We came home tonight to our 3 yr old house and there was a stale or gas-like smell in the house. Strangely enough, we don't have anything that is gas-powered. Our house is totally electric. The smell is very faint, and we only smell it when we go out, then come back in, but I can feel it in my eyes and my sinuses (although that could be my head playing tricks!) It does not smell like cat pee, nor does it smell electric. Still, it is bothersome. We have had this house since it was built, just a few years ago, so we are the only owners, and have never smelled anything like this before. Also, it may just be a coincidence, but each of our cats (we have two) have been ill recently, like sluggish and not interested in eating. Thanks for any suggestions you might have!

The odor is probably always there, but olfactory fatigue won't let you register it. That's why it would be noticeable after an absence.

I suggest a professional home inspection. There may be sewer gas coming in through improperly installed plumbing, wildlife in the attic/roof, or mold growing within your walls and floors. Mold in newly built homes is a big problem since the real estate bubble and fast construction. If this is the problem, you may have legal recourse to get the builder to pay for repairs.