MRCOOL DIY Mini Split, Seriously, I Think...

[Fueler]

They have to connect to the outside unit. Might as well do the common method, yes?

 

[SynergyMike]

I've got a question regarding the lineset routing. Can you run the lines inside vs. drilling a hole and having them exit the wall where the air handler is?

I'm assuming your asking if the lineset can be routed inside the wall. It sure can and that's how I installed mine. HOWEVER, if you are running the lines inside the wall and then finish the wall, you run the risk of having to rip the wall apart should you need to replace the air handler for some reason (since the lineset is designed as part of the air handler assembly and the lineset does not come off.) With that said, running the lines in the walls is so much cleaner!

 

[3rdgendslmech]

I'm assuming your asking if the lineset can be routed inside the wall. It sure can and that's how I installed mine. HOWEVER, if you are running the lines inside the wall and then finish the wall, you run the risk of having to rip the wall apart should you need to replace the air handler for some reason (since the lineset is designed as part of the air handler assembly and the lineset does not come off.) With that said, running the lines in the walls is so much cleaner!

Sort of, yeah. I should have worded it better. By inside walls I meant exterior of the inside walls. Like you'll see them. I was told and it makes sense in my situation that you should serpentine any excess lineset vs coiling in a vertical position. I'm not going to be heating or cooling 24/7, there's probably going to be a few days between when I turn it on and off. This way I can take up any slack between the condenser and indoor unit and hide it behind a cabinet.

 

[ncboat]

I built a box that sits out from the wall for the unit to mount to. That allowed the line set to run up inside the box to the attic. It is looped in one big loop and drops down through the soffit to the outside unit.

 

[3rdgendslmech]

I built a box that sits out from the wall for the unit to mount to. That allowed the line set to run up inside the box to the attic. It is looped in one big loop and drops down through the soffit to the outside unit.

That's kinda how I was planning on doing mine. Space the mounting bracket out from the wall with a 2x8 or so, run the lines exposed on the interior wall for about 8', then serpentine down 8' to take up some slack then hopefully by the time they pass through the wall and make the connection I wont have a leftover loop.

 

[Browneye]

I've got a question regarding the lineset routing. Can you run the lines inside vs. drilling a hole and having them exit the wall where the air handler is?

You can, I actually did this from an attic space by drilling a hole in the stud-wall header and feeding the lineset down through 'till it got to the fire-block. This latter may well create an issue for you as well.

More importantly, consider not making removal difficult should you need to change out the air handler in the case of repair or replacement. Burying a lineset in a stud wall and then covering over it may well prove the need to undo any construction you did to hide it.

 

[Fueler]

If one has a reason to put the lineset inside the wall or just thinks it's a cool idea I suggest you have someone build a steel shield around them.

Consider that someone, you, the wife, a contractor drills, nails or screws something to that wall......and it happens on a dreadfully hot August day.

 

[3rdgendslmech]

Thanks for the input fellas. I didn't get that far today. I've been fighting a cold and of course on my days off it's hitting me hard. I got the pad poured, fusible disconnect mounted and started running the wiring to the panel, and I mounted the hanging bracket for the air handler.
Just to be clear I'm talking about running the lines exposed on and interior wall, cutting the hole right beside the outside unit. Not in-between the wall cavity.

 

[GRivera]

To add to this incredibly informative thread...

We installed a Mr Cool 36k unit in our 30'x40'x12' shop this spring. Shop is insulated to code for SW Missouri, no windows, two 8' square insulated OH doors, shaded most of the day. The minisplit worked flawlessly all summer keeping the shop cool and dry.

Slipping into winter now and switched over to heat, and about three days in the unit stopped working... fell dead on its face like no power. Tested good voltage all the way back to the inside appliance, and found all three factory terminals for the wiring that connects condenser and evaporator units completely loose, wires just floating. It was easy to find as the unit tried to start up as soon as I pulled the little cover that accesses the wires and touched the harness. Cut power, tightened the lugs, and it fired right up. Has been silently pumping heat into my shop since.

I'm super happy with the unit, and the ease of install, but wanted to share this tidbit with GJ, as I am probably not the only one who has received a unit with un-tightened harness connections from the factory. I didn't think to check these, as I didn't make their connection initially. Something to double check if you have one of these.

