I doubt he is there, but just in case - and in order to make you feel better - a thorough physical cleaning is a good start. And I do mean thorough - clean everything! Floors walls windows baseboards cobwebs out of the cornsers EVERYTHING - with bleach if necessary, and if there is a rug, vacuum really really well. Just the act of cleaning is very powerful as far as clearing energy goes. After, burn some sage, with the windows closed so that the smoke really has a chance to collect in the room - then open some windows, maybe say a few words to the man - or whatever you feel is appropriate, and let the smoke clear out, taking any old and maybe stale or negative energy with it.
Then, once you get yourself settled in there, it would be nice to have a statue or cross or physical symbol of some kind that represents your faith or what you believe in, an item that comforts you and makes you feel protected. You could even set up a small area on a dresser top or small table, even a windowsill, where you can put the above item, and a few other things that have personal meaning to you. Get a few plants too, just to add some life, and continue to cleanse the air (spider plants, and I think golden pothos are both good for that, you can pick them up for low prices at Home Depot or Lowes)
Good luck in your new space!