Quietest Oxygen Concentrator?

I am not sure a closet is a good place for a concentrator.
Some closets smell like shoes. Some smell like cedar or mothballs.
Others have the faint air of mouse.

The Oxygen needs a supply of clean cool air, heat is it's enemy. Also Quiet wouldn't be my first concern, Lifespan would if it was my money. They brought me out two new smaller units, one was noisy, the other didn't run right, they gave me a old noisy model it uses more electric but runs fine, that's why houses have more than one room. put it outside the bedroom, that keeps the noise and heat out. A 50 foot hose is the max. Jim

Power isn't a concern, just ask your for free electric... Jim