Some residents share self-contained flats within the complex
The Salvation Army in Hull is giving guided tours around its building.
The open day is designed to dispel some of the myths and negative stereotypes surrounding the homeless.
Many people have the view of hostels as grim, Dickensian places.
To overcome this stigma the charity now refers to their homes as LifeHouses.
Graham Di Duca is the deputy manager at William Booth House in the city centre.
He said the name was chosen to encourage a positive state-of-mind for residents:
"We are about having fun and we are about people regaining self-respect and self-esteem, and finding they have a future."
The building was opened in 1984 and is a familiar landmark on the Hull skyline.
It has 113 rooms; some in self-contained flats and houses.
The residents are predominately men, with only 10% female occupancy. Contrary to the popular image of the elderly tramp, the vast bulk of the inhabitants are aged 25 to 40.
Mr Di Duca said that for most it was usually the breakdown in a relationship that forced them onto the streets:
Deputy manager Graham Di Duca:“We are trying to inject a sense of fun in staying in our buildings."
"They've had a home, they've had a family, they've had a job. But a combination of circumstances, maybe illness, losing the job, divorce and they find that their life has come crashing around them, and then they come here."
For many the hostel provides a safe place to start rebuilding their lives. Having a permanent address allows them to apply for benefit payments and the ability to register with a GP and get access to healthcare.
Many of the residents have addictions to drugs or alcohol. Being in a secure environment allows them to tackle their problems with assistance from specialist support workers.
The aim is to get people back into everyday life, with a home of their own.
Kev used to be a resident at the hostel. He now works as a volunteer. He said his experience helps him with his work:
"I know where the people are coming from, because I've been here myself. So I know how to treat them and respect them, because they're quite vulnerable some of them. Some of them you can have a laugh and a joke with them. I treat them with respect, and I get that back"
The building is open between 10:30 and 15:00 on Thursday 23rd September.
In the evening there will be a concert starting at 19:00.