I have a whole house fan (a QuietCool ES-7000 that does 4,304 CFM/6,878 CFM) that is great for taking advantage of outdoor cool temps in the evening.  But I am pretty sure that it is being hampered by less-than-ideal attic venting, causing backpressure to develop in the attic when the whole house fan is running (which in turn, probably causes some of that hot attic air to leak back into the conditioned space–I know, I know, air sealing, it’s on the list…).

My roof is a series of hip roofs, so there’s limited room for additional turtle vents (we had the maximum of ridge vent installed, along with extra turtle vents when we re-roofed a handful of years ago).  The house (circa 1997 era) also has fewer soffit vents than it should, and I suspect (given the lack of insulation baffles in the attic at the eaves) at least some are buried in blown-in fiberglass insulation.

So, I’ve been thinking about installing a powered attic ventilator/fan to be used in conjunction with the whole house fan (looking at the Quiet Cool smart roof mount attic fan, rated at max of 2,116 CFM).  I know that the science says that powered attic ventilators on their own don’t work out to be a net positive and can create a host of other issues, but in this case I’m just trying to use it to get rid of the back pressure created by the whole house fan and wouldn’t be using it when the attic fan isn’t running.

So my question: Does this make sense, or are there drawbacks that I’m not thinking of?  Thanks!

Chris