I'm thinking of putting in Up-Dux to help air flow from my evaporative cooler. The idea (if you didn't know) is to duct from the living space into the attic, which allows air to flow into a room without opening windows.

The goal is to increase cooling without worrying about security and noise from open windows. I'd probably do this for only 1 or 2 ducts, and each duct is 900 cfm.

The question is, is that a bad idea? My concern is getting moisture in the attic. I live in Western Colorado where it's mostly dry and hot in the summer.

To prevent a moisture problem, I considered adding an attic ventilator, but I ran across Martin Holladay's article on GBA saying he's not a fan. After reading the article, I'm less confident about that approach.

Bonus question: Am I overthinking it? The evaporative cooler could basically serve as a whole house fan. So maybe it's fine to install some type of ducting into the attic from each room - whether it's the Up-Dux brand or not - and just close/seal those during the winter?

Thank you for any insight you have.

FYI the house is 1200 sq. feet. The attic is vented with 5 cap vents and 3 gable vents (the gable vents are old wooden ones, probably from the 1940s). Plus a few cracks here and there I'm sure... The evaporative cooler pushes 5900 cfm on high, but it's almost always on low. I also have a radon issue and a radon fan pulling from the crawl space.

If you can access the attic, why not just duct it the rest of the way outside thru roof or gable? If you tied these various room vents together, You could even put a fan/blower on it to enhance flow out of the rooms to help induce cooled air into the rooms via their doors...

Don't know that I would want to connect rooms directly to the attic space...

Thanks ronmar, I'm also not sure what I think of having the room directly connected to attic space. Supposedly those ducts have a spring damper that only opens when there's air pressure coming from inside the living space (or when the wind blows just right...).

I'm hesitant to take up an existing roof or gable vent (because I want to let them do their job?), but adding a new vent or two might work if I can make it look OK on the exterior.

My concern is getting moisture in the attic.

Moving air from the house to a warm attic doesn't create a moisture problem - relative humidity goes down as the air heats up in the attic. At night and with air movement, I'd expect the house temp and the attic temp to be close.