Purchased mine from Costco BTW... turned out to be the best bang for my buck at the time.

Thanks for the review. I searched for the 36K at Costco but no luck...how long ago did you buy it?

 

[Slowbra]

Thanks for the review. I searched for the 36K at Costco but no luck...how long ago did you buy it?

Got mine a few months ago! Best investment I’ve made for the garage outside of the lift!

 

[polizei1]

Sort of, yeah. I should have worded it better. By inside walls I meant exterior of the inside walls. Like you'll see them. I was told and it makes sense in my situation that you should serpentine any excess lineset vs coiling in a vertical position. I'm not going to be heating or cooling 24/7, there's probably going to be a few days between when I turn it on and off. This way I can take up any slack between the condenser and indoor unit and hide it behind a cabinet.

That's exactly what I did with mine. I had concerns that bundling it in the corner could lead to trapped oil, so I serpentined mine down the wall. Doesn't look as clean, but I did not want it on the outside of the house, and my interior walls are finished so inside the wall wasn't an option.

I'm also learning that it's easier to just leave the unit on 24/7, and set it to the lowest (62*) when not in use and then bump it up when I want to use it. I also bought a unit off Amazon that measures temperature and humidity to monitor that vs. the unit display. I love it, super quiet and works well in my 3-car garage. I haven't received the first bill yet though so we'll see.

 

[GRivera]

That's exactly what I did with mine. I had concerns that bundling it in the corner could lead to trapped oil, so I serpentined mine down the wall. Doesn't look as clean, but I did not want it on the outside of the house, and my interior walls are finished so inside the wall wasn't an option.

I'm also learning that it's easier to just leave the unit on 24/7, and set it to the lowest (62*) when not in use and then bump it up when I want to use it. I also bought a unit off Amazon that measures temperature and humidity to monitor that vs. the unit display. I love it, super quiet and works well in my 3-car garage. I haven't received the first bill yet though so we'll see.

What size unit and shop?

 

[dcg9381]

If one has a reason to put the lineset inside the wall or just thinks it's a cool idea I suggest you have someone build a steel shield around them.

Isn't that true of PEX or any other electrical work that might be back there running horizontally?

I ran mine "though wall" also. To actually get it to the outside, I put it through a 3" PVC conduit 90 degree sweep.

I should note that my interior walls are "removable" (4x8 sheets) - so it's not a big deal if I need to get in there and I have a ton of depth behind the walls - probably 6-7" before hitting foam insulation.

For residential, I'm debating interior vs exterior also. I can see casing the lines in PVC, but you'll need more depth than standard framing. And if you do it this way, you create a void in the insulation...

 

[polizei1]

What size unit and shop?

24k DIY, 24x32 shop with 12' ceilings above the 2-car and 17' vaulted on the 3rd bay.

 

[ncboat]

Bought my 36k at Lowe's, used veterans discount free shipping to local store, Shop is 36x34 and it did great this summer and now switched to heat. As a side note the line set on the 36k is very heavy and I had a tough time getting a 90 degree bend in the copper section coming out of the unit.

 

[stillnostrebor]

Thanks for the review. I searched for the 36K at Costco but no luck...how long ago did you buy it?

I bought the unit in the spring... May or so.

 

[kjh]

Anyone have experience using the DIY Mr. Cool for heat? I live in an area where it is 15-30F in the winter and I'd like to use the Mr. Cool unit. Unfortunately Mr. Cool doesn't seem to have performance data showing how well it performs at cooler temperatures. They know it will work at reduced capacity down to 5F but can't put numbers behind it.

Any experience is appreciated - I like the DIY nature of the unit but don't want to regret spending $1500 later.

 

[Fueler]

Anyone have experience using the DIY Mr. Cool for heat? I live in an area where it is 15-30F in the winter and I'd like to use the Mr. Cool unit. Unfortunately Mr. Cool doesn't seem to have performance data showing how well it performs at cooler temperatures. They know it will work at reduced capacity down to 5F but can't put numbers behind it.

Any experience is appreciated - I like the DIY nature of the unit but don't want to regret spending $1500 later.

IF it never got below 15 including wind chill you will probably be fine.
Hmm. Guess I don't know what temp you wish to maintain.

