Finally pulled the trigger on heat for the sunroom after three winters of basicly losing that room from November on. Put in a 12k single zone unit, the indoor unit on the wall above the window, outdoor unit on a bracket out back with plenty of open space around it. Drilling the hole for the copper lines and drain, sloped down toward the outside, honestly took more measuring than the rest of the job combined. The copper was the part I was nervous about. My first couple of flares looked like a crumpled can so I cut them off and redid them until they came out smooth. Tightened every fitting with a torque wrench instead of guessing, then put the vacuum pump on for a solid hour and let it sit overnight to make sure it held before opening the valves. Had an electrician run the circuit so I can't speak to that side. Turned it on Sunday and the room went from 51 degrees to comfortable in about an hour, and it's been steady since. Been falling asleep out there reading every night this week.
Just finished my first mini split install in the sunroom and it's been running all week
Oct 14, 2026
Last reply: 6 minutes ago
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Did mine in the garage last spring, a 9k Midea unit, and the flare fittings were my whole personality for a week. I bought a cheap practice length of copper and burned through half of it before my flares stopped coming out lopsided. The trick for me was leaving the extra tubing sticking out past the nut and not overthinking it once I got the feel of it.
The vacuum pull is where people get impatient. Mine ran about 45 minutes on a small line set, then I closed the valves and watched the gauge for a couple hours like it was a stock ticker. If the needle moves at all, you've got a leak somewhere and it's almost always a flare.
One thing I'd add from my install: the drain had a spot where it sagged inside the wall cavity and I didn't catch it til the first humid week when water backed up and dripped inside. Had to open that section back up and re-slope it. Check that line with a bucket of poured water before you close up the wall, saved me a mess the second time around. Two winters in now and the garage stays at 60 even in January, which is all I wanted for my workbench.
Funny how the lineset hole gets all the attention when the drain is the thing that bit me. I put a 12k unit in my enclosed porch two winters ago and the heating side works great, but the first cold snap I came out to a sheet of ice under the outdoor unit. Turns out when these run heat, the outdoor coil goes through defrost and dumps water right out the bottom. Mine was sitting on a ground pad close to the house and all that meltwater pooled and froze solid around the base. I ended up shimming the pad so it tilted away from the unit and digging a little gravel trench for the runoff. Hasn't iced up since. If your bracket unit is out in the open like you said you might be totally fine since the water just drips into the yard, but keep an eye on it the first hard freeze. Also check where that condensate drain terminates. Mine dripped onto a paver walkway and turned it into a rink.
Sounds like the room itself came togehter quick though. Mine took me two weekends mostly because I kept second-guessing the routing, so getting heat in an hour after all that measuring feels like a win.
Nice reading about a clean first install. One thing that caught me on mine was vibration noise thru the wall bracket. Sounded fine at startup but two weeks later there was a low hum at night. Ended up putting rubber washers between the bracket and the wall and the hum disappeared. Cheap fix, wish I'd done it during the install instead of balancing on a ladder in February.
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