You’re spot on about airflow being the bigger culprit most of the time. I’ve seen tenants crank up the thermostat thinking it’ll fix a cold bedroom, but if a dresser’s blocking the vent or someone’s closed a damper halfway, it just throws everything off. Filters are important for system health and air quality, but unless you’ve got a house full of cats or someone with bad allergies, those super high-MERV ones can actually strain your blower motor over time. I usually stick with a MERV 8 or 10—keeps things clean without choking the system.
One thing I always check is whether return vents are clear too. Had a place once where someone stacked boxes in front of the only return in the hallway... made half the house feel like a sauna and the other half like a meat locker. Sometimes it’s just little stuff like that. You’re definitely thinking along the right lines—balancing airflow and keeping things unobstructed usually does more than swapping out for pricier filters.
One thing I always check is whether return vents are clear too. Had a place once where someone stacked boxes in front of the only return in the hallway...
Honestly, I get what you’re saying about airflow being the main thing, but I’ve had a couple old houses where the ductwork itself was the real villain. Like, even with every vent wide open and nothing blocking returns, half the system barely pushed air. Sometimes it’s not just “little stuff like that”—it’s leaky or undersized ducts hiding in the crawlspace making everything wacky. Had one tenant swear their bedroom was haunted because it was always freezing... turned out half the heat was leaking into the attic. Filters matter, but man, sometimes you gotta crawl around with a flashlight and just see where all the air’s running off to.
Had a job last winter where the upstairs was freezing and the downstairs felt like a sauna, no matter what they did. Folks kept swapping out filters and moving furniture, but it didn’t help. Ended up finding a huge gap in the main trunk line—looked like someone tried to patch it with duct tape years ago and just gave up. Half the heat was pouring into the crawlspace. Once we sealed that up, things evened out pretty quick.
Honestly, you’re right—sometimes it’s not about blocked vents or dirty filters at all. Old ductwork can be a real mess, especially if it’s been “fixed” by whoever had the house before. I always tell people, if you’ve tried all the easy stuff and it’s still weird, time to check where those ducts actually go... you’d be surprised how many times I’ve found them just blowing into a wall cavity or attic.
