Of course I can't be certain. But I believe the clue to your issue is in your post. It is a new system. I suspect you are getting some residue burn off inside your air handler. If this is not making you sick and is more of an annoyance, I would not do a thing. Just monitor for the rest of the winter. If it doesn't go away by then, call your installer for a look see.

Since this is a new system, I really doubt you have dirty sock syndrome.

IMO

We have a year-old Trane gas package unit, and it seems we are also potentially dealing with dirty sock syndrome. We have been trying to figure this out for weeks, even had a plumber come out thinking it was a drain issue, but it's definitely coming from the vents. No leaks in ducts. The guys were out here today.

They cleaned the coils today and told us to monitor. If it's not better, they may have to replace the coils. Of course, it's jut out of the 1-year warranty, but we will argue about that. A unit that cost this much should not have problems one year out!

We are in the Carolinas, so definitely been a cold, wet winter.

This post was edited by gsciencechick on Mon, Mar 17, 14 at 14:07

Keep in mind that all ducts leak, it is just a matter of where and how much. If the leaks are external to the house envelope, you get pressurization or depressurization of the house. The depressurization can suck air in from outside in unpredictable ways.

You won't have DSS after you've been in heating mode for any length of time.

We started noticing this over the holidays. It is moreso when the system has been off for awhile. For example, on Sat we turned it off since it was in the 70's. I have horrible smell, and I could smell it in the late when the heat went back on. This morning when the system had run during the night it was OK.

Happy to report their treatment seems to have helped. We had the heat off since yesterday afternoon, and putting it on in the morning there was no smell.

We also had some plumbing work done the other day in the crawlspace, and I think that was also contributing to the smell. The smell was very strong after the guys left.

Yes, we are still having this problem. They put some sort of "cleaner" on the coils. The tech said it should help, and we should not be getting the smell when we run the A/C. We are still getting the smell with the A/C except now it smells like must and cleaner! It's like a Comet/Ajax smell

They said the only thing to do would be replace the coils, but it the heat isn't running, it can't be the coils, correct?

We are ready to call out a different company for a second opinion. We are beginning to think it's the ductwork.

All of you complaining about DSS (Dirty Sock Syndrome) should google Dirty Sock Syndrome and spend two hours reading about it. It does exist and Trane knows all about it. Problem is in the coil, copper pipes and aluminum fins in the newer hi efficiency models build up bacteria around the coil and give off a odor that can bother those who have a sensitive smell condition. My wife has a very sensitive smeller and continuously complained to me about the odor that I did not smell. After researching DSS I was convinced that was the problem and had the coil on my one year old system removed on April 11 to be sent off for a cleaning and coated with a epoxy that should eliminate the problem. At the date of this thread we have no odor, also no A/C, but the problem has been identified and is in the process of being fixed. My contractor has worked with this problem previously so it is not new to him. Update to follow after coil is reinstalled.

Kodak.1, in your research, do you see many reports of DSS when heat pumps are in the heating mode?

ionized:, I my case my wife smelled it when it was off or on. I've read some smelled it when you switched from heat to cold air. If you read all the articles on the Web you see some smelled it during the defrost cycle which only applies to the outside unit. I can only say, since the coil is out, my wife is not having the breathing problems she was having, and I am relieved. I do know Trane MFG is aware of the problem. Some folks have installed UV lights in the return air pendulum to clean the air and had good results.

FYI: The defrost cycle also applies to the inside unit. It switches the system into cooling mode so that the outside unit gets hot and the inside unit gets cold. To keep your house from freezing, it also activates the electric heating coils. After a few minutes it switches back.

Thanks, Kodak. I have been OOT the past couple days not online here. We have read some on DSS but could definitely read more. It will be interesting if your treatment helps. My DH is the sensitive one, me less so. However, I can smell it when I first walk in the house.

Major OOPS: Our system is a Lennox gas pack, not a Trane, but I'm sure the same problems exist. Our unit is exclusively outside; that is how everything is in our neighborhood.

I am almost thinking about contacting our local company and seeing if we can get a Lennox rep out here. I remember when we bought the system they offered to install the UV lights as an option.

We had a Goodman which is not considered a great brand, but it never smelled ever. The gas furnace portion is about the same efficiency as the old, so not that great.

It took awhile to get my coil back from Bronz Glow in Florida. It has been epoxyed and looks good. Installed today and already my wife can tell it does not have the odor it had before. Thank goodness for that. Amazing what you can learn by googling HAVAC odor or Dirty Sock Syndrome.

I don't understand why you'd have more severe DSS constantly in heat mode. One would think that the VOCs would blow off pretty quickly in heat mode and be gone as long as cooling is not used since no new growth will occur.

My understanding is that epoxy coating causes water to bead up and shed better. That would also tend to take soil with it. I am not saying that it is a bad move in this, but I wonder what it does to efficiency.

Too bad it would be too expensive to make an all-copper coil. The heavy metal would probably suppress microbial growth just fine.

Another theoretical solution to this kind of problem would be to blow outdoor air (filtered) through the unit when it is shut off for the day when it will not be run for several hours. That would dry the moisture out. I set up my car AC to do something like that.

