Low Air Pressure and Dust

Question: I have a dust problem in the master bedroom and its bathroom. I have sealed the shower vent, electrical outlets and cutouts behind the medicine cabinet and toilet paper dispenser because dust accumulated in those areas. It doesn't appear to come from carpeting or fiberglass insulation in the attic.

The dust is very fine, white and soft and looks like lint from the clothes dryer. It is hard to imagine it is traveling from the laundry/furnace room on the first floor to the bathroom on the opposite end of the second floor. (I repaired an improperly installed dryer vent many years ago.) The furnace and electronic filter are new. I have also sealed all accessible ductwork near and around the furnace.

The laundry/furnace room is the only area of the house that does not have a ceiling so that air can travel not only through the ducts but also between the joists to the space between the bathroom/bedroom and the ceiling of the garage. The bathroom and bedroom air vents are at the end the ductwork.

I have tried sealing off the bathroom vent, but that made no discernible difference. I had someone inspect the ductwork within the past year. He could not see that the ducts needed cleaning. If he cleaned them, he would have to work from the center of the house because of its length, requiring cutting into the ceiling on the first floor.

Answer: Very, very low air pressures inside a home can create a highway for dust particles to travel. I suggest you close the open ceiling of the furnace/laundry room to equalize pressures.

Also, an electronic filter is not designed to remove that much dust. Try using a disposable media filter that is 30 percent to 50 percent efficient at removing dust and other particles. Replace the electronic filters with disposable filters, and change the filters every month or two until the dust problems are solved. Then replace the electronic filters or continue to use the media filter.

Too much dust can damage the electronics. Thick, efficient media filters are available for under $30 each through heating contractors or online.

Dwight Barnett is a certified master inspector with the American Society of Home Inspectors.