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Condensation on inside of windows
Posted: Fri Oct 09, 2009 10:15 am
I searched for this topic on here but didn't find anything. My apologies if it has been addressed before.
Does anybody have a problem with condensation forming on their inside windows during winter? I've done some searching online but found conflicting information about why it happens and how to combat it.
Live in a Cliff May house with a lot of windows. It's in the 50s outside and 70 inside (not using heater yet). Don't have a washer/dryer yet so that isn't adding to it. I cracked a window but that hasn't seem to do much plus I can't leave it cracked overnight. Same goes for keeping the shades up.
Posted: Fri Oct 09, 2009 10:35 am
Just stop breathing, that will make it go away! There's not a lot you can do, but if you keep them really clean, dirt free, and have something to wick up the moisture, small towel or something, that may help. I'm guessing you have aluminum windows? I'm also guessing that you get it worst in the bedroom? Everyone should sleep with the windows open, helps build a manly constitution! (that's a joke) Unless you have pets you'd rather not have sleeping with you, you might want to keep all the doors open, just the ones inside, this will help too; you won't be confining the moisture in your breath to one room.
Posted: Fri Oct 09, 2009 10:44 am
haha--yeah, and by stopping breathing, I wouldn't worry about it either!
The windows are wood. And actually, it's the same through out the house. We keep the inside doors open all the time. (Well, except for bathroom trips
Posted: Fri Oct 09, 2009 11:26 am
Um, they have stuff you can buy in small tubs to soak up the moisture, for RV's an' stuff like cabinets; you may want to have them in each room, like say under the bed, near/under the water tank of your toilet, etc. they do work.
Are you sure you don't want to stop breathing: dang, you're pretty selfish, think of all the other people who NEED that air?
A fan to circulate the air might help too, you know like an Oscar-lating:
I mean and oscillating fan:
Yeah, I know I'm a smarty-pants!
Posted: Fri Oct 09, 2009 11:47 am
Humidity is apparently a problem in parts of Texas. That is the reason many folks there run their A/C to de-humidify. It's also the reason it is important not to oversize an A/C system. Oversize systems cycle more instead of running continuously. For questions related to A/C see this forum:
You can also buy and run a dehumidifier.
Posted: Fri Oct 09, 2009 3:15 pm
this happens to single pane windows when it's warmer inside than out with a dash of humidity. no worries.
happen with me when I take a shower.
just make sure whatever wood that is exposed to the moisture is painted.
Posted: Fri Oct 09, 2009 3:21 pm
Posted: Sat Oct 10, 2009 5:39 pm
A someone who has a fair amount of experience with this issue, I can tell you that running an exhaust fan vented to the outside while showering and cooking will do a lot to help. We installed timers on our exhaust fans to let them run for a while after we leave the bathroom.
Beyond this, the best defense against condensation on windows is moving air. This is one reason why many houses have the supply air registers in the floor below the windows.
For us the problem seems to be the worst in the shoulder seasons when we have no forced air or heat running. This reinforces the moving air theory.
If you have a forced air system you might try running the system in fan mode without the heat or air being on.
Posted: Sun Oct 11, 2009 4:35 am
All my windows are double paned, low-E and they all "sweat" - especially the clerestories and sliding glass doors. I don't think the glass itself is so much the culprit as the seal around the windows. I recently replaced the front entry door and found almost no insulation between the door and window above - my plan is to put something much more efficient in the space. I do have exhaust fans on timers, etc as already suggested - they don't really help. But I'm in Atlanta where the humidity is often 70-80% - on mornings when it's been cold and wet I've gotten used to placing towels in the sills and use a long-handled squeegie to force as much water into the towels as possible before removing. I've looked into a whole-house dehumidifier but right now there are more pressing issues so it'll have to wait.
Posted: Sun Oct 11, 2009 8:23 am
We have double pane insulated, low-e windows as well.
I would guess Atlanta has a much longer shoulder season and higher humidity that makes sweating a bigger problem.
Have you tried placing a fan to get more air moving around the windows?
Are your bathroom and bedroom areas worse than other parts of the house? Are you sure your exhaust fans vent to the outside and not just to an attic or other dead space?
I actually had two exhaust fans that vented into my attic and one that went no where when I moved into my house. We have fixed that problem.
Posted: Sun Oct 11, 2009 10:00 am
MRU--great idea for the fan mode. I never even thought of that. I always wondered why people would use fan mode. And the house has floor registers so even better.
Posted: Sun Oct 11, 2009 7:29 pm
Posted: Mon Oct 12, 2009 8:12 am
We had this issue in our bedrooms and were getting mildew on the window panes. Started running the bathroom exhaust fans at night and it took care of the problem.
Posted: Mon Oct 12, 2009 8:22 pm
Condensation on the inside in winter:
It's a common thing to experience this if you have and gas-fired appliances that aren't vented properly such as furnace, water heater or dryer.
Our boiler did this just last year after our closing and I discovered the electric pusher fan in the boiler's exhaust flue was locked up. Once I rebuilt the motor and the exhaust flowed again, the condensation was gone in a day.
Posted: Tue Oct 13, 2009 7:13 am
Posted: Fri Dec 11, 2009 7:02 am
On a related note:
Most of the Cliff May home foundations here in Dallas are concrete slabs built on grade. From the ones I have seen, the HVAC ducts are located underground. Here is Texas, I would assume that the climate would have little affect on transfer loss in underground duct, but I am curious of what design may have been used. Assuming that PVS (Polyvinyl Steel) was not used, does any one have any details of this condition for the Cliff May homes?
