I just moved into a new house as well, also a former rental before I bought it. My fiance hasn't moved in yet and won't for another month. I promised her I wouldn't sleep in our bed until she got here, so I've been sleeping in one of the spare rooms. There is nothing but a bed in this room at the moment.

I wake up at 4 for work. Around 4:45 on Christmas Eve I came out of the shower and walked down the dark hallway towards the spare room. I had left the light on and the door frame usually casts a shadow in a straight line across the hallway floor. I stopped because it wasn't a straight line but lumpy. I looked at it for about 10 seconds before the shadow slowly receded and the line was straight again. There was no sound at all. I went into the room and it was of course still empty.

I got dressed and went to work.

When I got home I played with the door a bit. I found that the door will not cast a shadow unless it is more than 45 degrees open, at which point you can see the door from the hallway. The angle of the door frame doesn't allow it to stay half way closed. If the door is not latched, it will very quickly swing to the fully open position.

So then I tried to recreate the shadow. This was easy. I went into the room and stood against the door, then leaned out to look down the hallway. Exact shadow I saw, but anyone in the hallway would have seen me leaning out. I slowly pulled out of the hallway and the movement of my shadow matched what I saw exactly.

I had a few cases of sleep paralysis 15 years ago where I would suddenly wake up and very clearly see someone standing over me. But this was 45 minutes after waking it. In that time I had a 15 minute video call with my fiance, taken a shower, and spent some time browsing Reddit. I was not even a little tired.

I was telling my mom about it and she insisted it was a car driving by. Impossible considering I'm on a hill with a thick wall of trees surrounding the back yard. I've slept in that room for a month now and no external light sources ever come through. I'm in the room now and I can hear lots of traffic on the road below, but the only light I've seen all morning is coming from my phone.