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Thread: Increased VOC/dusty smell only when HVAC on

  1. #1
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    Increased VOC/dusty smell only when HVAC on

    Good Morning,

    I have had a consistent indoor air quality issue for about 6 months and mostly associated with increased VOCs only when HVAC on. Despite my making a sincere dedicated effort to find the cause(s), as noted below, it has been elusive. I would very much appreciate your help. Thank you very much for your review and consideration.

    Sometime during late last winter, I started to experience ‘dusty’ odor in my office. I subsequently cleaned everything, every square inch using a spray dust sol’n. I shampooed carpet with a product which I now know has VOCs and rinsed several times thereafter. I also cleaned inside desks with soap/water and unleashed a torrent of what I think was formaldehyde. I subsequently bought an Awair Home Element monitor and noted VOCs in in 10-30k ppb range in the desk drawers. Same thing occurred with cleaning inside bureau drawers. I moved the furniture to garage, bought two Airpura filters (F-614 and P614) and formaldehyde smell abated in following weeks. Furniture remains in garage.

    Although formaldehyde smell abated, I was getting the same “dusty” smell from the vents throughout home. Thereafter I made it a daily effort to clean every room in the house which is a ranch w/ walkout. The dusty odor persisted anytime I put the ‘fan’ or ‘heat’ or ‘cool’ on.

    I called a local HVAC contractor to do an air quality assessment. He recommended an Aerus Air Scrubber and a Dynamic electric filter which I had installed. NO CHANGE IN DUSTY ODOR, which btw causes eye irritation and irritates my asthma. He recommended that my ducts get cleaned and that was done late May. They used significant vacuum/HEPA in basement and went vent to vent cleaning. I looked at the filtered results and honestly there didn’t appear anything besides what you would expect in a home (dust, wood, cigs, etc). They subsequently sanitized with Envirocon. NO CHANGE IN DUSTY ODOR.

    The following day, I noticed a puddle of water below furnace. It was from a melted condensate pan. Had new evap coil installed. Why did condensate pan (believe it was plastic) melt? Had HVAC come out and check furnace and they said temps, everything were fine. I then sked for a full furnace maintenance check. I wanted to personally see the blower and make sure it was cleaned etc. Everything was fine. NO CHANGE IN DUSTY ODOR.

    I called a air quality specialist in to review the home and take air quality readings.
    Total VOCs were 1000 ng/L and
    Total Mold VOCs were 15 ng/L (Done by Prism labs and both were in moderate range).
    Formaldehyde was 83 ng/L (50-100 considered elevated). However, tech did not feel it was unusual as compared to many other homes he has checked. I subsequently did my own home mold check (Pro-Labs) and revealed Cladosporium and Penicillium. I didn’t know what to do with those results and didn’t pursue as I’ve not really had a musty odor.

    Two more HVAC companies came by and wanted to replace +/- furnace, a/c and ERV and whole home dehumidifier. My RH usually runs 42-55% this summer with 3 dehumidifiers. My CO2 runs 480-650 w/ windows cracked about an inch.

    You might ask how do I sleep at night w/ odor. My bedroom doors and vents are closed and I have installed port a/c.

    In summary, I continue to have dusty odor associated with inc VOCs when ‘fan’, ‘heat’ or ‘cool’ on. However, if everything is off and VOCs are elevated (500-700) I do not experience any odors….ONLY WHEN HVAC ON at any setting.

    Questions:

    1) What do you recommend in my attempt to find cause of increased VOCs/dusty smell when HVAC is on?

    2) Is there anything I should be considering to decrease the VOCs aside from running two purifiers and cracking windows a bit?

    3) Is there anything else I should consider re: melting of condensate pan?

    I appreciate this is a very lengthy post but I’ve tried to give as much information as possible. Please do not hesitate to ask for any add’l questions.Again, thank you very much. Vkaylar


    Stats:
    Home: Ranch w/ walkout, 1789 sq ft main level, 1200 lower
    Location: Des Moines, Iowa
    Occupant: One
    Furnace: Lennox G51MP-48C-090-07
    A/C: Lennox M/N XC13-036-230-02
    Evap coil: CAC/BDP CNPVP3621ALAAAAA
    Refrig: R410A
    Gas: LP

  2. #2
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    Aug 2021
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    Thread Starter
    I would like to post a followup which I find interesting. When my HVAC is now turned on in any mode, I do not get the VOC elevations as I had previously but get odor which again causes eye irritation and minimal changes in breathing. I have significantly increased ventilation with all windows open as weather better.

