The ES-6400 pulls 6,320 CFM in a 20 inch throat – more than any other rafter mounted whole house fan on the market. And it is at an excellent price – lower in cost per CFM than any other.                       

The Thorwaldson Tornado ES-6400 is priced at $1795 and includes infinitely variable speeds. The only other like it is the QuietCool ES-6400 that must use two motors and blades and has just 4 speeds. It is priced at $1,849.00

Here are the technical specifications 

Air flow variable from 50 CFM to 6,320 CFM using a dial like a light dimmer. 

Input AC 120 VAC 1 Phase

Input AC power varies from 50 watts to 505 watts maximum at full speed. 

Unit comes in 3 parts 

  1. Main body with motor, blade and damper is 20 inches diameter by 23 inches long. It is suspended from two rafters using the supplied bar and hanger. It has an electrical box with a 6 foot AC input cord and plug plus a terminal for connection of low voltage thermostat wire for the 3 wire speed control. 
  2. Flexible HVAC duct is 20 inches diameter by 8 feet long.
  3. Ceiling mounted flange has 22 inch round white frame under the 20 inch diameter opening in the ceiling that has the 1/2 inch thick  cube core grille. On top is a 20 inch diameter duct collar for connecting the flexible HVAC duct.