Dusty smell in house when AC is OFF on a hot day.


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Old 08-15-17, 05:36 AM
J
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Unhappy Dusty smell in house when AC is OFF on a hot day.

Our whole house has a strong dust smell when the ac system is turned OFF. More upstairs than down. When the house is cooled below 74 degrees, it is less noticeable, but still present, mostly during deeper breaths it gives a slight headache feeling. If we leave for a trip and leave the AC off, when we get back home the upstairs smell is thick. Could this be from the carpet, drywall, old wood, attic insulation, wall insulation, or attic air leaking into the house? Our attic has the old pink insulation, and has roof top vents and soffit vents. The attic fan appears to be turned off. Built is 1994.
 
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Old 08-15-17, 05:43 AM
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Carpet was my first thought. I shampooed carpets on & off, for 23 years. People don't realize how dirty they get. It may not fix the problem but it's needed. What about the AC filters? When were they replaced? Do you have any pets?
 
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Old 08-15-17, 08:21 AM
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My first two guesses would be the carpet and the duct.

Carpet should be steam cleaned at least twice a year to remove dust and debris. If older than 10-12 years its time to replace.

Duct could not be sealed and when the system is off the dirty/dusty air is drawn into the living space. Duct should be sealed. This would be my first correction.
 
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Old 08-15-17, 09:45 PM
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The carpet smells fine up close, and the smell is downstairs as well as upstairs with no carpet downstairs. No pets in the house. AC filters changed every 1-3 months. The attic has a similar smell when hot.
 
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Old 08-16-17, 04:28 AM
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What did you mean when you said that the attic fan appears to be turned off? Is there no juice going to the switch? Is a breaker in the off position? Is it what's called a "whole house fan"? Do you mind telling us your location?
 
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Old 08-28-17, 11:22 AM
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Houston. The attic fan has never turned on. Even when I adjust the knob. I ran the ac fan without ac and it smells bad. Not musty, or damp but dusty. I'll probably hire duct cleaners soon. If that doesn't work I'll have to replace the unit and duct. The house was built in 1994.
 
 

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