QuietCool is a respected brand in the whole house fan industry.
Its flagship CL-4700 receives 4.4 review rating on Amazon.com.
Pros: Powerful, beautiful, and quiet. Does its job well.
Cons: Pricey, missing key accessories (two speed switch, timer, 14/3 wire), too big to pass through regular ceilings.
Homequisite recommends this fan with reservations.
The fan is very quiet yet powerful. You can turn on the low speed all day (better evening time) long without noticing the noise except the cool and fresh air. This benefit alone covers up all the drawbacks below.
There are QuietCool branded two-speed switch plus a timer. But somehow there are not included in the $1200+ package. Moreover instead of attaching a 14/3 wire described in its own manual, it provides a regular 3-prong power cord which will have to be removed.
The price is around $1200, far above next level fan at $300 range. One DIY expert has devised a plan of similar caliber with less than half the price.
Please post your request in the comment section if you are interested in the plan. We will add a product link here if we get enough interests.