Choosing between attic fan setups: roof or gable mount?

- Definitely agree on the leak risk with roof fans. I’ve seen a few “quick fixes” turn into long-term headaches, especially on older asphalt roofs. Once water finds a path, it’s tough to stop.

- Gable fans are just simpler. Less chance of messing up the roofline, and if you need to swap one out, it’s not a big ordeal. I’ve had tenants complain about noise, but like you said, at least you can get to it without risking life and limb.

- Insulation’s underrated. I’ve had a couple properties where just adding a few more inches in the attic made a bigger difference than any fan ever did. Not glamorous, but it works.

- One thing I’d add: watch out for negative pressure if you go too heavy on attic fans. Had a place once where the fan was pulling AC air right out of the house - energy bills shot up, not down.

- Mold’s a real concern in humid spots. I’m in the Midwest, and overventilating can backfire. Sometimes less is more.

- If you’re not re-roofing anyway, I’d stick with the gable setup and focus on sealing/insulating. Roof penetrations are always a gamble unless you’re already tearing things up.

I get the concern about leaks with roof fans, but I’m not totally convinced gable fans are always the safer bet. My house has a weird attic layout - gable ends are tiny, so airflow’s not great. I’ve read that a properly installed roof fan (with good flashing) isn’t much risk, even on older shingles.

“Roof penetrations are always a gamble unless you’re already tearing things up.”

I’ve seen a lot of attic setups where gable fans just aren’t practical, especially with those short or oddly shaped gable ends. If you’re not getting enough cross-ventilation, a roof-mounted fan can make a noticeable difference in attic temps. The key thing is really the install - good flashing, proper sealant, and making sure the shingles around the opening are in decent shape. I’ve put in a few of the newer low-profile solar fans on 15-20 year old asphalt roofs, and as long as the installer takes their time, leaks haven’t been an issue.

One thing to watch for: if your attic isn’t air-sealed well, a strong roof fan can actually pull conditioned air from the house, which isn’t ideal. But if you’re just roasting up there and don’t have a good gable option, I’d say a roof fan is better than nothing. Just double-check your intake vents (soffits or otherwise) so you’re not creating negative pressure. Not a perfect solution, but sometimes you’ve got to work with what the house gives you.

Can’t count how many times I’ve seen folks slap a roof fan on and forget about soffit vents - next thing you know, the AC’s working overtime and you’re cooling the whole neighborhood. Gable fans are nice if you’ve got the space, but those weird attic shapes make it a pain. I always tell people: air sealing first, then worry about fans. Otherwise, you’re just sucking money out through the rafters... literally.

I’ve run into the same thing - people assume more airflow means better cooling, but if the attic isn’t sealed up, you’re just creating a giant vacuum that pulls conditioned air right out of the house. I’m in a pretty humid climate, and I’ve noticed that when folks install a roof-mounted fan without proper intake (like soffit vents), they end up drawing moist air in through random gaps. That’s a recipe for mold and insulation headaches.

I’m curious if anyone’s actually measured the pressure differences after installing either type of fan. I’ve always wondered how much of an impact attic geometry really has on fan effectiveness, especially with gable fans in older homes where the attic shape is less than ideal. Has anyone tried using baffles or additional vent chutes to manage airflow, or is it usually just a matter of placement and sealing? Sometimes I think the fan itself is less important than making sure the air has a controlled path in and out... otherwise you’re just moving hot air around, not actually cooling anything down.