I don’t think it smells like seawage but before calling plumber I guess I need some more ideas as somehow it will be difficult to tell service person about the smell as you feel smell only when door is close for sometime. But it is bad smell. I don’t have AC nor any gas connection upstairs. Upstairs is only electric heating.

Not sure how to describe smell. It is kind of dirt/sewage smell as per my spouse but I feel kind of vomit smell once I enter the room. Once in 5he room for sometime don’t feel much smell as guess you are kind of used to that smell. We don’t have mouse in the area as not seen but we do have raccoons in the neighbourhood but I guess we will hear noise if that was raccoon. never heard any noise in the attic. We did ask a guy to clean the gutters recently and ask him to inspect the roof in that area but he didn’t find anything. Roof is only three years old and in good condition.

I will check attic in next week or so. Smell is always there whenever rooms door are closed.

Racoon poo smells like vomit, in my personal experience...

I didn't see where you said what the floor coverings were. If there is carpet, what's under them? Old pet smells in floors can remain for years, especially in wood.

You say the smell is worse when the rooms are closed, so I assume there are no lights on? I have read where old/faulty light fixtures can give off a smell when the lights are on.

About how old is the house?

I don’t think Racoon comes near the roof so it is mostly ruled out. Floor has carpet and I have literally put my nose on carpet and it seems to be ok. No pets. House is 23 years old. Didn’t find anything unusual in attic.

i did open the light fixture again and left the fixture open but it didn’t help but next day, I didn’t feel any smell (I think). Next day some families were visiting us so have to put back the fixture. I somehow feels that may be fixture is having smell though I don’t see anything wrong in it. Smell is there whether lights are on or not. I am thinking to change the fixture which is not completely enclosed.

Are there any drains you don't use very much? Like a shower that's not used for months or a floor drain? These can go dry (water in the S trap evaporates) and then sewer gas can come up into the room. Run water into all your drains that haven't been used lately.

Even if a vent pipe is clogged or plugged, gas can't come into the house unless there is an open pipe - either a dry drain trap or a vent pipe actually broken inside the walls somewhere.

If you suspect any critters in the attic, go in the room at night and knock on the ceiling with a broomstick. Then listen for something moving around. I had raccoons in the attic of a shed once and they would clump and thud all over the ceiling when I stirred them up. They'll tear stuff up to get in too, and poop all over the attic.

Attic looks nice. I am kind of zeroing on the light fixture but somehow both rooms have same issue does not make sense but I am going to try to change fixture soon. But for last couple of days smell is less.

My daughter had a bedroom that smelled bad, come to find out it was the insulation attached to the light fixture, the side that goes to the ceiling. The smell was awful and got much worse with the ceiling light turned on. I have seen other threads about this in the past.

MiMi, I think that is my issue too but I am still not able to buy new fixture as looking for one in which bulbs are not enclosed and also fit. I was just not able to get time or guess got lazy as smell is still there but little less. I will update the thread once I have an update to share.

Would you mind posting a couple photos of the light fixture... one with it open and one closed?

Also, are there other adjacent rooms that don't have the smell?

Do both rooms have the same light fixture?

Yes, adjacent rooms have same fixtures and both rooms have same smell issue. I will try to post the picture. I have bought new fixtures and intend to install soon as soon as I get some time in day time.

Make sure the bulbs are not too high wattage for the fixture. Fixtures have wattage ratings, should be printed on them.

Better yet, use a CFL or LED light. No heat, no off-gassing insulation, problem solved.

Want to say thanks to all. I think I have resolved this issue. I replaced both room fixtures last weekend and it seems smell has gone. Though their might be some residue smell but not that dirty smell anymore. I don’t see anything wrong in the old fixture but guess they are old and there was insulation on the back which might be reason of the smell.

Check above the rooms (under the roof) for dead animals in the attic. Squirrels and mice are common invaders.

If you have a chimney on an outside end-wall of the house and the chimney goes though the peak of the roof, that may be an entry point. Builders may frame the house and roof before the chimney is built (full brick chimney). After the chimney is built, there may be a gap where the eave box meets the chimney and the top side is bridged by roofing shingles, but underneath, the eave box does not meet the chimney. This is were squirrels entered my house. They got inside the eave box, moved down to the soffet (where the rain gutters are) and now had a lateral run the length of the house. They could enter the attic anywhere they pleased.

I know you said you sniffed the electric outlets, but....

Remove the covers and inspect them carefully, looking especially for any sort of scorching, warping, or other signs of overheating. Overheated outlets with a plastic body can smell pretty raunchy, and of course is a clear sign of an electrical issue that would need to be addressed.

^^ important info. There is an epidemic of sockets and switches slowly overheating and starting fires from high resistance connections.

If your house was wired with aluminum wire, do inspect the outlets and switches, and any other place where a connection was made by putting the wire under a screw head.