Niwas is a Punjabi term used to refer to a place of residence or a place to stay. Commonly it is used to refer to the places for staying linked to Gurdwaras. When Sikhs and others visit a Gurdwara, most large temples will have places where the sangat can stay typically free of charge or for a small fee for one or a few nights. The accommodation is basic and there for the simple purpose of providing basic facility for a short stay while visiting a holy place.
This has been the traditions since the time of the Sikh Gurus.