Blocking off the gable vents after adding a ridge vent is one of those things that sounds counterintuitive, but it really does make a difference. I’ve seen a lot of folks assume more holes in the attic means better airflow, but like you said, air just takes the easiest route. If the gables are open, you end up with air moving sideways across the attic instead of pulling up from the soffits and out the ridge. That’s when you get cold spots, hot spots, and sometimes even moisture issues.
Baffles are underrated for sure. I can’t count how many attics I’ve been in where insulation is jammed right up against the roof deck, blocking off the soffit vents completely. No amount of ridge venting will help if there’s nowhere for air to come in at the bottom. Once those baffles go in and you’ve got a clear path from soffit to ridge, things start working like they’re supposed to.
One thing I’d add—sometimes people block off gable vents but forget to check if their soffit vents are actually open and not painted over or clogged with insulation. I’ve seen that trip people up more than once. Also, in older homes, sometimes there aren’t enough soffit vents to begin with. In those cases, adding more intake can be just as important as blocking off the gables.
I do get why some folks hesitate to close up gable vents though, especially in places with crazy humidity or older houses that “breathe” differently. But in most cases, if you’ve got a good ridge and soffit setup (and baffles), it’s usually the way to go.
Curious if anyone’s tried those powered attic fans along with ridge/soffit venting? I’ve seen mixed results—sometimes they help, sometimes they just mess with the natural flow and pull conditioned air out of the house. Not my favorite solution, but maybe someone’s had better luck...
Powered attic fans with ridge/soffit venting tend to be a mixed bag in my experience. When both are running, the fan can actually disrupt the natural stack effect and sometimes ends up pulling air from the conditioned part of the house, especially if the attic floor isn’t air-sealed well. I’ve seen cases where homeowners thought they were cooling the attic but ended up increasing their AC bills instead. If you’re set on a fan, it’s usually best to use it as a standalone system—not with passive ridge/soffit vents at the same time. Just my two cents from crawling through a lot of attics...