My house is just over 1 year old and I have vinyl clad windows. With the onset of colder temperatures, I noticed a lot of condensation on the bottom portion of my windows. Now there is mould on the inside of the windows at the bottom, particularly in the corners. I have a guage in the bedroom that shows humidity readings anywhere from 40% to 80%. What's causing this excess humidity in my new house and what should I do to get rid of it? I've cleaned the mould with an antibacterial cleaner but it'll likely be back unless I do something to fix the problem.
Answer:
During the first and second winters after a house is built, there will be all kinds of atmospheric humidity in there because all the water that went into building it has to somewhere and it is attracted to the inside. 80% atmospheric humidity is just too high whereas 40% is not. Try this: Cold air holds more moisture than warm air and is, therefore, heavier. As air cools, it falls and keeps falling until it reaches the lowest level in the house. It cannot fall beyond the basement floor and that is where it has to be collected and pumped outside before that moisture gets a chance to condense in order to get rid of the moldy, musty odour and/or avoid it in the first place. A booster fan (250 CFM +) is available as a ‘pop in’ unit to fit 4”, 5” or 6” round heating duct. This can be installed in a totally separate duct line that is at least six feet from the nearest heat source. A timer on it will ensure that it operates only during the night (9pm to 9am) so cold, moist air it pumps out is not replaced by air that brings in even more humidity from outside. All joints and seams in the duct are taped and sealed for maximum efficiency and rather than a heating-type grill it should be a return air-type grill. To avoid having to core another hole in the foundation wall, this system can be vented, via a “TY” through the clothes dryer vent. Because none of the doors in the house go all the way to the floor, cold, moist air should find its way to that grill.
