My attic fan is very loud. Is that normal?

Question

I just bought a house and it has an attic fan which is very loud. As far as I know it can only be turned off at the fan which is actually in a crawl space attic and I'm scared to go up there. Is it normal to sound so loud?

Can I have a thermostat installed so it goes off when it's cool? How much would that be?

Answer 1

The fan should have a thermostat already. It looks like a little metal box with a shaft that you turn with a screwdriver to set the temp. It should be located about 2 ft from the fan and has a shielded cable coming from the fan and romex ( white plastic covered wire ) supplying the power.  If it has just started to get loud, the motor is probably about to die. Often people set the thermostat too low or one fan isn't enough for the attic size and it runs constantly, resulting in shortened lifespan.

Answer 2

there are two reasons I know that would make it loud: either the bearings are worn and it is squealing (in which case you need a new motor) or the fan is not mounted properly and balanced so it is vibrating too much (which means you have to go up there, remount it (I would use rubber washers between the fan housing and wood framing to dampen the vibration) and balance it.

You can have a thermostat installed, which you should be able to get from your local hardware store/home center. You could also have an on/off switch run to where you can reach it. It is fairly easy and cheep to run a switch, as long as you have a fishing tape to get the wire into the wall.