I have 3rd car garage that has been re-purposed as a media room, and so I'm trying to see if a roof mounted attic fan will help reduce the temperature in this room during summer months. Some details about the garage and attic above: - Approx size - attic is for 3-car garage so roughly 20x30 or 600 sq. ft. - Garage is finished throughout with drywall - no exposed beams on ceiling or walls - There is a wall built out between the 2car and 3rd car portions of the garage - and a door of course. Also there is a 'fake wall' covering the garage door on the inside 3rd car part, which adds some level of insulation but is mostly there for esthetics - Garage ceiling is about 8.5' - The attic roof is pitched and at peak is about 4f't from the ceiling. - Currently there are no vents at all - there are 2 solatubes in the attic but nothing to drive hot air out of the space. The garage firewall separates the garage attic from the main attic for the house (which has several vents) - Garage faces due north, so primarily gets afternoon/evening sun - There is 'some' insulation above the 3rd car garage portion of the attic where I have the media room - I live in coastal Southern Calif The insulation in the 3rd car garage/media room walls/ceiling is definitely helpful, also this room is towards towards the inner part of the house and doesn't have an external wall taking the afternoon sun. I haven't measured the temperature difference but I'd guess at least 5-10 degree difference when the sun is hitting the garage in the afternoon - between the 2car and 3rd car portions of the garage. Anyhow - sorry for the details but thought I'd be thorough.. Any thoughts on how much temperature cooling you'd expect from one of these Roof Mounted attic fans is greatly appreciated

That was a catchy title, eh? :) I'm scratching my head as to why 2 motors both burned out the low speed windings on a 2 speed blower motor. One [b]new[/b] and lasted for a full 4 months with very light heating (low speed) operation, and a week of high speed (AC) before the "uh-oh" I smell smoke moment. Low side was burned out while in an AC mode. Weird. [i]Its a 30 y/o Bryant air handler unit with heat strips and an outside ground mounted (30 y/o) Whirlpool compressor that literally refuses to die. I've got great cooling.[/i] This [b]new[/b] motor was replaced in Jan only because of a bad diagnosis (slow blow fuse blowing), and I had the old motor (a solid 20 years old GE version) on hand that I pulled out at that time. I dodged the heat in the Phoenix attic and installed the [b]old[/b] motor again on Monday, and life is good. Only for a week. Then smoke. My local electrical motor shop was kind enough to confirm it was the low side on both motors that failed. I'm confident its [u]not low voltage[/u] to the supply box in the attic, that was the cause of the slow blow fuses failing from heat (not voltage spike) and have fully diagnosed the amp draw on the motor and the heat strips. The box failed to have adequate spring tension and the terminal lugs heated up, heating up the fuse. Box replaced, problem solved, no blown fuses. Separately, today I called Packard, who makes the fan relay that was replaced in Jan (only for sake of not wanting to climb up there again), and the old one bench tests fine. I've not bench tested the new (currently installed) relay, but after understanding the inner workings, it is probably not the culprit of what I feel is the root cause of motor failure. It just switches high and low speeds based on signals it's been given. It would have to fail in a "both circuits connected" mode, and that would surely cause immediate plumes of acrid insulation smell if that was the case. Agreed? [u][b]My hypothesis[/b][/u] is both the low speed and high speed are being activated at the same time. I have a Honeywell programmable (10 years old) Tstat. It has a definite heat or cool setting switch. Could it be somehow calling for heat (low speed fan) and cooling (high speed fan) at the same time (at random) if it has or is failing? I've band aided the problem by only hooking up the high side of the fan motor (#3), and what I heard today from the motor shop is that this is common for AC techs to do that to avoid fan failures, and return service calls on their dime. I'm 24 hours into this "new normal" of a one speed fan and no smoke yet. While I have plenty of documentation on the wires in the box to let others know what the capped off wires are for, I sure want to solve/diagnose the root cause of short motor life. How say ye of great knowledge? Wow, sorry for the long post on a Friday :Wink: