when I was in my 20's I rented the top floor of a house from a very old man in his 90's, his rooms were a bit of a timewarp, but he lived on the ground floor and rented out the top two floors. We renters shared a bathroom but had our own sitting room, bedroom and kitchen.
We paid our rent fortnightly. It was the day my rent was due and I was in my room and suddenly knew he had died. There was a definite sense of the presence of death, not scary, not an absence, but I knew. I went down with the rent book and knocked on his door, no response so I opened it and he had died peacefully in the chair, cat on his lap.
I rang the police and an ambulance came, confirmed he was dead, but we had to wait for the coroner's van to come and take him. I was upstairs with the policeman, having a cup of tea, when I heard the other lodger, in her flat, on the phone to the police.
She had come in from dropping her son at school, when she opened the door had immediately known the landlord was dead, checked on him and got straight on the phone.
It was my first experience of death - she had been a nurse and said that she just recognised the atmosphere in the house when she came in.
I have to say it was a really positive experience for me and made me much less fearful of death, the atmosphere was very calm and positive, in my mind it was like he was hanging around to say goodbye to the place (he'd been born there). But a definite sense of someone/something not an absence of anything.