DIY Mini-Split Install: I did NOT expect this...

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[davidwalser]

In the summer of 2020, I installed a 12k MrCool mini-split in my detached 1-car garage-size shop. Then, in the fall, I asked our A/C tech to inspect my installation when he was doing the annual maintenance of our A/C units. I also asked him to shorten the lines for me. He charged me less than $100 to shorten the lines. Having the A/C professional check my work made this DIYer feel more comfortable.

The MrCool unit has done everything I could have asked of it. Even when it get above 115 degrees here in Arizona, my shop stays cool. My only regret is not doing it sooner!

[imasahm]

We installed a Pioneer (pre-charged in the condenser unit) about a month ago. We hired an electrician to add a breaker and shut-off and then he checked our install and all was great. We had never done anything like this before. We love the ease of installation, the quietness of the inside and outside units and how well it cools - our patio of 288sf has ten windows and a storm door and the unit cools it with ease. It's so nice to have a year-round usable sunroom now!

[RedwoodGeorge]

I self-installed a Mr. Cool 1 ton, 115 Volt in 2020 and it's been going strong for three years. Love that it both heats and cools so I was able to ditch the radiant heater in the winter. Setup is as easy as they say - if you've hung a flat panel TV on the wall, setting up the head unit isn't any more difficult. Both the indoor blower and the external evaporator are surprisingly quiet in both heat and cool mode; critical since I was cooling a home office and didn't want to ruin those zoom calls.

The one thing Matt didn't mention is that there's a teeny USB dongle that came with my unit (I believe it's standard) that connects the head unit to your local Wi-Fi and then you can control the cooler through an app on your phone. I find it very useful to set up a scheduled heat in the wintertime; I start heating about an hour before I get into my office and it's good to go by the time I get there.

[michaelhelton]

HVAC is going to be a very hot topic for the next few years. Great to see @buildshow tackle this from a DIY perspective. Protip: Before sealing up the penetration, put in some steel wool. Mice will eat through foam but the steel wool stops them.

[barryomahony]

This is in total response to the attitude of the HVAC industry and the monopoly their installers impose. Look at the online prices for minisplit components, and then get quotes for the same units for your friendly neighborhood HVAC installer. They typically mark up components by 100%, and then add labor on top of that. Yep, of course Mr. Cool is gonna jump in an exploit this ridiculous situation. And now you have respected Youtubers like Matt and April Wilkerson endorsing this. I plan to install a 2-zone 36K unit for the shop my wife and I share.

[drband]

This is totally doable for a diy person with good skills and some equipment. That said, I rather use a system with non-pressurized linesets— cut to proper length and no coiling. I installed a mini split in my garage workshop (app 400 sq ft) 16 months ago (9000btu) and have been totally pleased. I purchased all my needed install equipment (gauges, vacuum pump, pipe tools, nitrogen tank, special connectors, etc and still only spent less than $1500). I did my own electrical on a dedicated circuit and researched everything before starting. The system works perfectly for heating and cooling. You can do this. Don’t forget to weatherstrip a garage. Makes a BIG difference.

[nobster]

These mini splits are so easy to install that you don't have to be very skilled to do it. I'm surprised Matt is late to this topic, but Mr.Cool was featured on many of the other big name maker YouTube channels a few years ago, and nearly all of them have a DIY video for one of these mini splits. If you have some skill then take a look at their full size split system. I installed a 3 and 5 ton of their universal series on my house some years ago and they've survived multiple Texas summers and winters when many people's systems were failing. You don't need to do any refrigerant handling because they also sell pre charged lines but i went ahead and got the EPA's 608 certification because a child could pass it and it protects you from liability. I only did this after having multiple HVAC companies give me quotes over $50k to install equivalent big brand systems and that price just didn't sound right with how easy these electronics are to work with. Also, these smart systems are significantly more fault tolerant than the systems of old and a lot of hvac companies hate that about them. The old systems would simply let your compressor burn itself out with no warning that a problem was coming. These smart units will detect the faults long before they kill your system and the repair is much cheaper. I had to replace one board in my 5 ton after it shut down from an overcurrent fault. Contacted Mr.Cool and they knew about the issue with the board and sent me the replacement with instructions on how to install it myself. Don't take this to mean you can't get killed doing this kind of work, but it's not more dangerous than understanding electricity and moving heavy appliances so that they don't unalive you.

[seriouslee]

Would love for you to see my 1910 block farmhouse. I put in a 4th Gen Mr. Cool with 5 zones. Super cold. Stucco outside and inside of walls. Amazing how energy efficient from looking at my utility bill for a month of use. Increase was only $100. I did all the work and I am super pleased with the results.