    So I guess the question remains - is the odor from ducts (recently cleaned and sanitized vs furnace/air handler? Any help very much appreciated. vk

  3. #3
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    How close is it to a floor drain or other plumbing drain?
    Check to be sure that there is water in the traps.

  4. #4
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    Aug 2021
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    Thread Starter
    Thank you Batman for your thoughts. I may be on to cause but I want to answer your questions:

    1) The HVAC is about 2' to floor drain. The dehumidifier and AC condensate pan drain into it.
    2) I have checked all traps in home and made certain there is ample water.

    Last evening I went into my 'office' room and got a sniff of exactly what I've been experiencing in the vents. As I previously noted, I had cleaned both those desks months ago and released a torrent of formaldehyde. However, after applying Enviroklenz to "seal" the formaldehyde and using a heavy duty air purifier (Airpura w/ 22# potassium permanganate activated carbon for formaldehyde) I had no further odors and VOCs in room were minimal. I kept the desks. However yesterday, for some reason or another I got a slight odor when walking through and it was from one of the desks. I restarted the purifier and today removed drawers to the garage. Desks will go as well. Today is the first day in ages I've been able to use AC and not have any eye /throat irritation, etc. So before I jump up and down and say the problems solved, I would like a few more days. I can put my nose to vents w/o any issues. The lesson I've learned is that you can clean up some items but formaldehyde is a pistol. I should have removed when I first experienced the odor. Thank you very much for your interest and questions. vk

  5. #5
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    Nov 2006
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    Leaking ducts? Especially the return, as that would draw in air from its surroundings.
    *********
    https://www.hvac20.com/ High efficiency equipment alone does not provide home comfort and efficiency. HVAC2.0 is a process for finding the real needs of the house and the occupants. Offer the customer a menu of work to address their problems and give them a probability of success.

    Find contractors with specialized training in combustion analysis, residential system performance, air flow, and duct optimization https://www.myhomecomfort.org/


    Site member map HERE!

  6. #6
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    Aug 2021
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    Thread Starter
    Thank you kdean. I appreciate your thought. Please refer to my email to Batman above. I have always thought about leaks in supply side for some reason or another and never return. I had seriously been thinking about having someone coming out to do a Duct Blaster like test for leakage. However, would that check return leakage? How does one know when they have leak on return side. My vertical components are studs/drywall and then silvery horizontal sections. So the bottom line is how would I assess both sides of the duct system? And if you found that there was a leak, how would a contractor be able to locate it?

    I have a ranch w/ walkout. No attic ducts just between floors.. I thought that when the duct cleaners came they would actually look through all the ducts but I was mistaken. So really the ducts have got to be assessed if odor recurs. My working theory is the formaldehyde. But I have to say I've been incorrect and humbled during the last 8-9 months. Thank you for interest and information. vk

  7. #7
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    It is possible to check duct leakage with a micromanometer. Supply leaks will depressurize the house. Return leaks will pressurize it.

    Try the HVAC2.0 link in my sig to find someone near you.
    *********
    https://www.hvac20.com/ High efficiency equipment alone does not provide home comfort and efficiency. HVAC2.0 is a process for finding the real needs of the house and the occupants. Offer the customer a menu of work to address their problems and give them a probability of success.

    Find contractors with specialized training in combustion analysis, residential system performance, air flow, and duct optimization https://www.myhomecomfort.org/


    Site member map HERE!

  8. #8
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    May 2022
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    Hi vkaylar - your problem sounds a lot like like mine. Did you ever get to the bottom of this or find a resolution? Thanks in advance!

  9. #9
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    Did you use Baking Soda or any baking soda containing product such as odor removers or carpet cleaners? It will cause exactly the symptoms you mention.

  10. #10
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    Quote Originally Posted by Jimmy111 View Post
    Did you use Baking Soda or any baking soda containing product such as odor removers or carpet cleaners? It will cause exactly the symptoms you mention.
    No, we have not used anything like this. No odor removers or carpet cleaning products.

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