Anyone else torn on where to route the exhaust hose from their K1 Max?

I'm in the carbon filter camp, partly because I'm in Alberta and the thougth of venting heated air outside for six months of the year hurt my soul. I built a box from a plastic storage tote with a couple of 120mm fans, a coarse prefilter sponge, a HEPA sheet, and a few kilos of loose activated carbon pellets instead of the thin mats. The pellets matter. The thin carbon sheets in most store-bought boxes saturate fast, but a deep bed of loose granules has way more surface area and lasts much longer before you notice smells coming through.

For PLA and PETG I honestly think you could skip most of this and just run a HEPA filter nearby. It's the ABS overnight jobs where the box earns its keep. I did a ten hour run last month and the room smelled fine, though I've learned to trust my nose as the maintenace schedule. When I can faintly smell styrene by morning, the carbon is tired and I swap in fresh granules. One thing I'd change second time around: make the box bigger and slower. My first version had fans screaming at full tilt and I suspect the air was blowing past the carbon too fast to get properly scrubbed. Now I run the fans at low speed and the air takes its time moving through the granules. Also crack the printer lid chain if you do ABS, since the K1 Max pulls air from the chamber and you want it flowing toward the box, not stagnating inside.

I actually went with a different kind of approach than the external venting or the big filter setup. My shop connects directly to the main part of the house, and I decided to run the exhaust duct into a dedicated hallway instead of opening a window. It kept the path internal, which helped me manage the heat retention issues I worried about with an external exhaust.

Total beginner here so take this with a grain of salt, but my situation is kind of flipped. I rent an apartment so the window is basically my only option, no room for a filter box anywhere. I got one of those window plate inserts with the adjustable zipper and just pull the duct out when I'm done printing. Winter hasn't been as bad as I feared since I only run it during prints, not all day. My worry is more that the hose adds resistance and the little fan behind the printer seems to struggle already. Does a long flexible run actually kill the airflow on these things, or am I worrying over nothing?

Following this beacuse I'm at the same decision point with my own machine, except my window is on the windy side of the house so I'm leaning toward the filter box idea too. The part about running the fans slow so the air acutally spends time in the carbon makes sense, I never whould have thought of that. My only concern is where you put the old carbon when you swap it out. Can you just toss the spent granules in the regular garbage or is that a whole other thing to figure out?

Quick update - I started putting togehter the carbon box setup. Since one person mentioned running the fans at a slow speed, I wanted to ask if anyone has seen the airflow drop too much when they throttle the fans down? Or if the filter effectiveness actually drops if they aren't spinning fast enough to pull the air thru the activated carbon media.