Just finished the sunroom AC setup — a few observations

I did a similar setup last summer with a Midea Duo 12,000 BTU unit when my central air died. Moving that compressor out of the living space is the only way to go if you actually want to hear the TV or have a normal conversation. I used a custom-cut plywood panel in the sliding window to bridge the gap for the insulated duct. One thing I noticed was that even with the insulated 6-inch line, I was losing a few degrees of cooling power over an eight-foot run, so I ended up wrapping the duct in extra R-6 foil insulation to keep the air crisp. My sunroom isn't as well-insulated as yours, though. On those humid 90-degree days, the ambient heat in the room started making the unit's casing pretty hot, which forced the inverter to ramp up more than usual. For the winter side of things, it works well until it hits about 35 degrees outside. After that, the heat pump efficiency drops off, and it struggles to keep up with the drafty windows. It's a solid middle-ground solution, but I’d definitely keep an eye on your electricity bill if the sunroom gets too baked during the day.

I acutally tried a similar setup with my Whynter ARC-14S last summer, but I ran into a massive hurdle with the unit's internal thermostat. Since the machine was sitting in my 95-degree sunroom while blowing air into my 74-degree office, the onboard sensors kept thinking the job wasn't done, even when the office was freezing. I had to rig a remote thermal probe to trick the inverter into cycling down properly, otherwise, it just ran at max capacity untill the coils frosted over. Another thing to watch for is the static pressure on that 6-inch ducting. I found that once my insulated run got longer than about four feet, the blower fan struggled to push enought CFM to actually cool the far side of the room. It ended up being alot of extra wear on the motor. I eventually moved the unit back inside and just built a sound-dampening enclosure around it with some Roxul board. It isn't as silent as having it in another room, but the cooling performance is much more consistent now that the unit is sampling the actual air it's supposed to be treating.

I had to deal with the drainage situation when I moved my unit out to the porch. On humid days, that condensate tank fills up fast. I ended up running a permanent gravity drain line through the sunroom wall so I didn't have to keep lugging the unit to empty it. It’s way better than relying on the self-evaporative feature, wich ussually can't keep up when it's pushing air through a duct. Also, watch out for the duct length. I kept mine under four feet to keep the airflow strong. Any longer and I noticed the fan struggled to push enugh CFM to actualy cool the far side of the room.

If you're worried about the inverter ramping up too hard in that sunroom heat, you shoud check out the LG LP1419IVSM. I’ve got one and the ThinQ app actualy lets me override alot of the auto-sensing mess that happens when you duct air into another room. It’s way more efficient than the older dual-hose units. Plus, the compressor is dead quiet so your sunroom stays usable even while it's working. Just make sure you get the 14,000 BTU model to handle the extra thermal load from the ducting run.

That's a smart play. I'd just make sure you're keeping those filters spotless. Since it's out in the sunroom, it's gonna suck up way more dust and pollen than it whould inside. If the intake gets even a little clogged, the inverter's gonna work overtime and kill your efficiency gains. I'm curious though, how're you handling the air pressure? If you're pumping air in, you gotta have a way for it to cycle back out or you'll just be fighting a losing battle with static pressure.