. Then move the blinds out 3" and provide 2" x 18" vents top & bottom between the windows and the blinds. This should provide ventilation flow drop across the the windows. Hopefully, this will solve the problem.

Curious about your construction do you have steel studs in an exterior wall? What is the construction of the home.

I think the correct solution is to find the what the real problem is. I dont think it is air flow or lack of it across the window.

Did you measure the window temps? How did you measure the RH. Did the home have a blower door test, how tight is it. How well is it insulated.

Looking at a dew point chart I see that at 70 degree air temp and 45% RH the dew point is 47. I would think that the windows would be above that temp. Now if the rh was 60% the dew point jumps to 55 degrees. I would expect the inside glass would be over 20 degrees warmer than the outside air temps. I just measured a window with 31 degree air temp and inside glass was 60 degree with the blinds closed. That is 29 degrees above the air temp.

If you read Joe L's stuff at BSC he has talked about the amount of moisture released during the first year after a home has been built.


Do you the rate at which ventilation air is being introduced in to the home? What controls the ventilation?

If the outside temp was 40 the dew point of that air was probably lower than that. If you ventilated with outside air as this air warmed the rh in the house would drop.

Robert
How are you measuring the window temperatures?

Originally Posted by Mark Parlee

Robert
How are you measuring the window temperatures?

(Rich) I was using a Black & Decker Thermal Leak Detector TLD100 that probably has, at the temperatures I was looking at, around a ±3-4°F accuracy at 40°-60°F. So long as the error, whatever, is consistent-----it is fine for my purposes, especially since I got it on sale!

Rich
thatdevice should get you some good relative measurements for temperature. You dohave to be close as the spot size really grows as the distance away from theobject increases. Also background temps and reflectivity comer into play aswell.
Whentaking the temperatures you should be no more that a couple of inches away.

I was doing a little playing with mine this morning and comparing it to my thermalimager as well as a direct attached thermocouple. I was surprised that therewas not a bigger difference in all of the readings I took; makes me appreciategood equipment.

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