This post was edited by ionized on Wed, May 14, 14 at 21:56

ionized_gw,

A+. You have the answer to the problem. The extent to which copper limits, when
compared to aluminum, the growth of bacteria is 99.99 % and the limitation of fungal
growth is 99.74 %. ("Characterization and Control of the Microbial
Community Affiliated with Copper or Aluminum Heat Exchangers of HVAC Systems";
Michael G. Schmidt, et al., 2012. DOI 10.1007/s00284-012-0137-0)(last paragraph). In other words, the smelly stuff can't grow on copper.

They should have gone to all copper instead of all aluminum
coils. But then they probably wouldn't
have been able to make as much money and what's a few sick people.

I had the same problem on my 1 year old Trane package unit. My contractor ordered me a new coil coated in epoxy and installed it even though it was out of warranty. Sweet guy! The Dirty Sock miraculously disappeared! However, I am now noticing a musty crawl space odor now that my unit is in the air mode. Very frustrating! My house is 5,000 Square feet, 21 years old and my other 2 older house units work perfectly with NO odors. Any suggestions?

Are your AHU or ducts in the crawl space? If so, fix the leaks. If the AHU or ducts are outside the house envelope, fix the leaks in the HVAC system and fix the leaks in your floor.

Thanks so much. The duct system is under the house. House is 5 feet off the ground. Maybe the duct tape has loosened under the insulation. Should I have the insulation removed and the tape checked? How often should his be done? I am concerned that fiberglass particles could escape and get into interior air space. My AC man did find a large piece of fiberglass on my coil when he checked it the first time for the Dirty Sock smell. He removed it, but not sure how it got there! Do you know is there a safer insulating material for duct work under a house?

Duct tape has no place in sealing ducts. You need to use mastic and mastic tape.

https://www.youtube.com/watch?v=aCCWAmESK4w

Sorry, that is what I meant to say! Maybe the mastic is old and coming apart. I have noticed some floor cupping during the hot summer months in the last three years.

I have a RUUD unit that is only 4 months old and dealing with DSS. They have sprayed the coils twice now and have a horrible chemical smell. My son has asthma and other medical issues. I can't turn the unit on right now because the smell is too strong. Do you think I can demand new unit?? thanks

For ario46 have them send the coil to Bronze Glow in Florida to have the epoxy coating applied. Stopped my DSS.

We had another company come out and do a treatment earlier this year. My husband was home, so I am not sure what they did, but it seemed to have helped. Of course, this year has been very mild and we haven't used the heat much.

There actually was a class action settlement with Lennox on this.

https://www.evaporatorcoillawsuit.com/Home.aspx

I don't think this lawsuit had anything to do with DSS. It was for defective coils that leaked due to the use of recycled copper and enhanced formicary corrosion. ALL manufacturers had this problem - that's why the industry has migrated to aluminum evaporator coils. Yes, copper is a more effective antibacterial; the jury is still out as to whether this will translate into more mildew growth problems.

A year and a half ago I kept noticing a musty funky order in the house, could not figure it out. That is until one day I was sitting across from the vent and we have a diverter thing on it so it blows out into the room. It hit me straight in my face. OMG it was bad. Made us both very sick and hubby had to go into the hospital because he didn't get better after having the coil cleaned. Well our awesome servicer put some pine oil solution on it and it appears it went away. We don't smell anything but no telling if there is some minutely as we have bad sinuses problems anyway. With his health problems I am looking at having the new coil coated by Broze Glo. But seems it is very expensive to get the indoor coil coated on our new heat pump we are getting. Trying to figure it out as with my husband's health problems we wanted to fix the issue before it could start again but the cost I am looking at is quite steep. Any help or suggestions?

There is a lot of confusion on this topic and in almost every single case of this I've seen, the suggestions are typically to treat the "symptom" rather than the true problem.

This comes down to diagnosis. If you don't diagnose the problem just treating the symptom will lead to return of the same problem.

Most cases depending on severity is typically due to over-sized AC system, however this isn't always the case. You can't confuse DSS with smells in heating mode, these are typically completely different problems. This is why your system must be diagnosed properly to get to the bottom of it.

If you suffer from DSS (dirty sock syndrome) cleaning or replacing the coil is only a temporary solution. 99% of the time it will come back.

Smells in heating mode are completely different and tend to be either dust / mold on heat exchanger burning off or on the electric strip heat strips. But as I said before, it must be diagnosed. Guessing is not a solution either.

proper diagnosis is the key.

How are they treating the health problems?

I notice it with my Payne unit sometimes as well. It's usually caused by the unit going into defrost mode, so I'm guessing the coils suddenly get cold and wet and it "wakes up" the smell for a moment. It also does it the first time I switch it to back a/c mode in the spring, but it lasts only about 5 minutes.

