I’m Kayla, and I get warm fast. Our bedroom felt like a toaster by June. The garage was worse. Quotes from local HVAC folks made my eyes water. So I tried the DIY route. Twice. Earlier, I’d tried cutting glare and heat with a bit of DIY glass film—tinting my own windows—but the mini splits promised a bigger payoff.
What I Installed (and Why)
- Bedroom: MrCool DIY 12k BTU, 4th Gen. It came with pre-charged lines, so no vacuum pump. I liked that part a lot.
- Garage shop: Pioneer 18k BTU (not a DIY kit). Cheaper up front, but I had to do real HVAC stuff. Vacuum pump, gauges, the whole bit.
We have a 1950s house. The bedroom is about 350 sq ft. The garage is near 500. Both needed quiet cooling and some heat in winter. Old framing also meant patchy insulation, so I’d already experimented with foam insulation DIY kits to plug obvious gaps before I ever mounted the indoor heads.
Tools I Actually Used
I used basic tools and a few “oh wow, I need that” items.
- 3–3.5 inch hole saw
- Stud finder, level, and tape
- Torque wrench (for line fittings)
- Hex key set
- Flaring tool (Pioneer only)
- Vacuum pump and gauge set (rented, Pioneer only)
- Electrical bits: 240V breaker, disconnect box, whip, wire
- Non-contact tester (to not zap myself)
- Lineset cover (line hide) and a wall sleeve
- Condenser pad and rubber feet
- UV tape and putty for the hole
I also grabbed a cheap pump sprayer with soapy water. I used it to check for leaks on the Pioneer flares. Old trick from a neighbor who used to fix soda machines.
Story One: The MrCool Bedroom Install (The Easy Win)
I started with the MrCool because I wanted a “no vacuum” job. I read the manual twice. Then I ignored one part and had to start over. Classic.
- Mounting the indoor unit took about 45 minutes. I went slow so the bracket was level. If it’s not level, water can drip on your wall. Ask me how I know. Yep, I had a tiny drip. I re-pitched the drain line so it sloped down and the drip stopped.
- Drilling the hole through the wall felt scary, but it was fine. I used a wall sleeve so the lines wouldn’t rub on wood.
- The lines were pre-charged. That saved a lot of fuss. I hand-threaded the fittings, then snugged them with a torque wrench. MrCool says not to over-tighten. I followed that and crossed my fingers.
- I opened the valves with a hex key. That’s the moment it feels real. I waited ten minutes, then started it up.
It took me about five hours, with breaks and a snack run. The bedroom cooled fast. On low fan, it’s quiet. I measured 25–28 dB near the bed with a phone app. That’s “library with soft whispers” quiet. My kid fell asleep through it. The outdoor unit was like a calm box fan.
The app? Eh. It works. But sometimes it lags. The remote is the real MVP. I use “Sleep” mode and “Dry” mode when it’s muggy.
What it cost me:
- Unit and lines: about $1,600
- Electrical parts and permit: $300
- Lineset cover and pad: $120
Total: around $2,020
My lowest quote for a similar setup was $4,400. So I felt good.
Story Two: The Pioneer Garage Install (More Work, More Learning)
I went cheaper for the garage. This one did not come ready for an easy push-button start. I had to flare the lines, vacuum them, and check microns. I rented a pump and a manifold. I also borrowed a micron gauge from my neighbor, Luis. He’s a saint.
- I mounted the head, drilled the hole, and hit a mystery nail. That set me back thirty minutes and one bad word.
- I ran the drain, but the wall was interior. No clear downhill path. So I installed a small condensate pump. It kicks on with a soft buzz and sends water to a sink line. Works fine.
- The flares took patience. I cut and flared, used a little refrigerant oil on the flare face, and torqued to spec. The torque wrench felt fussy but it saved me.
- Pulling a vacuum: about 45 minutes to reach roughly 500 microns. I let it sit. It held. That felt like a win.
- Opened the service valves, checked for bubbles with soapy water. No leaks.
It took me a full Saturday and half of Sunday. The result? The garage got cool and dry. Tools no longer feel damp. In winter, the heat amazed me. I wore a light hoodie and worked on a wobbly chair project without shivering.
Cost:
- Unit: about $950
- Tools rental and bits: $180
- Condensate pump: $70
- Electrical parts and permit: $300
- Lineset cover and pad: $100
Total: around $1,600
A pro quote for that space? I had one for $5,200. That made me brave.
How They Run Day to Day
- Noise: Bedroom unit is soft and steady. Garage unit is a touch louder but still easy to talk over. Outdoor units sound like distant wind.
- Power: My Sense monitor shows the bedroom unit sipping 500–900 watts most days. The garage unit pulls more under heat load. Our bill dropped compared to two old window units. Not magic. Just steady.
- Comfort: Temps stay even. No hot corners. “Dry” mode on stormy days is nice. Less sticky, less cranky.
- Heat mode: On cold mornings, the bedroom head blows warm air in about a minute. Not a furnace blast. More like a gentle quilt that doesn’t judge you.
The Good Stuff I Love
- Quiet sleep. Huge change.
- Real control. I set 73 and it holds 73. Imagine that.
- Bills that don’t make me wince.
- No big ducts. No dust storms in spring.
The Not-So-Fun Bits
- The MrCool app acts moody sometimes. The remote wins.
- Coiling extra line behind the outdoor unit looks messy unless you use line hide. I ended up buying more cover than I planned.
- The Pioneer install took grit. The vacuum step felt like a lab class. If you rush, you’ll cry later.
- Warranty rules can be picky. MrCool is DIY-friendly when you register. Some brands want a licensed installer. Read the fine print.
Should You Try It?
- Yes, if you’re handy and careful. You can drill straight, read a level, and follow safety steps. You can slow down when you feel rushed.
- Maybe, if you’ll hire an electrician for the 240V work. I’m comfortable with wiring, but I still pulled a permit and used a tester every time I touched a wire.
- No, if holes in walls make you panic or you hate measuring. No shame. A clean install matters, so get help.
If you decide a pro is the safer bet, the Service Center Team can quickly match you with skilled HVAC technicians who know mini-split systems inside and out.
Tips I Wish Someone Told Me
- Buy a lineset cover from the start. It keeps sun off the insulation and makes your wall look neat.
- Putty and a wall sleeve prevent ugly leaks and bugs.
- Keep a gentle bend radius on the lines. No kinks.
- Level the indoor unit with a tiny tilt toward the drain. A bubble level is your buddy.
- Don’t skip a disconnect box outside. It’s code and it’s just smart.
- Mark studs. Then mark again. My drill found the wrong spot once and got spicy.
- If you’re doing a non-DIY kit, rent a micron gauge. Don’t guess.
Real Numbers, Plain Talk
- Bedroom MrCool: about $2,020 all in. Took one long day. Cool and quiet.
- Garage Pioneer: about $1,600 all in. Took a weekend. Cool, dry, strong heat.
- Quotes I got: $4,400 and $5,200 for similar jobs.
I saved money, but I also spent time and nerves. That trade felt fair to me.
Little Moments That Sold Me
My daughter fell asleep during a thunderstorm with the MrCool on low. No rattles, no harsh blast of cold. Just a steady hush. In the garage, I sanded a cedar shelf for an hour in August and didn’t stick to the stool. My dog lay by the door and didn’t pant. Small wins feel big.
On nights when my brain still buzzed from torque specs and drain angles, I found it surprisingly soothing to chat with other LGBTQ+ DIY