New build mini split: Mitsu vs Mr Cool

[HotRod68Camaro]

I'm in framing right now and my builder told me it would significantly cheaper if i did the mini split install myself on the garage instead of paying the AC guy to do it. The AC guy told him minimum $3500 installed for a mini split in the garage.

The garage is 980sqft, 10' flat ceiling all the way across, spray foam on all sides and ceiling of garage, insulated doors. I need at least a 40' line set from handler to condenser. I'm looking at the 23,000 or 24,000 BTU units from Mr Cool. Still trying to figure out my options with Mitsubishi, but they don't seem to be as DIY friendly as Mr Cool. I'm in central Texas, so I'm more worried about cooling capability that heating.

Here's the layout with the potential locations of the handler and condenser:




Suggestions, comments, concerns?

 

[Gigem]

I can't comment on installing them, but we had a Mitsubishi down in Port Aransas that worked great for a long time in a salt water environment. Seen Mitsubishi units all over Central America too.

Sent from my SM-G975U using Tapatalk

 

[shade]

Mr Cool DIY only has 25ft linesets.
With the advantage series you can get a 35 ft lineset.
You'll just need someone to come out and vacuum and charge the unit.
So far the MR Cool units are awesome.
I have 2 in my garage and will be adding a 3rd for the upstairs loft. Current unit just cant push enough cooling

You are close on your 40' need, maybe just slide the condenser unit a little more towards the garage door.

 

[HotRod68Camaro]

I was able to fine 50' line sets for Mr Cool online. Can't tell if they're precharged or not so I'm assuming they're not.

 

[My Old Tools]

MrCool works great. I did the DIY 25' line set. Easy, as in anybody can do it. Get the electrician to run the wire and set the disconnect and you'll be done in a few hours. Don't know if it's possible, but ask Ingram's if you can connect two of the 25' DIY sets together end to end. That would save you from having to vacuum the lines.

 

[theoldwizard1]

You are correct, Mitsubishi is NOT DIY "friendly". The install is basically the same, but I don't think the lines from Mitsubishi are "pre-charged". Maybe you can work a deal with your HVAC buy to evacuate and charge the system and submit the warranty paperwork ?

Bigger issue. In TX, with only one air handler, you will never be able to cool that whole garage adequately, even with all that insulation. You really need TWO air handlers, the second one at the far end and that is just too far from the condenser.

If you plan on running your line set out side, you will be losing a lot capacity. It really needs to be at the other end. Either behind some bushes or something else.

 

[Metallitubby]

You are correct, Mitsubishi is NOT DIY "friendly". The install is basically the same, but I don't think the lines from Mitsubishi are "pre-charged". Maybe you can work a deal with your HVAC buy to evacuate and charge the system and submit the warranty paperwork ?

My wife is the warranty manager @ Mitsubishi Electric (the HVAC group). This would technically be fraud if the contractor isn't the one who installed it, but it isn't like I would report someone for doing so.

 

[shade]

I was able to fine 50' line sets for Mr Cool online. Can't tell if they're precharged or not so I'm assuming they're not.

No only DIY series is 25'

The advantage or other series can be longer linesets but are not precharged.

The other poster mentioned about the air handler. I agree that the one air handler may not be enough.

 

[My Old Tools]

You are correct, Mitsubishi is NOT DIY "friendly". The install is basically the same, but I don't think the lines from Mitsubishi are "pre-charged". Maybe you can work a deal with your HVAC buy to evacuate and charge the system and submit the warranty paperwork ?

Bigger issue. In TX, with only one air handler, you will never be able to cool that whole garage adequately, even with all that insulation. You really need TWO air handlers, the second one at the far end and that is just too far from the condenser.

If you plan on running your line set out side, you will be losing a lot capacity. It really needs to be at the other end. Either behind some bushes or something else.

Actually, it works quite well with only one head centrally located. Mine is 30x40 and 22' to the peak. I set the inside unit at about 9'. Everything below that is uniformly cool.

 

[thammel]

I did Mitsubishi Mr Slim myself almost totally. I did pay an hvac guy $600 to evacuate and check out my 2 units. The lines aren't pre-charged but the units are. I poured the pads, hung the inside units, did all the wiring, set the outside unts; the only things he needed to do were connect, evacuate, do vacuum check and that was it. By the way, they are great units!

 

[Black Oak]

Do you have a HOA telling you where the condenser can go ? I would get it closer if possible . I don't have data warning of a line set "baking" in the sun all day , but I would minimize it if I could . Maybe use the biggest available line set covers , add some insulation for good measure . Also , if you can afford Mitsubishi , do it . It's considered the best by most out there .

 

[justinjoyal]

Bigger issue. In TX, with only one air handler, you will never be able to cool that whole garage adequately, even with all that insulation. You really need TWO air handlers, the second one at the far end and that is just too far from the condenser.

I disagree.

The garage is only about 36-38ft long and, well, it’s a garage, not a living area. I would not be concerned about slightly uneven temps as it is most likely not crucial for OP.

Would two heads be better ? Sure. But absolutely not necessary IMHO.

 

[yeldogt]

There is no problem heating or cooling that size space with a single point -- it's all about insulation and air leaking. Leaky doors would be a comfort issue if working next to them in the winter.

Don't mount the head too high -- with AC you just want do cool lower 6' .... no fans. Fans help in the winter to bring the heat off the ceiling ... not in summer.

 

[Mesozoic]

Agreed, a single indoor coil is capable of some serious cooling output. Minimizing line set length is a high priority. These modern ductless systems are simply amazing!

 

[HotRod68Camaro]

No only DIY series is 25'
The advantage or other series can be longer linesets but are not precharged

Ah, got it. I didn't see the details of which line worked with which series. I was only looking at the fitting/line sizes.

I did Mitsubishi Mr Slim myself almost totally. I did pay an hvac guy $600 to evacuate and check out my 2 units. The lines aren't pre-charged but the units are. I poured the pads, hung the inside units, did all the wiring, set the outside unts; the only things he needed to do were connect, evacuate, do vacuum check and that was it. By the way, they are great units!

That's essentially what im trying to do if i don't go with the Mr. Cool DIY units. the AC guy said he would do it, just waiting to hear back on how much he's going to charge.

Do you have a HOA telling you where the condenser can go ? I would get it closer if possible . I don't have data warning of a line set "baking" in the sun all day , but I would minimize it if I could . Maybe use the biggest available line set covers , add some insulation for good measure . Also , if you can afford Mitsubishi , do it . It's considered the best by most out there .

I do not have a HOA but it's personal preference on the location of the condenser. There will be absolute minimum lines necessary exposed. All lines will be transitioned into the wall cavity ASAP. I'm still in framing with no drywall and spray foam yet so nows the time to get it installed.

The garage is only about 36-38ft long and, well, it’s a garage, not a living area. I would not be concerned about slightly uneven temps as it is most likely not crucial for OP.

You guessed right. I'm not trying to cool it like a living space. I just want to keep the temps at a semi comfortable temperature. We've been above 100 degrees fairly regularly since the beginning of July.

 

[Jackfre]

The major brands definitely are not diy friendly. Mitsu produced the Mr Cool to tap that market, but they don't mix the two from a support structure. If you have a guy willing to do the start-up I'd go with the Mitsu. I've not done the comparison, but I doubt the diy product has the feature set that the Mitsu does. When locating your condenser I think I'd place the unit to the rt of the long closet window next to the doors. Don't worry about the aesthetics. They are mini-splits. The longer you live with them the better looking they become. With your 24 units location I'd run everything in the master closet and box it in for future access. Drain lines, which are critical can be a real pita in the wall. If you put it in the wall at least locate an access panel in the closet to be able to get at the connection. I would set it about 7-6 off the floor. That way it will not blow you over when you walk across in front of it.
That is a realy nice building!

 

[Git]

I also went with the Mr Slim in 2014. I purchased a 24k head dual head system from eComfort. I installed everything, including flaring the lines and then paid a local Mitsu contractor $300 to come in, check everything over, and do the start up for the warranty (leak test, nitrogen purge, etc). It's been 6 years and never had a problem. I wanted to get the condenser off the ground and out of the way so it is wall mounted and tucked under the eaves of the 1st floor roof

 

[yeldogt]

There is nothing more difficult with the Mitsubishi install vs any other ?

Guess with Mr. Cool selling various versions under the Mr. Cool brand name -- leads to confusion. Don't mix up the DIY units with the "regular" units that Mr. Cool sells. The DIY units have had post factory fittings installed on the head unit -- it's been evacuated and ready to go. Same with the line sets -- that's why you have to buy one of preset length and keep it. Or buy two for longer and get the coupling. Further confusion comes into play with the older DIY unit still being around with a line set attached to the head.

The DIY unit is obviously more expensive as it's had additional work done to it --- they also don't quite measure up in the cold operating levels to the better systems .... including other Mr. Cool units in the non-DIY model make up. The OP is in TX .. so no worries there.

I see a couple of things that go on in the industry. The better contractors with reputations -- sell the better equipment. So you are paying for the install and better equipment = more expense. They various ones I have run across don't want to deal with the perceived problems (both real and not) of the lower end stuff. It's Mitsubishi and Fujitsu -- with some LG tossed in. Plus -- now the big major USA players are using partnered products -- but they come with parts and support .. of the main brand.

The smaller independent HVAC companies sell on price and the less expensive units allow them to cut the overall cost -- they make a bit less on the install. Overall they can undercut the larger players. As many of us know -- some of the basic retrofit installs are very straight forward and easy ... especially on a garage where the compressor is in the back and the line set comes down the wall -- look are less important -- as is overall features and performance.

In general I think the installs are getting better as guys do more of them -- but I still see a lot of really bad ones!

Here is a pre install for one of my units (Mitsubishi) -- even with the space to be foamed we added the sheet foam to be sure it's not going to be short. We also had some block work adjustment on this part of the job (don't ask). It's not a basic install.

 

[830singleshot]

I would want it on the opposite wall with the condensing unit in the little corner between the garage door and the window. Simplifies everything. Drain lines and line sets are no longer a problem.
I tend to look at everything from the standpoint of what it takes to maintain it and it seems to me that the desired location introduces complexity, expense and maintenance issues.
I'm not a hvac guy but have had a lot of experience with lots of conventional split and a couple of mini's.
I would also talk to someone in the know about upsizing the unit. These things run so efficiently and throttle down when not needed but could recover much easier in our heat and open doors .

 

[My Old Tools]

The major brands definitely are not diy friendly. Mitsu produced the Mr Cool to tap that market, but they don't mix the two from a support structure. If you have a guy willing to do the start-up I'd go with the Mitsu. I've not done the comparison, but I doubt the diy product has the feature set that the Mitsu does. When locating your condenser I think I'd place the unit to the rt of the long closet window next to the doors. Don't worry about the aesthetics. They are mini-splits. The longer you live with them the better looking they become. With your 24 units location I'd run everything in the master closet and box it in for future access. Drain lines, which are critical can be a real pita in the wall. If you put it in the wall at least locate an access panel in the closet to be able to get at the connection. I would set it about 7-6 off the floor. That way it will not blow you over when you walk across in front of it.
That is a realy nice building!

I'm not sure what other features I would want. I control it with my phone (WIFI) from anywhere in the world. It has schedules you can set up. Several modes. Maybe there's something new?

 

[HotRod68Camaro]

I'm not sure what other features I would want. I control it with my phone (WIFI) from anywhere in the world. It has schedules you can set up. Several modes. Maybe there's something new?

What about door sensors? Any mini splits with that option? So they won't cool if either garage door is open.

Pricing out my options: Both of these prices are to my door costs of just equipment. service/evacuation/charge is not included in these prices. Both are ~24k units with heat/cool and 50' line sets.

Mitsubishi: $3600
Mr Cool: $2200

 

[My Old Tools]

That line set must be expensive. My 36k Mrcool DIY was under $2200 delivered.

 

[theoldwizard1]

I disagree.

The garage is only about 36-38ft long and, well, it’s a garage, not a living area. I would not be concerned about slightly uneven temps as it is most likely not crucial for OP.

You live in Quebec. OP lives in TX. How many days a year does the temp get over 35C ?

 

[justinjoyal]

You live in Quebec. OP lives in TX. How many days a year does the temp get over 35C ?

Yep, and I still disagree.

It would be better, just not *needed*.

 

[maswov]

That seems pretty expensive to me for installation, split type AC units are pretty straight forward.
I've never heard of Mr Cool but as far as Mitsubishi, that is what most AC techs recommend for reliability

 

[My Old Tools]

You live in Quebec. OP lives in TX. How many days a year does the temp get over 35C ?

Yeah, but I live in Texas and my shop is bigger. It works just fine.

 

[Mesozoic]

The longer the line set, the less efficient the system will be, so try to minimize that length as much as possible. As far as door sensors, you can tie into a home automation server to provide those triggers.

In terms of reliability, I may have experienced a botched installation: Daikin 24K + 7K coils and 3-ton outdoor unit, DOA. Professional installation by a reputable local contractor.

 

[yeldogt]

The longer the line set, the less efficient the system will be, so try to minimize that length as much as possible. As far as door sensors, you can tie into a home automation server to provide those triggers.