If you figure in wind and the times that it actually goes below that then you should consider a backup heat program.
I have a tube heater to backup my mini split. I fiddled with the tube heater thermostat where it would come on when the mini split could not keep up.

The very best advice anyone here will tell you is to over insulate the place.

 

[MattT]

Anyone have experience using the DIY Mr. Cool for heat? I live in an area where it is 15-30F in the winter and I'd like to use the Mr. Cool unit. Unfortunately Mr. Cool doesn't seem to have performance data showing how well it performs at cooler temperatures. They know it will work at reduced capacity down to 5F but can't put numbers behind it.

Any experience is appreciated - I like the DIY nature of the unit but don't want to regret spending $1500 later.

You should be able to find 17*F heating performance at this link.

https://www.ahridirectory.org/NewSearch?programId=41&searchTypeId=3&productTypeId=4

 

[polizei1]

I'm on my first season with it, so far it's been in the low 20's and it's doing just fine. It won't get to the singles until Jan/Feb though so I won't know for sure until then.

 

[juddspaintballs]

I bought the 120v 12k MRCOOL DIY. It arrives on Monday. I'm building out a sunporch as an interior room to my house now, so it's being insulated with proper walls, etc. I plan on using the mini split for heat and cooling, so I'll soon learn how well it does for heat. Worst case, I'll leave the door between the rest of the house and the new laundry/mud room open to let heat into it if the MRCOOL can't keep up.

 

[GRivera]

Today I returned my unopened 24K to Costco and bought a 36k from Ingram’s.

I’ve thought about using wall brackets to install a 36k compressor off the ground but I’m concerned about vibration (pole barn). Is this a legitimate concern?

 

[Fueler]

Today I returned my unopened 24K to Costco and bought a 36k from Ingram’s.

I’ve thought about using wall brackets to install a 36k compressor off the ground but I’m concerned about vibration (pole barn). Is this a legitimate concern?

None whatsoever. they run smoooth.
The 36 is substantially larger and heavier.
I mounted mine off of the horizontal boards.

You will find that the foldout metal brackets they sell are not as stout as the unit itself.
I had to shim up the unit at the outer end of the bracket so the unit was level.
Other than that no biggie.

If I do another one that big I will make my own brackets that would also move it further away from the wall to make it more accessible for cleaning.

 

[akpingel]

North Carolina resident here. I have reached a point where I think I want to give one of these a go. My question is this. I have pitched ceiling in my 30x50 shop that is not insulated nor ventilated. I assume that by running this I will get nowhere near the expected efficiency but can I expect to see a reasonable reduction in overall temps in the summer?

I do want to eventually install a new roof with spray foam but not in the next year at least.

 

[HotrodHR]

Based on the input, advice and suggestions from folks on this thread I purchased and DIY installed the Mr. Cool 18K Btu mini-split. I'm going to attempt to attach some pics and give a brief review...

The install was straight forward. Ran dedicated 240 line and installed the 20 amp circuit myself. I opted for 10/3 cable (ordered it before the unit arrived) and probably should have run 12/2. With the 10/3 (or a 12/3) you end up with an extra wire (we'll call a neutral) that's not needed. Thought I might need heavier gauge in the future, but 10 gauge is a beast to feed up through finished walls and across attic.

Mounting the inside unit was a breeze except working the condenser line up into and through the attic and out the soffit. Plenty of exercise climbing ladders and crawling through the attic. Did this by myself... a helper would make it much easier.

Mounting the outside unit on a wall mount requires two people to lift it in place or use an engine hoist as I did. Drilling into brick was a slow process using a Ryobi battery powered hammer drill. Should have borrowed a larger corded unit from someone. Home Depot charges too much in my opinion to rent so I had an excuse to buy another tool.

Ran the condensate drain behind the sheetrock and out the back wall. I ran the unit for a while before I reinstalled the sheetrock to check for leaks.

Ran the dedicated power and inside unit to condenser line set through the attic and out the soffit. Ordered the brown lineset cover from supplyhouse.com. Adequate product and did the job. I ordered the power cable (from condenser to disconnect) online (electrical whip). Connection was easy with the whip included fittings for the disconnect box and the unit.

