What is the name of 1970s or 1980s horror movie that not Elm Street movies and seemed to be low budget in which characters die if they go sleep possibly because their heads explode?

The movie you are thinking of is called "The Dorm That Dripped Blood" (1982). It is a Canadian slasher film directed by Stephen Carpenter. The plot revolves around a group of students at a women's college who are being killed by a mysterious force. The killer targets the students while they are sleeping, causing their heads to explode. The film is known for its low budget and its use of practical effects.