Yesterday, the electrician spent about four hours swapping out all five of the crappy old fans for these new, DC brushless motor fans. Very quiet, and far more stylish than the noisy old wooden five-blade fans. They have three blades and are shaped like an aircraft propeller.
Before the install. I handled one blade, noting it’s curvatures. Somebody got the blade design correct. I also happen to be a lover of anything aircraft, hence I wanted this blade style. The fans do the same job as the old fans, but far more quietly and with less rotation speed.