My master bedroom is constantly dusty. I would dust today and three days later most of the room will be cover with a layer of dust again. This is the only room in the house that is like this. Do I have a leaking duct? If so, is there a easy way to find the leak and solve the problem? Or should I just call a tech for a checkup? Thanks.

Put a piece of an AC filter, or anything else that is permeable (but won't block the airflow) over the vent, with tape or something, and see what it looks like after a few days.

AC units do not make more dust, they only blow around the dust that accumulates on the register vent and in the ducts. Realize the fact that a human sheds almost a million skin cells a day, which is why houses are the dustiest places around.

Agree with Super... The duct work can get filled with dust, dirt and debris. Likely you have buildup in your ducts that gets redistributed every time the unit comes on. You might consider have the ducts professionally cleaned - but do your homework and find a reputable service to do it - there are tons of rip-off artists that offer to clean ducts but only clean out your wallet. You might also consider special electrostatic filters - though many techs would disagree and think they add unnecessary strain on your unit. Portable HEPA air filter units may be helpful in rooms where you have the biggest problems...

JACPOT, Have you found the source of your dust and a solution to the problem?

I have exactly the same problem with dust in my master bedroom. This is very fine dust. After 2-3 days, I can write my name on the chest of drawers. I've had my ducts professionally resealed in the attic by a certified hvac technician and then had the ducts professionally vacuum cleaned inside and the grills cleaned or replaced. I still have the same problem on this, the SMALLER end of my house which also includes my bathroom and small office. The bathroom and the office which both adjoin the master bedroom are similarly dusty. The rest of my house, the LARGER part, is zoned to a different heater/air conditioner, and is not dusty like this. I have an electrostatic filter system on the heater/ac unit supplying the LARGER end of my house, but even before it was installed, I did not have a dust problem there. My SMALLER end has filters just inside the 3 return air grills, so that the return air is filtered as it enters the ducts leading to the heater/ac unit. There are no other filters on the system. I've used both MERV 8 and MERV 11 filters inside these return air grills. I also have 2 of the large Ionic Breeze GP Air Filter systems in this area. It doesn't seem to matter if I keep them turned on or off.

I've had the heater/ac units turned off for the past several days because of moderate temperatures. The dust problem is just as bad.
There are 5 outside windows in the smaller area of my house, but they also have good quality storm windows covering them. There is a central vacuum receptacle in the master bedroom but it appears to seal well. I never use it. In an adjacent room, there is a utility area containing my washer and dryer and covered by folding doors. The dryer is vented to the outside and I try to keep the area clean, but this and the vacuum receptacle are possible dust sources.

I added the office area to the end of my house 25 years ago and had the heating/ac system redesigned into two zones, adding a unit for the smaller end of my house. This area has always had a dust problem since the room was added. Does anyone have any ideas about how this addition could have caused a perpetual dust problem? There is ONE double wide return air vent in the master bedroom that is still connected to the heater/ac unit on the larger end of the house so that when that unit is ON, air flows past an outside door [which also has a storm door] and past the utility area folding door and into the master bedroom. SEE Item 3 below.

This is very frustrating. Dusting is a continuous nightmare. My eyes burn and water all of the time and my sinuses stop up regularly. These symptoms improve a lot when I am away from home for a few days.

Here are a couple of things I've considered:

1. Would it offer any insights if I took some MERV 8 filters and cut them to size and placed them inside my duct outlets and then replace the grills. Would this restrict the airflow to the point of harming the heater/ac units?

2. What if I used masking tape and sealed the vacuum receptacle and the folding door covering my utility room.

3. What if I sealed the return air vent that leads to the other heater/ac unit on the LARGER end of my house? Would this damage the unit? There are several other return air ducts for that unit in other rooms, one almost the same distance from the nearest conditioned space as the one in question.

Please offer your comments on this situation and on 3 items above.

danw, I have the same problem. I cannot find an answer, but I am going to try my own solution.
I think the dust is coming from the attic, through the small seams in the vent (the square part you see when you remove the ceiling grill). I am going to buy some metallic ac tape and seal the seams. I figure the problem has gone on so long the dust is throughout the system, so it may take a while for the dust to stop blowing out. My plan is to seal the seams in the insulation and around the opening in all the vents, install some temporary air filters in a few vents at a time and also double filter the intake. Of course the intake is filtered, and I change the filter once a month, but I intend to add some temporary open-weave fabric filtration to the space around my ac closet to further filter the air going in.
I know this will put a strain on my ac, but the secondary filters are only temporary, and I intend to change them every two weeks and monitor the results. I don't know if this will work, but it is the only thing I haven't tried. Every window and door is sealed, all outlets and switches and lighting are sealed. I have five vacuum cleaners and a roomba and a scooba, I don't dust, but wipe everything regularly with a damp cloth, and have dusted the walls and ceilings numerous times. I am also in the beginning stages of smoothing out all my textured walls (another story, lots of work, using a vacuum sander) because the textured plaster walls collect dust and I suspect contribute dust. I will seal them Gardz when I finish, before I paint them with primer and paint.
Sound desperate to stop the dust? Yep. Oh yea, I also have a portable $800.00 IQAir hepa air filtration system and two Ionic Breeze, which I have used for two years. The Ionic Breeze systems are on all the time, and I use the IQAir in each room as I dust, but it doesn't seem to do much. The dust is back in less than a week.
Oh yeah, I have two dogs, but I live alone, so the dust in my house is certainly way out of proportion the occupants. I live in Florida, very humid. I am sure the dust would be worse in a dryer climate.
If you have found a solution, I would love to hear it.

This post is over 3 years old. LOL

What everyone is experiencing is the build up of mold spores and dust mite debree. The bedroom is normally the most humid area in the home, especially if you sleep with the door closed. Each exhaled breath of air contains water vapor that increases the relative humidity (RH) throughout the night. Microscopic mold growth and dust mite activity both increase with humidity. Get yourself a hygrometer from Target or Wal-Mart and strive to keep the RH below 50% if possible, but never above 60% for any extended time. A dehumidifier may be necessary. Make sure all bathrooms, laundry room, and kitchen are properly ventilated during use.

I'm glad to know that I am not the only one going crazy over extreme dust! -- I too have central heating and air conditioning. I have asked myself repeatedly -- Is this normal!

Now that I know others experience the same thing, I'll just have to dust more I guess... at least I know I'm not going crazy!