Theo Smith's home for the past year has been a tent in a Woolloomooloo park and in that time he's made a few improvements, using a solar generator to run a small fridge-freezer, a kettle and a 32-inch TV.

But when it comes to washing his clothes, he has no such modern conveniences, usually having to line up at a local men's hostel or spend up to $50 of his pension at a laundromat.

"If you're not (at the hostel) early, you miss out," the 55-year-old said. "The other alternative is the laundromat but it costs a lot. I fill those stripey bags and it's between $40 or $50."

A free mobile laundry for Sydney's homeless to be launched on Friday will meet this most basic need, with the 21-year-old co-founders saying it will provide dignity and respect as well as clean clothes.