I just moved into a 10 year old townhouse. I found out from my home inspector that the previous owners were very untidy people. They hardly ever cleaned (I'm guessing they didn't at all) and they never changed the furnace air filter in the 5 year they owned the place (the thing looked like a giant dust ball). The vent fan in the master bathroom was broken, but my home inspector said he saw no signs of mold or mildew in the bathroom. The fan was replaced. There were lots of other little problems and a few major ones (garage door was rotting and sliding door seal broken and moisture got in).
The previous owners must have been using an air freshener (I think they had scented candles) because the moment I stepped into the door after they moved out I smelled a strange musty smell throughout the whole house. It's kind of hard to explain, kind of an "old dingy closet" smell. In addition the bathrooms had a "soap" smell to them, most likely because of all the soap scum on the tub. The water in the place has a mild taste/odor to it but not bad enough to explain what I'm smelling in the whole house.
The first night there I noticed my nose started to get stuffed up and my snot was slightly bloody. Over the next few days I've started coughing a lot and have had a runny nose. Today I feel somewhat weak as if I have a cold or flu (though I'm not coughing as much). Getting sick might have been a coincidence or due to stress, but I'm beginning to doubt that.
The previous owners had a tiny little dog (it didn't seem to smell) and a baby so I had the carpets steam cleaned with a truck mounted device. They put down deodorizer and use detergent and hot water. They did not use any sanitizing agent such as bleach or the like. Even after doing some areas twice the carpet was still discolored. I was told it was worn out and that it would have to be replaced.
I then had a cleaning service come in and do a rather thorough job of cleaning the place. They didn't wash down the walls or ceiling though.
Finally I spray Fabreese all over the house.
The smell went away (or was masked) for about a day and then returned. It seems worse in certain places like the master bedroom closet (there's a panel in there going somewhere, not sure where), one of the guest bedrooms and the storage closet in the finished basement (which raps around under the stairs and is partialy carpetted). The stairway down to the basement also smells, but that smells more like motor oil since the door to the garage is halfway down the stairs. The basement has carpetting and a "cardboard" tile ceiling (like you see in office buildings). I saw no sign of water damage at all, but the place was very dirty and the air intake vents were filthy.
Yesterday there was a damp dank smell to the place which seemed strongest in the basement and the master bedroom closet. It went away partially after opening all the windows and letting the house temperature go down to about 50 degrees F. I also left one window open last night.
I was told I can spray diluted bleach on everything, but that sounds drastic and has a potential to damage things. I've also been told I should get an allergenic (carbon) air filter for the furnace and to just run the fan.
My question is what can I do to get rid of these odor(s)?
Should I have my ducts cleaned out since the previous owner never changed the air filter?
Any ideas?