Burnt Offerings (1976)

"Up the ancient stairs, down the twisting corridor,
behind the locked door, something lives,
something strange, something evil,
something from which no on
has ever returned."
(The text on the poster)

This is a strange horror film from 1976 based on the book of the same title Burnt Offerings by Robert Marasco. It stars Bette Davis, Oliver Reed and Karen Black. Directed by Dan Curtis.
A married couple, their son and aunt look for a house to rent during the Summer holiday. They come across an enormous house. After they move in, there is something dreadful and mysterious about the house. 
I rate this a 7/10 for sheer weirdness. 

Howls ^^