I FIXED THE PROBLEM. I have had this smelly problem for 10 years after a new heat pump was installed. Whenever the unit would go into defrost, the nasty smell would appear. At no other times was this smell present. This year the inside coil was replaced because it had a leak, but I was hoping this would fix the smell. It actually got worse with the new coil. After reading about this on many web sites, here's what I did. I closed off 1/3 of the outlet vents in my house. I did this in the morning with the outside temperature at about 40F (I had just noticed the bad smell again). The smell never happened again, even after several days when the night temperature was below freezing. So what happened? The articles I read kept saying the inside coil is the perfect temperature for the bacteria to grow. By closing of the air vents, the fan cannot push as much air across the inside coil, so the coil runs hotter. I put a thermometer into my air vents. When the smell occurred, the incoming temperature was 78F. With the vents closed, the temperature went up to 94F. The coil is apparently running hot enough to kill the microbes now. My house is 19 yrs old and I live in North Carolina. I have a Trane 3 ton unit and about 1400 sq ft of inside living space. 12 total vents and I closed off 4 of them. I also shut the doors to the rooms with the closed vents.

A heat pump coil in the heating mode will not be a good environment for microbe growth at any temperature. The growth will happen when in cooling mode between cycles when the coil is not at its coldest but cool and wet.

Incoming temperature was 94 after you ran the heat for a time wight the supply vents blocked? That means that the entire house was at 94, more or less. What was the supply vent temp?

I FIXED THE PROBLEM. More information: Outside temperature got colder and the outside coil
frosted up one night. A technician came out and said my unit did not have enough
freon (this apparently occurring when the new coil was installed). He said some technicians are a bit sloppy in filling the system
completely up - so he added freon and boosted my high pressure from 325
psi up to the recommended 360 psi. Now my system runs 93F vent
temperature (outside is 40F) with only two vents closed instead of the
previous four (all my doors are now open), the unit defrosts quickly and
the smell has still not returned. No problems during recently cold snap when night temperatures at my house were 10F.

I FIXED THE PROBLEM. More information. After a few weeks, the smell came back and the outside unit continues to frost up badly. So, the technician came out and said the unit was low on freon again (300 psi high pressure reading). So he put more freon in (back up to 350 psi). He also found a small leak in the outside unit and fixed it. The smell went away mostly. The unit goes into defrost much less frequently now with the freon added and only smells a little bit. But it still goes almost solid frost on the outside unit before the defrost cycle starts - so, something is wrong with the defrost cycle and it still has to be fixed. This smell may be a combination of problems.

If the days you smelled things were the coldest days, chances are the resistance backup/emergency heat came on and it always tends to have a short duration odor as the dust or whatever burns off.

I am the original poster from 2014!. There was a flaw with my particular model and Trane replaced the coils (I think) at no charge and the odor went away. I no longer live in the house and can't remember the details.

"info366863: But it still goes almost solid frost on the outside unit before the
defrost cycle starts - so, something is wrong with the defrost cycle and
it still has to be fixed."

Depends on what kind of defrost control, demand or timed. My lower-grade system is timed defrost and in freezing/wet ambient conditions it typically completely ices over between defrosts. I have it set for 90 mins of run-time IIRC because such conditions are rare here and it would defrost much more often than necessary in non-freezing conditions set at 30 mins. Your conditions may vary.

What I have learned so far: If you have a bad smell during the defrost cycle, have a technician make sure your freon is at its maximum value. It might be a simple/cheap fix. This has reduced my bad smell to the point I probably wouldn't have noticed it. (Now that I know it's there, I am alert to look for it when the unit goes into defrost.) To "d_gw": Maybe you had low freon int the system when you noticed the smell, and when new coils were installed, the freon was pumped up to the correct value. Just a guess.

info - freon was tested in my house before the changes were made. The smell was definitely a manufacturing issue.

d_gw - good point. Smell may have multiple causes or be a combination of things. If you have this problem, having system pressure checked may fix it or may not. It's just one thing to check.

My first ac unit I replaced was a Trane that lasted 5yrs according to all the AC Companies in Florida. I went with ahead in Oct 2014 and had another Trand(reck) installed. Six months after installation I started smelling something like wood burning or some irritating chemical. Original company came out and claimed nothing wrong. I had a friend who once worked with ac-units check the unit. Opened all panels and found water in the entire bottom of ac unit. He cleaned all but the fan with exception of blower due to heavy rains. I later had the lite mold removed. Smells continued and I had other AC Companies check unit. All continue to state nothing wrong & no sign of mold. I have had like 3-4 companies check the Trane with different stories. This month April 2018 had a new company check my home for air quality. He found the mold has gotten worse. I paid $2K to have mold cleaned and now also have an electronic air filter. Previously had another company that sold me an $800 purifier and my friend had earlier installed me a UV_Light. None of this has worked. By Friday night, 4/28/18 at 10pm the burning smell started. I had to put a fan in the window to pull the toxins out. I wrote this new company and will be having a visit this coming week to check ac unit again. I worry that I have been living with this harmful condition for over 3-yrs and what health issues are there in my future. I don't trust any of the previous companies and hope this new company finds the problem. As for the mold, if the first company had opened all the panels, they would of found the water and maybe none of this would have happened. I never had problems with the ac-unit until this 2nd Trane was installed. If I ever need to buy another, it won't be a TRANE. It is like this smell lingers in your home to a point you have to open windows. I get sore throats, itchy eyes and nose irritation I use Vicks to help me breath better. Thanks for reading...