In terms of reliability, I may have experienced a botched installation: Daikin 24K + 7K coils and 3-ton outdoor unit, DOA. Professional installation by a reputable local contractor.

2 heads --- 31k on a 36k unit?

 

[Mesozoic]

2 heads --- 31k on a 36k unit?

That's correct. The 24K unit is spec'd to cool the shop floor (about 1700 sqft) and the 7K unit is in a dedicated 130 sqft office. The outdoor unit has 2 unused ports as well.

 

[yeldogt]

That's correct. The 24K unit is spec'd to cool the shop floor (about 1700 sqft) and the 7K unit is in a dedicated 130 sqft office. The outdoor unit has 2 unused ports as well.

My guess is it should have been a 30k unit .... that's quite a mismatch. What the turn done on the unit vs what the 7k room requires?

Why did not not work?

 

[Mesozoic]

From the calcs it shows that the main floor load is 21K and the office is about 6K, so not terribly off, but yes, slightly oversized.

The system was functional when first installed, but I do not believe they performed a soak test like I did for over eight hours. After several hours of run time, the system develops a sequence of error codes reported by the controller on both indoor coils and seems to indicate that perhaps the PCB in one or more of the units is bad. I’ve repeated the test 3 times and the only way to get them to reset is to power cycle the main breaker on the panel. The contractor has been notified and is trying to schedule repairs.

 

[yeldogt]

From the calcs it shows that the main floor load is 21K and the office is about 6K, so not terribly off, but yes, slightly oversized.

The system was functional when first installed, but I do not believe they performed a soak test like I did for over eight hours. After several hours of run time, the system develops a sequence of error codes reported by the controller on both indoor coils and seems to indicate that perhaps the PCB in one or more of the units is bad. I’ve repeated the test 3 times and the only way to get them to reset is to power cycle the main breaker on the panel. The contractor has been notified and is trying to schedule repairs.

My point is the two units add up to 31k and the compressor is 36k .... many of the compressors can do 25% .... that 9k ....more then the 7k head ?

Did they look at the tables and see if the 36k unit is designed for those two heads? Did they weigh in the charge?

 

[Mesozoic]

Yeah I do show a table that was given to me with highlighted rows that show the correct units for that 3 ton outdoor unit. The contractor Is reputable, but I think they sent a relatively inexperienced crew out to conduct the installation. This is evident, by the rough handling of the equipment and resulting damage, as well as missing parts, and several other issues I discovered when I came home from work. I would’ve preferred the A team, but it was a Friday...

 

[yeldogt]

Yeah I do show a table that was given to me with highlighted rows that show the correct units for that 3 ton outdoor unit. The contractor Is reputable, but I think they sent a relatively inexperienced crew out to conduct the installation. This is evident, by the rough handling of the equipment and resulting damage, as well as missing parts, and several other issues I discovered when I came home from work. I would’ve preferred the A team, but it was a Friday...

So they just did it?

Your units are not second rate ...

With multi units you do the whole building load -- and then look at the loads for heat and cooling. See how things relate -- with any unit there is a point that you can't oversize for heat vs AC. Then you go room by room or area by area and lay out the heads. With a multi the goal is not to ever have any head off ... that's how they excel. It's better to have a properly sized multi vs a bunch of single units running away.

The sad thing about HVAC -- most people have average systems and they don't even know what they are missing.

 

[Mesozoic]

So they just did it?

Your units are not second rate ...

With multi units you do the whole building load -- and then look at the loads for heat and cooling. See how things relate -- with any unit there is a point that you can't oversize for heat vs AC. Then you go room by room or area by area and lay out the heads. With a multi the goal is not to ever have any head off ... that's how they excel. It's better to have a properly sized multi vs a bunch of single units running away.

The sad thing about HVAC -- most people have average systems and they don't even know what they are missing.

Yeah, I think the system went in last Friday - due to COVID I'm working from home mainly, but that Friday I had to head into the office to deal with stuff, so I wasn't there to sign off on the work when they finished.

I realize the Daikin parts are not garbage at all, but the installation wasn't done very well - clearly as the system does not function at all . See the Manual J attached.for the calcs.

 

[polizei1]

I would put it right outside the garage, I have mine in the same location. Mr. Cool 24k DIY. Easy to install, and I love it.

 

[HotRod68Camaro]

Figured i'd update this thread. I'm ordering the MrCool DIY system. It's cheaper, and i don't have to pay someone to vacuum/charge the lines. FYI MrCool makes couplers to extend the lines.