HVAC company wanted $19,800, DIYed it for $1150.

Album: https://imgur.com/a/liyl8n1

I bet these mini split installs are a dime a dozen here on r/DIY, and I'd guess it's because HVAC companies are out of their fucking minds. That, or they're giving me the "I don't want to do the work" price. Either way, they're losing my business forever, along with anyone with a brain and some gumption. Same story as most of us here. Anyway...

We have this sunroom the previous owners added to the house--expanded the roof over a concrete slab and enclosed it in single-pane glass sliding doors. It has two temperatures: icebox and oven. The plan is to condition, insulate, and seal within reason, to make it usable on occasion for 3-seasons a year.

I received a couple quotes from HVAC companies for installing a 2-zone 24k heatpump that'd cover both the sunroom and garage it shares a wall with. Both wanted ballpark $20k. I've helped install a few DIY MRCOOL units in the past for friends & family that are running great years later, and so I knew that number was bullshit and was feeling angry and brave/stupid enough to try for a non-DIY unit to cut out the premium for pre-charged lines, and give me some tools and knowledge to maintain the system.

Some shopping later and I found a 12k BTU single zone 18 SEER Goodman (RXNG12AXVJU + FTXNG12AXVJU) from Heat&Cool for $399. Goodman was bought by Daikin some years back, and so their mini splits are just rebadged Daikin units. Mine even shipped from Daikin, and was badged as a Daikin. Manufacture date of 11/22, so it's been sitting a little while, hence the price. Probably trying to offload these older, less efficient units before R32 and the other next-gen refrigerants make R410a systems feel old, even if HVAC techs will carry R410a for the next 20 years. Efficiency doesn't matter much in my case, since it'll only be run occasionally, and we'll soon generate an annual energy surplus with solar.

Added another $750 in tools and materials, and I was set. I ran a 240V from a new 2-pole 15A GFCI breaker at my garage sub panel, up and across the attic to an accessible jbox, then down through [unbent...I know] EMT conduit to an emergency shutoff outside. Tried to do everything cleanlyish, but I welcome criticism, especially the "You're gonna burn your house down" kind. Also, you might notice that I compared the price of a 2-zone quote to a 1-zone; add another $1k and you're there, and you'd get Hyper Heat / low-ambient performance.

Mainly followed these two tutorials and leaned on ChatGPT for filling in the blanks:

Post Install Recap

$1150 was my all-in cost, including the materials to run power to the unit.

The pro install approach is really no more difficult of an install than the DIY kits, with the added benefit of being able to trim the lineset to size so you don't have this huge coil of lineset slack stuffed somewhere. You have to flare the lineset ends, add some Nylog, and vac the lines. All the rest is the same as you'd do for the DIY kits. The only real catch is that if you have to lean hard into the warranty they may press you to prove you used a licensed installer. It's a risk-benefit thing. This unit was so cheap, I could replace it 3-4 times before I spent as much as a similar MRCOOL DIY system. None of the warranties cover labor, just parts, so even if you have a DIY kit under warranty, if it's pain in the ass to disassemble and fix you'll be tempted to replace the entire unit anyway. Especially if it's been 5 years and everything is 25 SEER2 on R32.

Runs great so far. Can heat the sunroom to 65F when it's 25F out, which is far better than my initial hope for a range of 40-90. Still plan to blow some insulation into the ceiling, seal half the windows, and maybe add some rigid foam insulation on top of the slab when we redo the floor.

Hope this post gives someone else some courage to give it ago. It's pretty straightforward, very affordable, and relatively low risk to install your own heat pump mini split system.