Replies

1. 
   Geoff_B | Dec 11, 2001 02:10am | #1

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   Your problem may be because its a new house. Remember all the water in paint,concrete,drywall compound,etc.. Well some of it found its way into the framing and plywood which now will slowly dry out. It should correct itself, give the builder notice he'll probably wait and it should self correct.

   Good Luck

1. 
   Bob_Walker | Dec 11, 2001 02:22am | #2

   *I agree with Geoff, it's probably just the construction related moisture.Excessive humidity can be the result of improper venting of the furnace/boiler which can be dangerous - possible carbon monoxide poisoning; so be sure that it's i not related to the heating cycle (there can be a lag time.)

1. 
   RayT | Dec 11, 2001 03:45am | #3

   *Sean;Don't panic yet.....there are lots of possible reasons for sweating windows, and most of them have nothing to do with the builder screwing up. One of the pages in the new homeowners book that I give to everyone for whom I build a house includes the following information:Building technology has come a long way over the last 30 to 40 years. Houses used to have trouble keeping their occupants comfortable. The windows were cold, there were many air leaks (large & small) that let outside air in and inside air out. There wasn’t much insulation in the walls or ceilings, and the insulation that was there had gaps and voids in and around it that greatly decreased it’s effectiveness. It took lots of energy to keep these houses warm or cool. The term “vapor barrier” was not used much and was understood even less. Excess humidity was seldom a problem then. In fact, the opposite was more likely the problem. Very dry air caused wood to shrink, noses to be dry, and static electricity in the air. I remember when I was young, we kids enjoyed shuffling our feet on the carpet and zapping each other with a painful shock of static electricity. It was quite annoying when it was unexpected !! The constant exchange of inside and outside air also caused another problem. It moved the humidity (or moisture) inside the house through the walls to the outside because inside air is almost always more humid than outside air. As this moist air moved through the walls, it would condense when it came in contact with a colder surface (much the same way a cold can of pop or a cold glass of tea will sweat on a hot day). It will always “sweat” on the warmest side of the cold surface, which usually meant the inside of the outside walls. Often we run into rotted framing lumber in these older houses caused by exactly this. Over the last few decades we have been using products such as vapor barriers that effectively stop the moisture and does not let it through, thereby reducing the likelihood of condensation in the wall cavities. That does seem to have helped the rotted framing problem. However, now homes are built so tightly that we have a relatively new problem to deal with - - - excess humidity inside the house. This moisture cannot escape through the vapor barrier and thus accumulates on the coolest surfaces inside the house. Its presence is seen through the growth of mold and mildew (particularly prevalent in bathrooms) as well as foggy and/or sweating windows. If this excess moisture is not dealt with, it will cause poor indoor air quality (translated respiratory & health problems) as well as streaks, stains, damp spots, and in extreme cases, decomposing sheetrock.So……..what can we do?Normal daily activities release large volumes of water into the air inside our homes. The average family will release about 7 gallons of water vapor into the air every day without even trying. Bathing (showers and baths) is probably the major cause of indoor moisture. If you are experiencing humidity problems you could try taking shorter and/or cooler showers that use less hot water. And open a window or use your bathroom exhaust fan !! Turn the fan on during your shower or bath, and leave it on for at least 30 minutes afterward. If this becomes troublesome, install a simple timer. This uses very little electricity and will make a huge difference. Other things that contribute to indoor humidity can include cooking, washing clothes, hanging clothes out to dry indoors, automatic dishwashers, house plants, aquariums, human and animal breathing, perspiration, etc. Common sense solutions such as staggering bath times, putting lids on boiling water while cooking, using your exhaust fans, and just opening up some windows when conditions permit will go a long way toward reducing interior humidity. If your lifestyle will not allow the causes to be eliminated, you can have whole house ventilation systems installed that will exchange all the humid inside air with fresher (hopefully drier) outside air several times a day. This could be a good investment. Window condensationOften people think their windows are defective because water condenses on them. The truth is that their windows are probably performing perfectly! Older windows leaked vast amounts of cold air into the house. This dry, cold air mixed with the warm, humid indoor air and lowered the overall humidity in the house. Newer insulated windows stop that dry outside air infiltration resulting in a higher indoor humidity! This higher humidity tends to condense on the cooler glass surface. The windows fog up first because their surface is colder than the surrounding surfaces. Most windows, even the newer Low E, argon filled ones, have an R value of less than 4.5 compared to R19 found in most of today’s walls and R38 or higher in the attic. The windows are obviously going to be the coldest surfaces in the house, so you’ll notice condensation there first. ConclusionHumidity is not all bad. Some humidity in the air makes us much more comfortable. But in today’s tight houses, it is certainly something that you want to keep under control. Hopefully these common sense suggestions will help you eliminate excess moisture and keep your indoor humidity problems to a minimum.

1. 
   K_Johnston | Dec 11, 2001 06:33am | #4

   *Get a hygrometer to measure your inside humidity. It should be between 40 - 60%. Bieung a new house it is probably high. Always use your bath fans if you have them or turn your heat recovery ventilator up a notch if you have one. If you don't have either of these leave a window open a crack to allow dry outside air in and let moisture laden air out.

1. 
   iron_helix | Dec 15, 2001 02:49pm | #5

   *Point of Concern:Check it out for where you live...............but in mid-America where winter temps are at or below freezing an interior humidity of 40-60 percent would cause your windows to "rain" with condensation!I think you will find that to correct the "sweating " windows you will have to see the winter interior humidity drop below 30.Consult "dew point" tables and measure the temp of your interior glass surface with an instant read cooking thermometer to see what is really happening.It is important to correct the sweating, as it will eventually cause the wooden sash rails and sills to rot...............Iron Helix

2. 
   Randy_Rogers | Dec 22, 2001 08:22pm | #6

   *Many very good thoughts but I would also like to add: Most folks seem to think that 50% humidity is necessary in a home but in my experience that is much too high and will lead to odors, mold growth, and certainly interior window condensation. 30% - 40% is recommended humidity. If problem is building materials in new home (concrete floor and walls in basement will bleed many gallons of vapor) a dehumidifier will solve problem. Homes that are very tight will benefit from an air exchanger. Don't negate carbon monoxide as is very real problem in newer homes that make use of exhaust fans without proper infiltration of makeup air. Moisture a major ingredient of natural gas combustion.

3. 
   Phil_ | Dec 26, 2001 03:11am | #7

   *We have a very tight house and I agree with your with your booklet (a good idea) but one area not mentioned is the bedroom. This room is not usually equipped with a vent fan and a night worth of human breath puts is a lot of moisture. I strongly recommend and open window even in the dead of winter. This is a new concept for some people. Phil

4. 
   piffin_ | Dec 26, 2001 03:37am | #8

   *I've said it before, Houses are happy and healthy at about 20% but people are happy at 40% Pick your median

5. 
   Dave_Riggs | Dec 26, 2001 04:15pm | #9

   *My humble opinion: Most homes are "underfanned". Tight designs require a lot more cfm to move air. 150 to 200 cfm is not that much if there is no air to get in to replace it. Also, does your home have an air exchange kit? Most tight homes do.

2. 
   sean_compton | Dec 26, 2001 04:15pm | #10

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   I am having trouble with all of the windows in my new house sweating. It occurs over night, southern windows "burn off" in the morning, all others remain wet. being that it is a new house what could the causes. this is my first house so I am clueless. If it is improper installation it should be covered by my new home warranty, but I thought I would ask if there is anything I should try first. Any suggestions? It should be known that I live in the northeast and this problem has only started to occur since the tempeture started to drop. Also it happens whether the heat is on or not. Any suggestions would be helpful.