In my experience, a balanced system—soffit intake and ridge or gable exhaust—works best, but only if the attic is properly sealed from the house below.
I’ve run into this too. When I added more vents to our 1960s ranch, it actually made the upstairs draftier until I tracked down all the gaps around light fixtures and attic hatches. Air sealing made a bigger difference than any vent upgrade. If you haven’t already, try a smoke pencil or even just a flashlight at night to spot leaks—it’s surprising where air gets through.
Update Roof Ventilation ?
I hear you on the draftiness—had a similar issue in one of my duplexes after adding more roof vents. It’s easy to assume more ventilation is always better, but without sealing up all those little attic bypasses (can lights, bathroom fans, even wiring holes), you end up pulling warm air right out of the living space. What worked for me was going room by room with a smoke stick and some weatherstripping. It’s tedious, but honestly, plugging those gaps cut down on cold spots way more than any vent adjustment ever did. Sometimes I wonder if folks overdo the venting before tackling the basics...
I totally get what you’re saying about overdoing the venting—I fell into that trap last winter. I thought adding a couple more roof vents would help with moisture, but all it did was make the upstairs colder and my heating bill jump. Ended up crawling around the attic with a flashlight and a can of spray foam, sealing up every weird little gap I could find. It made a bigger difference than I expected, honestly. Curious—did you notice any issues with humidity or condensation after sealing things up? That’s the one thing I’m still trying to balance.
This is how the house looks today with one gable and what looks to be the bathroom fan vent next to it.
IF, I were to add another gable vent, it would be right next to it.
IF, I were to add another gable vent, it would be right next to it.
I see what you’re thinking, but honestly, putting another gable vent right next to the existing one doesn’t really do much for airflow. It’s kind of like opening two windows on the same wall—air just doesn’t move through the attic the way you want. The idea with attic ventilation is to get air coming in low (like soffit vents) and out high (ridge or gable vents on opposite sides), so you get a nice cross-breeze that actually pulls out heat and moisture.
I’ve run into this a bunch on jobs where folks thought “more vents = better,” but if they’re all bunched up together, it’s just not effective. Sometimes it can even mess with the bathroom fan vent, depending on how close everything is. You don’t want attic air getting sucked back into your bathroom, trust me... had a client once who ended up with a weird musty smell in their bathroom because of vent placement.
If you’re set on adding more ventilation, I’d look at whether you’ve got soffit vents or if there’s a way to get a vent on the opposite gable. Or, if your roof allows, maybe a ridge vent. But just doubling up right next to the old one? Not much bang for your buck.
What kind of climate are you in? If you’re somewhere humid or with big temp swings, good airflow makes a huge difference for shingle life and keeping mold out of the attic. If you can post a shot of the whole roofline or attic setup, sometimes there are options folks don’t think about at first.
Anyway, just my two cents from crawling around too many attics over the years...