white powdery dust from air conditioner?

Question

I wonder if anyone can help me with this problem. I have this white powdery dust all over the house, assuming it is coming out of the AC ducts. I had the ducts cleaned, change my filter in the AC every month (just bought one that can be rinsed out with the gardenhose) and it's still visible all around the house......??? Anybody have a clue as to where this comes from......??? Do I need to have the ductwork replaced (the house is 10 yrs. old)...??? Any comments will be greatly appreciated.........

Answer 1

I suspect that you may be getting insulation blowing in around your vents from the attic. This is easy enough to determine . Simply gather up a plie of the dust in your fingers. If it is fibrous and spongy, it is most likely insulation. To further confirm, you might want to take a sample from your attic and compare the two. If this proves to be the case, here is the fix:

Remove the a/c grilles from the ceiling and clean them. Using latex caulk, carefully seal the opening around the metal can in the ceiling where it abuts the drywall. Work this in with your finger for a good seal. After your grilles are dry, replace them.
After you are sure the problem is resolved, have the ducts cleaned to remove the balance of loose fiberglass from the ducts.

There are two other possibilites in the event the dust proves to be granular and not fibrous. If you have had you attic dusted for carpenter ants, the Borax-based powder may have been pulled in to the ducts through leaks and disseminated throughout the home. This powder is very abrasive and tough on the lungs. The material must be removed from the areas on and around the ducts, and the ducts must be thoroughly cleaned. This expense should be born by the pest control company, as this product should never be applied near an air distribution system.

Another scenario that I have encountered is less likely, but still a possibility. If the dust is metallic, particularly aluminum dust, the evaporator coil may be deteriorating. This can be a reaction to cleaning with acid, or simply a manufacturer's defect. This will require replacement of the defective coil and a thorough duct cleaning.

I encountered an extremely unusual scenario that I will list, even though it most likely will not apply. A client had installed ozone-producing u.v. lights in his duct system. The ozone broke down the protective scrim of the fiberglass ductboard, and the air movement across the exposed fiberglass released a considerable amount of dust throughout the ducts and the home. This required replacing that section of duct and cleaning the loose fiberglass from the duct system.

I hope you can find the solution to your problem in one of these examples. Good luck and God bless you!

Answer 2

The white powdery stuff is just by products of the moisture in the air. Your a/c is shooting out cold air and it is reacting with the hot air in the house. The chemical reaction puts the white powder throughout the house. (that's why it's everywhere instead of just in certain places). You could put a dehumidifier in the house and it will reduce the white powder. Good Luck

Answer 3

White powder like chalk? If so, I'd guess drywall.

there may be a problem with something rubbing on the drywall creating chalk dust. Maybe out of ballance blower fan shaking A\C housing.

Answer 4

Yes