attic fan = belt or direct drive?
 

What are the pros and cons of belt vs direct drive in attic fans? I mean the kind that sit between ceiling rafters.

Thanks,
Sixto

I'd say direct. The chance most people will go into the attic to check the belt for maintenance are pretty small. Most would not even think of it until it stops working or the belt makes noise.

I've had a big (36") belt drive unit running for about 20 years. Variable speed switch (like a light dimmer) died years ago. Just put in regular switch and runs fine.

with a belt drive you can replace the motor if it wears out or the fan bearings if they wear out. with direct drive the motor bearings bear all the weight and stress. the belt seems like the way to go to me.

it will require a belt from time to time though.

tom w

The only advantage I see to belt drive is that the motor is off to the side so you don't hear it humming as much. That might be an issue if you are running it at night. The one in our house is belt drive and we've had no problems.

Big trick with an attic fan is to make sure there is a big enough opening to let all of the air out of the attic. If you have a 36" fan (little over 1000 square inches), you need 1000 square inches of opening from the attic to the outside. Otherwise, the fan is working on presurizing the attic instead of moving air.

We have a direct drive and you better have a window open when you power that sucker up or it bows the walls in. REALLY fast and noisey. Quit using it about 10 years ago when we got A/C. Just getting away from the dirt and pollen it pulled in was a big plus.:)

Thanks for the memory....growing up we had belt driven attic fans and they did the trick cooling the house down during summers in Fla, they lasted for years.

I installed the belt driven exhaust fan in my house about 12 years ago. Five years after installing it, I crawled up to inspect and oil. There are no oil ports on the fan or the motor and the belt looked unused despite being used most of the spring, summer and fall of those five years.

I'll fix it if/when it breaks.