I was working in the bathroom of an old century home, it was on the second floor and just beside the main staircase to the front door. The owner had bought the house for retirement and was renovating it before he moved in, he lived over 3 hours away. I was alone in the house and It was snowing quite heavily outside. A couple hours into the job the front door slammed shut and scared the shit out of me. No one should have been there so I went to check and no one was there, I opened the door and the snow that had blown against the door was not disturbed, no foot prints in the snow, no vehicle except mine and no tires tracks in the snow as mine had filled in. No wet foot prints on the inside either. That door had not opened but slammed hard enough too shake the house. I have no explanation for that, I was in that house a lot and that was the only creepy thing I ever encountered there.