We have a strange smell in our house. It builds up when my wife and I are out of the house for a couple of hours or more. If one of us is home, when the other comes home there is no noticeable smell. We both have to be gone. It is weird. The smell is kind of a stale, unpleasant smell such as you might find in a run-down, slummy apartment building, or maybe an older person's home who does not have the energy to take care of hygiene matters. It is not a sewer gas smell. It is not the smell of mold. The smell dissipates fairly quickly after we get back, often in a matter of minutes (we open the door for a few seconds, light candles, and my wife sometimes also lights incense). Even when we donít light candles and incense, it is hard to locate the source of the smell. It seems to concentrate in the entrance foyer, and then spread to the nearby living room and kitchen. We noticed that even before opening the front door, in the space between the storm door and the front door, there was a strong smell (we took down the storm door, but the smell remains). We moved into the house almost a year ago. It is a home built in the early 1960's; concrete block foundation; repainted before we moved in; previous owners were older and had moved into a nursing home before the repainting; no attic Ė just a shallow-sloped cathedral ceiling throughout the house; we have an early 1960ís oil furnace. We have a high water table in the area, and our sump pump always has some water in it (which does not smell). Our roof has been checked by a roofer, and our plumbing pipes by a plumber, and both are o.k. We have had our ducts blown out, and have put in new pleated, 3M filters. We have hardwood and vinyl floors (we ripped up the carpet). Does anyone have any idea what could be the problem? What could cause our house to smell (intermittently) like a slummy apartment building? I would be extremely grateful for any ideas or suggestions.