Attic Whole House Fans

Hello, Kurt Shafer here, Founder and Inventor and President of Invisco. I am determined to bring you the best whole house fan you can find for your home. Unlike other whole house fan companies who talk about how their “company” has great products, I want you to know that I am talking here about the great products that I have personally invented for you and your home. Please feel free to call me with any questions on any fan. My cell is 951 296 3611.

First, I am proud to say I have invented some whole house fans the world has never seen before. Here is a good example. It is a big powerful fan that others sell for the purpose of installing it in a ceiling. But when it is in your ceiling you can see it and hear it make a lot of noise when it is on. Fans like this have been installed in homes since the early 1900s. Here you are seeing the first big 30 inch fan that I modified with a design to be installed up high in your attic so you can’t see it and you can barely hear it.

You can see that this 30 inch belt drive is installed with my custom duct box below it to connect 4 big ducts from 4 rooms to the big fan blade. This was installed in Temecula California. The fan blade pulls 6,400 CFM (cubic feet per minute) which will move all the air out of a 2000 sq ft home in 2 and 1/2 minutes!

Infinitely Variable Speed Control

I offer you the only whole house fans with infinitely variable speeds. This means you get to choose the air flow you want.

Remote Control Window Opener Keeps Your Home Secure

You have the option to purchase a remote control window opener that keeps out intruders even when the window is open and allows you to turn on your whole house fan from your smart phone any time from any where.


The Thorwaldson Tornado INA-6400 pulls 6,320 CFM with just one motor and it  is priced at $1595 and includes infinitely variable speeds. The only other fan like it is the now obsolete QuietCool ES-6400 that used two motors and blades and has just 4 speeds. It was priced at $1,849.00. QuietCool announced a new line for 2018 that has a big 24 inch fan rated at 6878 CFM called the ES-7000. But it takes 727 watts to move the air so the CFM per watt is a low 9.5 where as the INA-6400 does 12.5 CFM per watt. And once again QC exaggerates the flow – you can see they publish the HVI air flow but they say “for CA Title 24….” and that is NOT correct. The price for the ES-7000 is now $1,569.00 at Home Depot. That is 30 cents per CFM. The INA-6400 is 25 cents per CFM.

Below is an ad posted online on April 9, 2023 showing that QuietCool is still exaggerating the performance of their fans. The State of California Energy Commission fined QuietCool over $250,000 years ago for their false advertising. You can see below that they say the fan is 5,576 CFM but in the fine print they admit that the HVI-916 (Home Ventilation Institute test procedure required by California) is just 4040 CFM.

You can see it is perfect for hanging from your rafters. It has the damper built in to prevent cold air from falling through in the winter and it has the most powerful 8 bladed propeller ever used in any whole house fan. That is the reason it can move so much air with so little power. Just 505 watts at full speed and when you slow it down the power goes down.

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. 

Here is a nice install in Salt Lake City. 

Above is the fan hung from the rafters by Casey in Salt Lake City and below is the intake grille and frame Casey added in one room.