AC duct odor

[2A supporter]

We have a musty, dank, heavy odor coming from all AC vents. The patio villa is less than 4 years old and is kept immaculate. We have UV lights above and below the air handler and an electrostatic permanent filter that is cleaned monthly. The AC works perfectly and everything visible is clean, but the odor is bad and actually burns the throat and eyes. Who do you recommend for checking the ductwork? We need a pro , not some rookie kid to diagnose the problem. Thanks in advance.

[Keefelane66]

“ For lamps that are solely used to keep bacterial and mold growth from HVAC coils and blowers, you can use these lamps for up to 18,000 hours or two years.”

[tophcfa]

Try taking out your filter, cranking up the A/C, and spraying a can of Lysol into the filter intake. When done, put in a new filter.

[Altavia]

Moisture is standing somewhere.

It's the HVAC near the laundry?

If so I'd have someone open up the drywall and look for a hairline crack in a waterline.

[villagetinker]

Do you use the dehumidify setting on your thermostat? I would check the humidity level in your house. Also, the HVAC unit in the garage should have a flow switch that monitors water accumulation in the HVAC air handler, if this gets high, it shuts off the AC, if it is working correctly.

[Topspinmo]

We have a musty, dank, heavy odor coming from all AC vents. The patio villa is less than 4 years old and is kept immaculate. We have UV lights above and below the air handler and an electrostatic permanent filter that is cleaned monthly. The AC works perfectly and everything visible is clean, but the odor is bad and actually burns the throat and eyes. Who do you recommend for checking the ductwork? We need a pro , not some rookie kid to diagnose the problem. Thanks in advance.



I would look in bottom of A coil see if more than usual standing water. Water has to drain out of A-coil down and outside by the outside unit. Do you see water dripping out the drain pipe by outside unit? Maybe the drain path plugged/blocked?

Should be tag saying who installed it? I would probably call Mums few A/C companies I trust around here. MUMs has always been straight with me.

IMO unless you have humidifier in duct works I doubt it ducts but inside the air handler unit some where which IMO points to A coil which has to drain condensation outside through drain pipes?

[Topspinmo]

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[rjm1cc]

You might have a dead animal in the duck works. Someone should look at the ducks in the attic to see if their is any damage. A company that can inspect all the ducks with a video camera might be needed.

[2A supporter]

Tried today: Removed cover plate for air handler, sprayed coils( Looked clean to start with) Collection tray was clean, Poured some water in the collection tray and it ran free and clear to outside drain, also poured a few quarts of hot water and vinegar down the drain tee and it ran strongly to the outside. Removed permanent electrostatic air filter which was clean. Felt down inside the air return box, it was dry, no leaks. Both UV lights working. Sprayed the air filter and return air box and all reachable surfaces with some odor killer suggested by Lowes plumbing associate. I climbed up a step ladder and peered back through the attic (80 year old man here) Ductwork looked ok but can't get up to see the back of the house. I guess the suggestion of a visual duct inspection is necessary. Any suggestions on a company to use?

[retiredguy123]

Tried today: Removed cover plate for air handler, sprayed coils( Looked clean to start with) Collection tray was clean, Poured some water in the collection tray and it ran free and clear to outside drain, also poured a few quarts of hot water and vinegar down the drain tee and it ran strongly to the outside. Removed permanent electrostatic air filter which was clean. Felt down inside the air return box, it was dry, no leaks. Both UV lights working. Sprayed the air filter and return air box and all reachable surfaces with some odor killer suggested by Lowes plumbing associate. I climbed up a step ladder and peered back through the attic (80 year old man here) Ductwork looked ok but can't get up to see the back of the house. I guess the suggestion of a visual duct inspection is necessary. Any suggestions on a company to use?
You buy your own camera for less than $30 on Amazon.