[michaelmartin]

I have a 3rd gen McCool for my whole house, and it heats and cools my house, and my bills are great for what my house is. I did the entire install myself. I have 36k with 4 indoor units. 1300 Sq ft home from the early 1900s only half insulated. Will never go back to a traditional system.

[Memento-_-Mori-_-]

Me and my dad installed a similar unit about 7 years ago and it's still running like a charm.

[dukebeach]

Love that another monopolistic trade is under attack.
Had a company bid $22K for a new condensing boiler to replace an existing one. Found online direct for $4, 500.
Had a plumber come out to take a look at a leaking check valve on a sump line in the basement. Bid $450 to replace. Seemed absurd to me.
Did some research. Found a quiet check valve upgrade at Home Depot. Ordered online and delivered to home for $28.
Installed myself in about an hour and that was due to difficult access.
Trades need to realize that homeowners are tired of being ripped off and gouged.
Charge a fair price for a competent service.
Love to see more and more DIY products come online.

[ericapelz]

We put a Mr. Cool mini-split in our pole barn workshop, which is well-insulated, and it works great. It's worked great for over a year and kept the building at a comfortable temp all winter and summer.

[mattgirgenti]

I installed my Mr. Cool myself. I replaced my old heat pump with a Mr. Cool 2-3 ton Universal. Not 'super easy' but certainly not hard. Love that I can set heat and cool separately between 2 or 3 tons with dip switches. Outside condenser AND inside air handler. Takes some time and patience, but very doable. Hardest part is manipulating/running the line set. Called support once during the install they were very helpful.

I am about to do the 4-5 ton unit for other part of house. I am considering reusing existing line set since it is are already safely in the exterior wall and in good shape. I'll have my AC friend do an evac/recharge. Mr. Cool comes with the connections for him to do that as well. Really smart setup.

Pros!
- SUPER quiet units and very effective.
- Uses about 1800 watts when running. My old system used 4500-5000! NO power surge on start.
- Decided to NOT order heat strips with it. Not needed in Houston since the unit will work well down to 0 and at 80% at -20/ Super impressive!!
- Price. I spent under $4000 and about 8-10 total hours to do what a contractor quoted over $12000 for! Not knocking the contractor, and for those not willing/able to DIY a good contractor is worth their weight in gold. That said, Mr. Cool provides some really good options for replacement units.

Cons:
- Line set is very stiff and frustrating
- Line set is bigger due to UV cover and harder to "hide" on outside wall. Not very aesthetic, but can use traditional, smaller line sets if you prefer.

[brandonkruse]

Bought mine almost 2 years ago, it’s their universal series and it heats and cools the house perfectly.

[bretharrell]

I installed a mini split in my garage in Texas about 5 years ago. Best thing I ever did. I think I would still buy the type with non-pressurized linesets - thought it's interesting to see that a product like this exists. I don't have a big ugly coil on the side of my house like this, and I used that cover product they showed to hide everything. Very clean install. Hard part was drilling through the wall and bricks. I did have to pay an HVAC guy to pressurize the lines, but he didn't charge me very much. I did the electrical work myself - just added a breaker and researched the correct way to do the wiring - but then I've done quite a bit of wiring over the years. It made me laugh when they said to hire a licensed electrician as I think they're saying that to limit liability. I also did good weather stripping on the doors and added foam to the doors for some insulation which actually helped quite a bit.

[court]

I have read that you shouldn't coil the excess vertically like that. It traps the lubricating oil in it and destroys the compressor. It should be coiled in a spiral horizontally in a way that drains.

I'd like to hear Mr Cool weigh in on that.

[jimbecker]

I installed the 24K unit in my new shop building. Excellent system. Easy install. Totally satisfied...and $2500 compared to over $4000 from an HVAC company.

[davidhoover]

My HVAC technician said that those connections always leak. He said that walk in refrigerators have had those connections for decades and that they always leak he thinks because people DIY them. Word of caution to be careful there.

I decided not to go with Mr. Cool because they did not provide me with the specifications I needed to choose the perfect system. A lot of the Mr. Cool are rebranded Pioneers all from China! I went with an LG because it can ramp all the way down to 3, 000 btu barely running all the way up to 22, 000btu nominal and 30k btu peak. But, there’s no specs the company would provide me on the Mr. Cools I tried.

[waynr]

I was quoted $24k for a 5 unit system that really costs closer to 8k last year. I laughed out loud at the person quoting that price then when they started using my number to cold call me a few months later to offer the same system I told them to f off and never call me again. This weekend I'm working on the first of two 3 head mrcool mini split installs (including a 200 A sub panel in my garage that exceeds NEC code in a couple ways). I'm so tired of shitty contractors overcharging for sloppy work on my house so they can afford to drive unnecessarily large shitty pickups that get 4mpg.

[MelodiousSteven]

Installed one for my bedroom on a south facing room. Made a huge difference in the hot summers of California. Love these units!