Rafter Mounted Whole House Fan

The sources are in the order of highest performance first

Rafter mounted whole house fans are the most quiet of all because you cannot see them and you barely hear them. 


Thorwaldson Whole House Fan Company now has the highest performance attic mounted system, the ES-6400, that pulls 6,320 CFM in a 20 inch diameter body. The fan body includes a damper to prevent air falling in the winter.

In 2017 Thorwaldson introduced the first high performance rooftop mounted whole house fan. It is perfect for homes with no attics like those on mid century modern homes and the adobe  houses in New Mexico. Thorwaldson  systems all work with the X10 and Insteon PC and smart phone remote control for AC power. There is no remote control for speed.

Both of the Thorwaldson models off the highest performance based on one measure, air flow and power needed, CFM per watt. The ES-6400 is 12.5, higher than any other. The ER-8000 is 15.8 but since there are no other rooftops made, it cannot be compared. 


QuietCool has 4 product lines with  multiple performance levels in each. They range from 1500 CFM to 6,878CFM . The ES is their “EnergySaver” line that uses the new ECM brushless DC motors.  Their highest performance fan is the ES6000 at 12.25 CFM/W

Field Controls

Field Controls has released 3 lines of whole house fans, the VentCool Tahoe Series,the Summit Series and the Vista Series. 

Tahoe uses PSC motors apparently to enable lowest cost compared to the use of EC motors. The Summit has the modern EC motor and a gravity damper like QuietCool and others. The Vista adds a motorized damper which is a nice touch but they are not worth the extra money. 

The highest performance fan in their line based on CFM per watt is the 5.0 rated at 6,220 CFM at 825 watts or 7.5 CFM/Watt. 


The highest performance Airscape whole house fan is their 5300 that is rated at 5350 CFM and takes 825 watts to do that. It has more speeds than any other system on the market except Thorwaldson (Airscape offers 10 speeds, Thorwaldson offers infinite speeds). Since QuietCool and Thorwaldson fans both pull more air at less power and lower prices it is hard to  understand why Airscape would be a choice.

In 2016, apparently due to problems with remote control users turning their fans on without having windows open, Airscape came out with a pressure sensing system to inhibit their fans from operating without adequate window openings. Airscape is now also offering a temperature sensing and recording package.


This company offers fans with motors from Germany that they would hope you favor over American made fans. But the performance is not there. Their most powerful fan , the 4.0, is rated at 4028 CFM and takes 640 watts to do that.


Tamarack has 2 rafter mounted models,  the  1100  CFM and 2200 models.

All the rest are mounted on the ceiling.


I need to mention the Superfan. This fanpulls 1850 CFM fan with (4) 8 inch inputs from 4 ducts. This low air flow system is not competitive with the systems shown above. It is sold by various outlets but it has been impossible so far to find the manufacturer. 

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