Amazon.com (https://www.amazon.com/Lighted-Borescope-Camera-Semi-Rigid-Adjustable/dp/B0BR7MKHF9/ref=sr_1_3?dib=eyJ2IjoiMSJ9.Zb-IsFOuVjHbgPrsIRc-7jrx1d3K1euin8_64YcxT-LKevIMrVsLV_yqEiT_3lbVs2Bra-3GXNV-aUli31IrbC35807FcyjrTK0G6VB1P80gp-lG3h_J_6lUItrB0KrTucJjNOA7VdSJ4-011zA33OY_SJsn6h6qrJ8O2TNgq4vyDf1PxHr1Kzu6RdTjWx89 UFK_Igrg2-hiG3tx40a4LSv9M2S5cGmw4duMuXfkY38.zMBDuh6OKMqw3WRX IbBKVPGPTAr6isWqqYj56fgmxH4&dib_tag=se&keywords=Duct%2BInspection%2BCamera&qid=1713720128&sr=8-3&th=1)

[CarlR33]

Tried today: Removed cover plate for air handler, sprayed coils( Looked clean to start with) Collection tray was clean, Poured some water in the collection tray and it ran free and clear to outside drain, also poured a few quarts of hot water and vinegar down the drain tee and it ran strongly to the outside. Removed permanent electrostatic air filter which was clean. Felt down inside the air return box, it was dry, no leaks. Both UV lights working. Sprayed the air filter and return air box and all reachable surfaces with some odor killer suggested by Lowes plumbing associate. I climbed up a step ladder and peered back through the attic (80 year old man here) Ductwork looked ok but can't get up to see the back of the house. I guess the suggestion of a visual duct inspection is necessary. Any suggestions on a company to use?I would say you have done what you can to save money by checking the obvious so I would now call an HVAC person and ask their opinion. If you just do duct cleaning and that is not it then you just threw your money away. A reputable HVAC company should be able to diagnose it.

[retiredguy123]

I would say you have done what you can to save money by checking the obvious so I would now call an HVAC person and ask their opinion. If you just do duct cleaning and that is not it then you just threw your money away. A reputable HVAC company should be able to diagnose it.
If you have flexible ducts, I would not do duct cleaning. It can puncture the ducts, and it probably won't solve an odor problem.

[JMintzer]

Tried today: Removed cover plate for air handler, sprayed coils( Looked clean to start with) Collection tray was clean, Poured some water in the collection tray and it ran free and clear to outside drain, also poured a few quarts of hot water and vinegar down the drain tee and it ran strongly to the outside. Removed permanent electrostatic air filter which was clean. Felt down inside the air return box, it was dry, no leaks. Both UV lights working. Sprayed the air filter and return air box and all reachable surfaces with some odor killer suggested by Lowes plumbing associate. I climbed up a step ladder and peered back through the attic (80 year old man here) Ductwork looked ok but can't get up to see the back of the house. I guess the suggestion of a visual duct inspection is necessary. Any suggestions on a company to use?

ServePro...

The previous owners of our house had two large dogs, which unfortunately, I have allergies to. We had them come to our home and do a deep clean of the house (even the refrigerator vent was covered with dog hair). They also cleaned the ductwork. No punctures, and they sprayed the vents with the best smelling disinfectant I ever smelled! Zero allergy problems afterwards and I couldn't be happier with their work.

[Shipping up to Boston]

I agree with an earlier post...it’s possible you have a carcass decomposing in the ducts. Musty is more typical of what’s been stated already but the ‘burning of throat and eyes’ sounds more that than anything mechanical. Maybe you can post a follow up. Good luck

[RICH1]

YOU HAVE MOLD IN YOUR AIR HANDLER . The Evaporator and Tray is the breeding area.... Call a Reputable AC outfit to Clean it for you! They see it all the time in FLA. (Vacant sitting houses) former HVAC Tech

[Topspinmo]

We have a musty, dank, heavy odor coming from all AC vents. The patio villa is less than 4 years old and is kept immaculate. We have UV lights above and below the air handler and an electrostatic permanent filter that is cleaned monthly. The AC works perfectly and everything visible is clean, but the odor is bad and actually burns the throat and eyes. Who do you recommend for checking the ductwork? We need a pro , not some rookie kid to diagnose the problem. Thanks in advance.


Have found out anything yet? If so, or when please post the findings and results. DON’T leave us Hanging!:shrug:

[Smalley]

Have found out anything yet? If so, or when please post the findings and results. DON’T leave us Hanging!:shrug:

We have been so pleased with M&S air conditioning company. They have done inspections and large projects for us and everything has gone well. Good luck!

