Spent yesterday redoing my dryer vent and found some sketchy stuff

Same story at my place, just through the wall instead of the soffit. My Kenmore electric dryer started taking two full cycles for towels, and I assumed the heating element was going. Pulled the machine out and found the previous flex duct pinched almost flat where the dryer had been shoved back too far. Swapped it for the semi rigid metal stuff and the drying time dropped immediately.

The vent run itself was about twenty five feet to the outside wall, and when I went out to check the hood, the flap was half stuck open with lint and a decent pile of lint had built up right at the exit. Pretty sure that flap was barely moving on its own, so the air had nowhere to go.

I ended up buying one of those rotary brush kits that connects to a drill and ran it through the whole run from inside. Pulled out way more lint than I expected, expecially around the first bend. Now I clean the run every spring and check that the outside flap actually swings open while the dryer is running.

One thing I learned the hard way, keep the flex section behind the dryer as short as possible. Mine used to loop down and back up behind the machine, and that low spot was where all the lint settled. Straight and short makes a bigger difference than anything else.

Funny how the vent gets all the blame, because mine turned out to be the dryer itself. Our LG electric was dragging through every load even after I cleaned out the duct run and the outside hood. Turns out the metal strips inside the drum that sense dryness were coated in a film from dryer sheets. Wiped them down with a little rubbing alcohol on a rag and suddenly the auto dry cycle actually stopped when things were dry instead of running the full time guessing game.

We had been using the timed cycles for a couple years because the sensor setting never worked right. Never ocurred to me that the sensor was just blind under all that residue. Same thing happens to the lint screen if you use dryer sheets a lot, the mesh gets a waxy buildup that water won't even pass through. Ran mine under the faucet one day and the water just sat on top of it. Scrubbed it with a soft brush and some dish soap and it drains fine now.

So if the duct checks out clear and the machine still acts slow, look at the sensor bars and the screen before assuming the element is weak. Ten minutes with a rag fixed what I thought was a dying dryer.

Reading this made me realize how lucky I was when I found ours. The vent on our old house didn't even make it outside. Someone had just run the duct into a corner of the garage and called it done, pumping wet air straight into the wall. No wonder paint kept peeling there.

Took a weekend but I ran proper duct out through the rim joist with a new hood. Whole lot less lint dust in the garage after that.

Not sold on pushing a drill brush through the whole run like the Kenmore guy did. All you're doing is shoving lint down the pipe toward the exit, and at a bend or a stuck flap it just packs in tighter. I tried that once and ended up with a clog worse than when I started, had to take the duct apart at a joint anyway. Now I pull sections loose and vacuum each one out by hand. Slower, but you actually remove the stuff instead of relocating it.

Update: the reply about dryer sheet gunk on the sensor strips got me thinking, so I wiped ours down with a rubbing alcohol cloth and sure enough there was a faint film on them. Also rethinking the drill brush idea now, the guy who ended up with a worse clog makes a fair point. Might just pull the soffit run apart again and check the bend by hand instead.