Attics can be haunted. But, why? It's not as if anyone lived in the attic when they were residing in the house.
Let's break down some of the reasons attics are often reported to be haunted -
Explainable: There are many explainable things in the attic that can make one think they are haunted. Raccoons, rats, birds, and other creatures seek attics for shelter very often. As well, there are can be pipes and ducts through the attic that swell with heat and make noises. Some attics have vents on the ends of them which add the wind factor, riffling through and fluttering the insulation. And, lastly, most people store their off season and unused household items in the attic, often stacked in boxes, shifted around and shoved into place and forgotten, where they can move from the vibrations of the air-conditioning turning on or a rainstorm pounding on the roof.
Antiques: What do we store in the attic? Usually family heirlooms that are either too dorky to put in the house where people see them or other generations of things we have adopted as loved ones passed on. You set a bunch of items with a long history and lots of energies in a tight space with no exit - and does it build up? That is the big question!
Hiding place from the living: A natural retreat from the frenetic activity of humans is to find a place they do not visit. Like cockroaches and rats, a spirit might like to go where things are not being stirred up. This is a viewpoint held by many investigators. Noises in the attic might mean a lurking ghost. In the infamous book, The Exorcist by William Peter Blatty, early issues in the home involved scratching in the attic. It's easy to understand how sounds in the attic could be registered as a haunting, but first check out "explainable" above and then move on to the ghostly explanation. Attics are, after all, natural retreats for critters.
Trapped energy in peak of roof: In principles of Feng Shui, energy could be trapped in the peak of a roof and a room with no doors and windows to allow flow of energy in and out. That cul-de-sac space could harbor negative energy and allow it to circle around over and over in a kind of power battery.
The easiest ways to evaluate an attic are first to do a survey in the nighttime with lights and in the daytime of any critters, pipes, loose items, precarious boxes, and the like. Be sure you've covered all the usual culprits.
You might move on to clear out items, stabilize things that are up there, allow ventilation and light, and move antique items apart from each other where you can. Once you've cleared a good path to vents or windows, consider hanging a door mirror on the inside of the door facing into the attic. This can be used a shield of sorts of any energy that is trapped up there and is helpful in closet doors and basement doors, as well.
Movies involving creepy attics *Descriptions from IMDB*
The Skeleton Key A hospice nurse working at a spooky New Orleans plantation home finds herself entangled in a mystery involving the house's dark past.
The Changeling A man staying at a secluded historical mansion finds himself being haunted by the presence of a specter.
Crawlspace The Gates family dream house turns quickly into a nightmare when their life is disturbed by the deranged previous owner who plots to retake his home and the Gates children for his own - hiding in the house attic and methodically taking out all those that stand in his way.
Flowers in the Attic After the death of her husband, a mother takes her kids off to live with their grandparents in a huge, decrepit old mansion. However, the kids are kept hidden in a room just below the attic, visited only by the grandmother, and their mother, who becomes less and less concerned about them and their failing health, and more concerned about herself and the inheritance she plans to win back from her dying father, to the point of murder....
Black Christmas During their Christmas break, a group of sorority girls are stalked by a stranger.
Burnt Offerings A family moves into an old, haunted house that regenerates itself by feeding off of the life forces of its injured occupants.
Hider in the House A deranged man hides in the attic of a new house and becomes obsessed with the unsuspecting family that moves in.
The Sentinel Not ready for marriage, a fashion model moves into an unbelievably nice Brooklyn Heights apartment, where scary occurrences turn into a much more frightening turn of events.