[2A supporter]

YOU HAVE MOLD IN YOUR AIR HANDLER . The Evaporator and Tray is the breeding area.... Call a Reputable AC outfit to Clean it for you! They see it all the time in FLA. (Vacant sitting houses) former HVAC Tech

Sorry for the delay in getting back to everyone who was kind enough to give suggestions. I decided to use ServePro to inspect and service the ductwork. They create negative air pressure in the ducts and suck everything out to a big unit in the garage. Supposedly, ducts were then cleaned by a flexible air whip type device which doesn't harm the ductwork. I could not watch the process in the attic, old man here! I'm assuming everything was done as stated! The Tech said nothing found in the ducts but some original construction very light dust, etc. No moisture, dead animals, etc. Then everything was sprayed with a great smelling product through the air handler. All was fine for about 48 hours, then the odors returned! SOB!! OK, I opened the air handler and reinspected the coils, fins, tray, etc. I sprayed commercial grade Lysol wearing gloves, mask, and my shooting glasses on the tray and both sides of the lower section of the coils, etc. Carefully wiped down the tray and found some black mold under the tray and in the tray near the drain. Sprayed that area heavily. Also saw dark streaks along the bottom area of the fins on the top side that I must have missed previously. Sprayed the bejesus there as well as I could reach. I also felt as much of the return air chamber as I could reach. No visible mold came up on my Lysol-dampened cloth. Gave a light spray to all sides of the return air chamber. We split and left the house for a few hours. It's going on 10 hours and everything smells half decent so far. Tonight will tell the tale! BTW: Great difficulty finding any AC company who actually want to touch the air handler section or do any hard work whatsoever! I don't trust any service people, got burned by several in the last 4 years here. OK, rant over. Another report may be coming.
Thanks, everyone, some great people on here!

[Topspinmo]

Sorry for the delay in getting back to everyone who was kind enough to give suggestions. I decided to use ServePro to inspect and service the ductwork. They create negative air pressure in the ducts and suck everything out to a big unit in the garage. Supposedly, ducts were then cleaned by a flexible air whip type device which doesn't harm the ductwork. I could not watch the process in the attic, old man here! I'm assuming everything was done as stated! The Tech said nothing found in the ducts but some original construction very light dust, etc. No moisture, dead animals, etc. Then everything was sprayed with a great smelling product through the air handler. All was fine for about 48 hours, then the odors returned! SOB!! OK, I opened the air handler and reinspected the coils, fins, tray, etc. I sprayed commercial grade Lysol wearing gloves, mask, and my shooting glasses on the tray and both sides of the lower section of the coils, etc. Carefully wiped down the tray and found some black mold under the tray and in the tray near the drain. Sprayed that area heavily. Also saw dark streaks along the bottom area of the fins on the top side that I must have missed previously. Sprayed the bejesus there as well as I could reach. I also felt as much of the return air chamber as I could reach. No visible mold came up on my Lysol-dampened cloth. Gave a light spray to all sides of the return air chamber. We split and left the house for a few hours. It's going on 10 hours and everything smells half decent so far. Tonight will tell the tale! BTW: Great difficulty finding any AC company who actually want to touch the air handler section or do any hard work whatsoever! I don't trust any service people, got burned by several in the last 4 years here. OK, rant over. Another report may be coming.
Thanks, everyone, some great people on here!

Thank you for follow up.

[villagetinker]

OP, I hope you had a discussion with ServePro for at a minimum a discount on the service call.

[Altavia]

They should have cleaned the coils and pan as part of the service.

Have them come back and finish the job now that you identified the source.

Our HVAC guys put a few of something like this in the pan at maintenance.

https://a.co/d/e7MpcI3

Do you flush the drain lines monthly?

Builder recommends hot water with a few drops of Dawn.

[Pinball wizard]

We have a musty, dank, heavy odor coming from all AC vents. The patio villa is less than 4 years old and is kept immaculate. We have UV lights above and below the air handler and an electrostatic permanent filter that is cleaned monthly. The AC works perfectly and everything visible is clean, but the odor is bad and actually burns the throat and eyes. Who do you recommend for checking the ductwork? We need a pro , not some rookie kid to diagnose the problem. Thanks in advance.

Depending on the air filter, some are not UV light resistant. You may need a UV resistant model of the filter.