Posted: Fri Dec 11, 2009 8:04 am
Condensation results when the tempurature of the surface of glass is lower than the dew point. The dew point is dependent on humidity. The higher the humidity, the higher the dew point. Single pane glazing will provide a surface temperature very close to the exterior temperature. In your bedroom, the humidity is high because you are breathing. Of course, the kitchen and bathrooms have increased humidity for other reasons.
I have replaced the glass in my May home (a stone's throw from Joe Bathlow's) with double glazed assemblies. This has greatly reduced, but not eliminated, condensation on the inside of the glass. Wood sashes are realtively good conductors of heat and cold, so they transfer the exterior cold to the interior pane of glass.
If your home is in Texas, I can imagine that double glazed assemblies would be of benefit in the summer. As a bonus, in your climate, your winter condensation problem would likely go away altogether. It requires some work but double glazed assemblies can be installed in a way that preserves the appearance and integrity of the original sashes.
Posted: Fri Dec 11, 2009 9:39 am
Posted: Fri Dec 11, 2009 10:40 am
Don't forget that many MCM homes have radiant floor heat, so they lack the air circulation you'd have with forced air HVAC. Without the air circulating as you'd have with forced air, the moist air in parts of a house does not get to move around and neither does the moisture. Because of this, that moisture will condense. Move that air around and you'll find that helps a lot.
Also note that with a heated slab, you may have a very slight plumbing leakage that isn't large enough to show up as a wet spot on the slab yet the small amount of water leaking from the pipe may constantly release moisture through the porous concrete into your house without being seen.
Any good HVAC contractor with a thermal imaging camera may be able to spot this if the floor is all exposed. There are also instruments used by concrete workers that can measure moisture content in cured concrete. If you take reading all over the slab, you may find parts that show higher moisture readings than others to give you a clue.
I was getting condensation in my place again this past spring and the culprit was moisture coming though the inside of the concrete block wall in the basement caused by faulty downspout underground terracotta pipe leaking against the outside of the wall. The moisture was almost undectable on the inside of the wall, but it made it moist all through the house. Once the problem was corrected, the concrete block "dried" and the condensation went away.
I suffer from the same lack of circulation since I have hydronic baseboards and heated floors. I am going to install a circulator throughout the house next year with 4" ducts in the ceilings to assist in moving the air around.
Posted: Sat Dec 12, 2009 5:02 pm
Window condensation is a dance between window pane temperature, moisture content of the air inside the house, and air circulation.
The last thing - air circulation, causes air coming into contact with cold glass to be replaced by warmer air faster. It also quickens heat transfer through the glass to the cold outdoors.
The middle thing - indoor air moisture content, can be controlled by ventilation and degree of supplemental humidification. Natural ventilation of most average residential frame construction increases as the difference between indoor and outdoor air temperatures increases. This tends to dry out the house, in addition to any duct leakage in ducts run through a ventilated attic. If a house is running fairly high humidity levels on cold days, and there is moisture condensing on the windows, the house may of more airtight construction and/or be slightly under ventilated. Source control ventilation of high moisture generation areas, such as bath and kitchen fans, is advisable for more airtight construction.
The first thing - window pane temperature, is largely reliant on the design and construction of the window unit. Single pane metal frame windows are the worst for almost any climate. For DFW they are wonderful conductors of heat both summer and winter, exactly the opposite of what a window needs to be. Short of replacing them with better windows, the only ways to keep them from sweating is to either maintain the indoor air dew point temperature below the coldest section of window (i.e. let the house get drier) or increase air replacement at the window (at a penalty of accelerated energy loss through the glass and possible comfort issues).
The mid-century modern houses I've dealt with mostly leaked like sieves and would only see condensation on very cold mornings with an elevated amount of moisture generation having occurred the previous evening. My own MCM house was like this until I undertook air tightening procedures. It retains moisture and heat considerably better than when I bought it; my double pane sliding glass doors I installed earlier this year NEVER sweat, even on the coldest mornings we've had so far. Indoor relative humidity levels now are not difficult to hold in the high 30's-low 40's at normal room temps, whereas before it was impossible to get it out of the low 20's with two humidifiers running. And of course I never saw condensation then.
Posted: Tue Apr 20, 2010 1:24 pm
Posted: Tue Apr 20, 2010 1:26 pm
Posted: Tue Apr 12, 2011 8:27 am
Thanks everyone for your help!
Posted: Fri Apr 15, 2011 10:31 am
We get condensation and ICE in the winter on the inside of one of our sliding doors. We have a whole house humidifier/dehumidifier. It helps a TON... (or we would get it on our windows) but in the times when we are below 15 degrees we will get the condensation and the ICE. I have yet to find a way to get rid of it totally. removing the carpeting helped... we also run a space heater at these times, it seems to help a great deal too.
We have some water damage to some window trims. I am assuming the owners before us forgot to turn the humidifier to the WINTER setting before they took off to their winter home in Florida. The condensation must have sat there all the winter months
luckily it seems it was just one season this happened.... it's not to great of damage.
Posted: Fri Apr 15, 2011 12:19 pm
van, we need to see some pics of your new landscaping
Posted: Fri Apr 15, 2011 1:07 pm
Posted: Sat Apr 16, 2011 7:37 pm
Posted: Sat Apr 16, 2011 7:55 pm
Posted: Sat Apr 16, 2011 8:39 pm
Posted: Sun Apr 17, 2011 7:50 am
We ended up springing for 3 Sonos speakers (wireless system) for the music. One really nice thing about having at home--stuff you buy for the wedding you can continue to use!
I made a separate post about wedding stuff here:
I've put up pictures of the invitations, etc I made.