The inside unit power and control wires/plug (from the line set to condenser) barely fits through the opening in the cover on the condenser. There's no "fitting" so I used a rubber grommet (sliced one side) to go around the wire and fit in the hole to protect the wire from the sharp edge. Probably overkill. Found the grommet that fit almost perfect at Lowes in a 9 piece kit in the hardware section.

I took my time and did the job over a couple of weekends. The exterior unit runs quiet and the inside unit is unbelievably quiet. My shop is 23 x 23 x 12.5 and the unit cooled it down quickly, and as cold as an icebox.

Overall I'm please with the unit, quality and price. We'll see how it performs when the Alabama summer hits, and how well it does this winter.

Update on Mr. Cool mini-split:

Survived a hot Alabama summer and some cold winter days. Performed excellent both cooling and heating.

Took a couple of attempts to punch in the right settings for heat though. Seems that the unit pauses if you click through heat on and off, louver controls and other settings... just waited a couple of minutes, read the manual and tried again. No problem!

 

[Browneye]

@HotRodHR - yeah...don't confuse the damn thing. LOL

North Carolina resident here. I have reached a point where I think I want to give one of these a go. My question is this. I have pitched ceiling in my 30x50 shop that is not insulated nor ventilated. I assume that by running this I will get nowhere near the expected efficiency but can I expect to see a reasonable reduction in overall temps in the summer?

I do want to eventually install a new roof with spray foam but not in the next year at least.

Since cool air sinks and warm air rises, you would definitely feel cool air - you'll get thermal layers unless you really mix it up.

And while you may not cool the entire shop down, If you put it where it will cool off the area you use the most, you'll enjoy its benefits.

I would throw a 3-ton unit in there and call it good. I think you'll love it. And they don't use much power so it won't cost much to run. I would not try to bring temps from 100 to 70 or even 75 with what you describe. Point it at your work bench or workshop area.

If you could ever install a drop-ceiling and insulate it, then for sure you would have great climate control.

 

[spazzyfry123]

I've got a 20L x 20W x 10H concrete slab garage with the door facing the east, two windows facing the north, and only one wall shared with living space and insulated attic above. It's a typical aluminum door with short windows across.

A few questions:
Is anyone insulating their garage door and/or using different weatherstripping at the door?
12k BTU should cover me, right?
I'm also considering enclosing my rear patio (about 10L x 15W x 10H). Could I get a dual zone to have one central unit that sends separately to the opposite sides of the house with different control? If so, should I bump up to 18k?

 

[Deester]

I ordered a 12k diy mini split from Ingram’s yesterday and found out that you can now get a 16ft line set. It doesn’t come in a package but has to be bought separately at about $206.00. I tried to get them to trade the 25ft for the 16ft but they said they couldn’t do it. They did however, match the Home Depot price which was $100.00 cheaper so I felt okay about the extra money for the shorter line set. I have a 1 story house and the longer line set would have left me with about 9-10ft to coil up. The 16ft one will fit perfectly.

 

[Browneye]

I've got a 20L x 20W x 10H concrete slab garage with the door facing the east, two windows facing the north, and only one wall shared with living space and insulated attic above. It's a typical aluminum door with short windows across.

A few questions:
Is anyone insulating their garage door and/or using different weatherstripping at the door?
12k BTU should cover me, right?
I'm also considering enclosing my rear patio (about 10L x 15W x 10H). Could I get a dual zone to have one central unit that sends separately to the opposite sides of the house with different control? If so, should I bump up to 18k?

If you have a lot of high-temp days then surely insulation will help. Generally those multi-sectional doors are steel-panel. You could always apply styrofoam panels to the inside of the sections.

The DIY units are not multi-zone. If it were me I would install two units. A pro-installed multi-zone unit would cost at least double the DIY units.

And I think you'll find the 12K unit works great for what appears to be a double-garage.

 

[spazzyfry123]

If you have a lot of high-temp days then surely insulation will help. Generally those multi-sectional doors are steel-panel. You could always apply styrofoam panels to the inside of the sections.

The DIY units are not multi-zone. If it were me I would install two units. A pro-installed multi-zone unit would cost at least double the DIY units.

And I think you'll find the 12K unit works great for what appears to be a double-garage.

Yes, it is just a standard, attached two car garage. We're in north Florida, so heat and humidity can get nuts quick - plenty of days in the 90s already this year.

