Mark22

I live in the 3rd floor. I have attic above me. It is a damp or spoiled smell. It makes me to cough to death. 2 weeks before rats broke inside my kitchen. They somehow figured out to make hole behind the dish washer. Pest control is working on it right now. I am moving to a different apartment next month. I suspect it to be mold or mildew. Apartment put merv 2 filter for months. I wasn't aware of it. Not sure if so much dust accumulated. When the temperature and humidity goes high, the smell starts coming out even without turning ON the system. I have sealed all the vents. I am done with it. It's been a nightmare.

Thanks for the info. I will get it checked.

i have the odor while running the AC cool as well. Not only during the heat. Do you think it will impact the cool mode as well?

I believe it uses water from water heater. When we had winter storm last year, water pipe broke and water service got shutdown. I had no heat for 2 weeks till the water service came back. Last month, Maintanance staff checked the water heater in the patio for any issue. Didn't find anything.

I have one for measuring indoor temperature and humidity. Acurite brand. I am from Texas. Right now Indoor humidity shows as 40% . Today - (40% Lowest 59% Highest)

Hello Everyone, I was looking online for some solution and i came across this forum. I have been living in an apartment for past few years. This January suddenly i started experiencing some kind of damp odor from all the vents. It comes out when using both AC cool and Heat. I had maintanence crew come in multiple times and also pest control. They said they don't smell anything. One of them was able to witness the smell, but couldn't figure out whats wrong. Odor neutralizing gel was placed near the AC filter. I myself bought HVAC odor block. But I couldn't stand that smell. And they don't seem to fix the issue. Sometimes the odor is very strong and other time it is very low. I am very sensitive to Odor/Scent and this gives me so much discomfort. I was using the air filter provided by management for past few months, i did some research online and found out it is MERV 2(Not efficient). I bought a new MERV 11 air filter. My apartment has no molds or pests. I keep everything clean all the time. I bought a new air purifier to see if that helps. I don't know what is causing this smell. Is there any fix you guys can recommend? Thanks , Mark