Hooting is good. That is one way owls mark or claim this is my territory, stay out. Most owls are nocturnal and hunt at night.
If there is a mating pair of owls, they will hoot to communicate. Some owls make a screech noise to warn other owls to stay away or to ward off predators. Owls are one of the bird species that mate for life, or until death do us part.
How is the owl hooting? Is it like a hoot hoot hooooo..? That is normal for the Great Horned Owl.
As Flyingron stated, Owls sleep in trees, usually in a dense forested area. They can also stay in derelict barns or out buildings, hollow parts of trees or any small crevice in a rock formation.
One way to know where owls are roosting is to look around under the trees for pellets. Owls cough up something similar to a hairball. It consists of undigested material from meals. If you find one, pull it apart and you'll see bones, fur, feathers and possibly intact skulls of small mammals. It will give you a good idea of what the owl is hunting in the area as well as were it spends time after a meal.
Look for something like this:
And be sure to post some pictures..!!! (of the owl)