Do you notice the diesel fuel smell in the house when you start the tractor in the basement.
I have never smelled the fumes upstairs nor has my wife. I do have a wall between the basment "garage" and the rest of the basment which probably helps.
As soon as the tractor starts, I give it maybe 15-20 seconds of run time then I slowly move it outside at the slowest idle and then continue to let it warm up for 3-5 minutes on a pad right outside the garage door so it's moved at most 15 feet. I have a gear tractor and it does not take much power to get it going.
When I bring it back in it's only running maybe 20 seconds at most in the house. I back it in at the lowest idle speed and as soon as it's in place it get's shut off.
I also park the tractor close to the garage door to help keep diesel fumes minimal.
What little fumes there are go away very quickly as I leave the garage door open for a short while to let it air out. My tractor is still "new" as it only has 100 hrs on it and there is just a short puff of smoke at startup and very little diesel smell.
Maybe this will change as it get's older.