I JUST WANTED to say that I live in an upstairs aparment and I have a horrible smell that comes through my vents...like sulfur or gas...it is so often that it makes me feel a little sick...Atleast three times in 24hrs it will blow out very strong through the vents..By tme U can get managment here the smell fades and they say we cant smell it...In my bathroom there is plastic pvc pipe and it sticks out into my shower right behind where my ac is where u change filters..this place has plumbing problems all the time/apt complex. Recently just right outside my section they did some plumbing work...this smell didn't start till afterwards...I am concerned because I don't know what it is and these people overr don't care to inverstigate it...it smells like gas...whatever it is I can't take much more.. I am single with a two yr old boy and I honestly think it is making us sickMy incle called the health dept but no word yet...does anyone have any advice...what is this how does it make us sick...what can I do...

Were previous owners smokers? We redid a rental house & got new screens, 2 coats paint on each room, completely redid the kitchen, new cabinets, countertops, new appliances, light fixtures, etc. New floors & new carpet throughout. As we worked of course it was fall & had windows open. Right after realtor started showing the house to renters it got cold & we had to turn on heat, wow, did the house stink, we opened up that furnace door & it was dark dingy yellowed smoke, stale stink. so hours more of bleach water & cleaners before the place was pretty good. We added bowls of vinegar at night & hid them in the morning. by the time renters moved in it was pretty good. So try vinegar bowls where kids & critters can't get at them Open box of soda in closed in areas might help. Take a vent cover off & wipe out area of vent & rinse rag out in clean bowl of water, is it all brownish? Then it's probably the vents, if it is just dirty water with no smell that might not be it. I took a long skinny broom to couple of my vents a few times, got almost nothing out but I had gotten a high quality duck tape for attics & seams & so I guess nothing get in them to speak of. I have allergies big time, also clean out the area under furnace where air goes into to it from hall. I put a heavy piece of carpet pad that is covered with plastic on the floor under there & then wipe out couple of times a year by taking vent cover off. Of course no 1 smokes in my house but that area does get some dust. Yes fridge, freezers & humidifiers have drip pans that need cleaning or they can make you sick. Also if you have any drains that don't have water in the elbow sewer gas can come up & make you very sick, is there drain in center of basement floor- be sure to put gallon of water down it often or keep it covered, upstairs bathroom not used, get water in all the drains including tub or shower. Good Luck, Hope you find the problem soon.

I'm having the same issue except I live in an apartment building with central air. Depending on what, where, how, when, why --- your apartment could be surrounded by other apartments, with other people and their living habits. Typically an apartment is separated by a sheet rock wall... there could be small cracks or gaps at the base of those walls, thru flooring possibly and or other possibilities. (They are often built *cheap* for the lack of a better more beautiful word that someone won't be offended by... *usually the builder or the apt. owner*) I say this because we might draw a builder into this conversation. LOL. (fine dining, fine accommodations, contractual obligations don't spell anything good for apartment owners.) When AC / Heat turns on in your apt. as well as other apts near yours the rooms of such are blown up like balloons and in some cases sucked into a vacuum drawing air anywhere from whence it can get it. If one apt is blowing and another apt is sucking? GIGO. Garbage In / Garbage Out... the net result is more or less smells collide among other things like odd noises. This is yet another reason why apartment living isn't for everyone. Not to knock you, but to give you context as to WHY?

That's a normal set up for a house with an addition. Is the smell inside the house our outside at the evap? How long was the house vacant? Have you changed the filters? Inspected the plenum behind the filter for dead animals? Generally a sour smell comes from decaying protein like an animal but it can also come from decaying plant materials. Animals are more likely. If you've already inspected all you can inspect, then it is time to call in a AC professional for an inspection.