I felt a huge amount of tension as he was sneaking back into the house, groping through it, and finally heading down the stairs. Great buildup of suspense.
I also liked the phone conversations with his wife; they felt very natural and real, reflecting the history of their relationship without being weighed down by that.
It's a little odd that it's the basement was where his phobia was centered, since the trauma apparently occurred upstairs. But he was down there when he first heard the screams, and apparently he was always uneasy down there anyway, so it would probably be easier to displace the horror down there, and repress it, rather than having it centered on the upper levels where he'd have to deal with it while he was living there. It's pretty interesting how that worked out.