Direct drive fans should be designed for acceptable bearing life.
Belt driven vs direct drive whole house fan.
That would be quiet but would look like a mess from outdoors.
You have a fan a motor and maybe a coupling.
More often than not the maintenance cost of this kind of fan is also comparatively lower.
I fantasized building a small shack outside my house and setting the attic fan in the shack and running a duct up to the attic and through the same vent as an attic fan.
A well balanced direct drive is far quieter than belt.
With a belt drive the fan speed can be easily raised or lowered but there is belt and bearing maintenance to consider with a belt drive there are 2 additional bearings.
The second pulley is connected to a shaft that drives the fan propeller.
Unlike the belt driven fans in case of a direct drive fan there is lesser energy loss.
The two bearings on direct drive fan motors which are 7 horsepower and larger are typically regreaseable.
This is because of the fact that the amount of friction is greatly reduced in case of this fan when the fan is operating.
When compared to belt drive fans which require belts sheaves and bushings direct drive is just plain simpler and maintenance folks tend to lean toward direct drive for daily maintenance.
Sizing a whole house fan.
On both direct drive and belt drive fans the motor has two bearings.
Where on a belt drive fan the fan motor shaft has a pulley connected by a belt to a second pulley.
There s also no belt residue and these fans cost less to maintain generally speaking because belts don t wear down and break.
Belt drive fans have two additional bearings.
Most whole house fans are relatively easy to install.
Belt drive whole house fans that use an integrated pulley system take longer to install but a belt drive unit provides for a smoother and quieter operation.
It s incredibly hard to balance a belt and pulley system.
Direct drive fans are more efficient than belt driven fans 80 vs 60 direct drive fans cost the same as belt driven fans belt driven fans challenge the filters very much because of dust coming from the belt that guy was not a direct drive fan supplier.
Directive drive are louder but i think that will be the way to go for my mom s house basing on the information that you shared.
It s balance or lack of balance actually which causes most of the noise.
Belt drive fans are quieter than direct but still noisy.
Unlike belt driven fans there s less energy loss because there s a reduced amount of friction as the fan operates.
Greater efficiency is the biggest pro of direct drive fan configurations.
Direct drive fans have no power transmission loss since the propeller is directly connected to the motor shaft.