I usually go byt the amp rating on the back sticker of the fan.
ie: .06amp, .11amp, .19amp,
I don't know what the Delta black label has, the sticker is all black. But I have a similar Panflow that's .21amps and it's not that bad for noise. Right now I'm using a YS Tech fan (26cfm) that's good 2.
Remember though, the higher the amp rating the more CFM it puts out. (Cubic Feet Per Minute- of air) Find one that fits, and has a good (high) amp rating. AND you can live with the DBA's.
Good Luck.
