How I finally solved the missing window kit problem — steps that actually worked

I actualy just finished printing a similar adapter for an older Black+Decker unit I salvaged for my garage. I used Overture PETG becasue, like you said, PLA just won't cut it. My exhaust temps were hitting 130 degrees Fahrenheit, and the first PLA prototype I made looked like a Salvador Dali painting after just two days of afternoon sun. I found that even with a good parametric model, the tolerances on those 5.1-inch hoses are a nightmare. I ended up adding a 2mm internal rib to the collar to give the hose threads something to bite into. Without that, the weight of the hose whould just pull the whole thing out of the window plate every time the compressor kicked on and shook the unit.

One thing I did differently was using a higher wall count instead of high infill. Four or five walls at a 0.6mm line width made the adapter rigid enough to support the ducting without needing any extra support brackets. It’s way better than the cardboard and foil mess I had going on last summer.

I’m just getting started with both AC maintenace and 3D printing, so most of this is over my head. I’ve been struggling with a loose hose for weeks. When you mention 'parametric' models, is that somthing a beginner can figure out easily, or do I need to learn how to design from scratch? Also, I’m curious about the hose weight. If I use PETG like you suggested, is there a risk of the adapter plate cracking if the hose is stretched out? I don't want to wake up to the whole thing crashing onto the floor.

Parametric's just a fancy word for "adjustable with numbers." Most sites let you just type in your hose size and it does the math for ya. I'd also grab some weather stripping. Even a perfect PETG print's gonna have tiny gaps where it hits the window frame. I stuck some 1/4 inch foam tape on the back of my plate and it finally stopped that annoying whistle from the air pressure. If you're worried about weight, just zip-tie the hose to a nearby table leg so it ain't pulling on the window the whole time.

If that window faces south, PETG might not be enought. I switched to Polymaker ASA for my Whynter ARC-14S setup because I've seen PETG get brittle after a full season of direct solar load. Also, check your thread direction before printing. Most 5.9-inch hoses use a counter-clockwise thread, but some older Royal Sovereign units go the other way.

I ussually add a 5-degree taper to the flange so it wedges into the window slider. It stops that vibration rattle when the compressor on a high-static 14,000 BTU unit kicks in. If you're using a dual-hose kit, space those ports at least 6 inches apart to prevent the intake from sucking in the hot exhaust.