Good info on the multi-zone not being DIY; I'm just now starting my research. If this is the case, I think a 12k for the ~4000 ft³ garage and a separate 9k for the ~1500 ft³ patio will work well.

Thanks!

 

[Deester]

I had to go through 8 inch concrete block and then 1 1/2 inch of stucco! I used the long carbide 1/4 inch drill from HF to line up the holes, then the HF hole saw from both sides!

Harbor Freight...LOL
About the hardest part of my install was drilling through an inch and a half of stucco - it's like concrete. HF had a carbide hole-saw kit for like $30 that had a 3-1/2" cup. Worked perfectly and sawed through that stuff like butter. Great for sheetrock as well - bonus.



I see that y’all are using the hole saw from harbor freight. The only kit I see from harbor freight only has one 3 1/4”. Is there any chance that is the size you used and not 3 1/2” or have they changed the size since y’all bought yours? Would a 3 1/4” even work or will the sleeve only fit 3 1/2”? The only other way is to spend $100.00+ for a core bit or drill a bunch of small holes and chisel out the hole in the brick wall ( a lot of work ) and not nearly as neat.

 

[JasonP82]

Mr Cool posted a new video yesterday on there youtube channel that they now have a MrCool DIY Multi-Zone available for pre-order.

 

[spazzyfry123]

Mr Cool posted a new video yesterday on there youtube channel that they now have a MrCool DIY Multi-Zone available for pre-order.

Nice! Here's the brochure:

https://mrcool.com/wp-content/dox_repo/mc-diy-mz-br-en-01.pdf

 

[Browneye]

Harbor Freight...LOL
About the hardest part of my install was drilling through an inch and a half of stucco - it's like concrete. HF had a carbide hole-saw kit for like $30 that had a 3-1/2" cup. Worked perfectly and sawed through that stuff like butter. Great for sheetrock as well - bonus.



I see that y’all are using the hole saw from harbor freight. The only kit I see from harbor freight only has one 3 1/4”. Is there any chance that is the size you used and not 3 1/2” or have they changed the size since y’all bought yours? Would a 3 1/4” even work or will the sleeve only fit 3 1/2”? The only other way is to spend $100.00+ for a core bit or drill a bunch of small holes and chisel out the hole in the brick wall ( a lot of work ) and not nearly as neat.

The HF kit includes a carbine wrasp file - drill with the big cup then hog it out.

You may not be able to do with that with brick, but worth a shot.

Mr Cool posted a new video yesterday on there youtube channel that they now have a MrCool DIY Multi-Zone available for pre-order.

Oh my...I might need one of those.

 

[thrifty bill]

Just ordered a 12K DIY Mr Cool from Costco. Putting in my 20x22.5 garage. 9 foot eave height. Typical Carolina Carport insulated (kind of) garage. 3 garage doors not insulated plus 2 small windows. Slab is not insulated. Debated getting the 18K unit instead. But I do not need living condition temperatures in there. If I can get 55F heat in the winter and 80F or less AC in the summer, I will be OK. Mountains of NC, so we really don't get that hot in the summer.

Costco price is just so good, and then I get the rebate at the end of the year by using the Costco credit card.

Local HVAC contractor that is doing my house actually recommended I go with Mr Cool DIY on the garage. He quoted me $3500 to install a unit. So $1100 versus $3500. Hmmm.

The 25 foot line set should not be a problem. I'll just mount the inside unit on the rear wall to the left, and the outside unit on the rear wall to the right. Should be able to use up the length at least that is my plan.

Ingrams is almost 20% more for the same unit.

 

[juddspaintballs]

I bought my 12k DIY Mr Cool from Lowes along with the materials to build a small addition on the end of my house. They gave me project pricing on everything and the mini split wound up being around $950.

 

[iced98lx]

Nice! Here's the brochure:

https://mrcool.com/wp-content/dox_repo/mc-diy-mz-br-en-01.pdf

This is going to be very attractive for our lake house remodel! I think we can easily manage with 3 9k heads for bedrooms and an 18k head for the living/kitchen open area. Very attractive.

 

[EricVonHa]

Finally took the plunge. Rebates tough to pass up. Fed is like $300 and local PECO is $200-ish. Home Depot is nice enough to list these right on the product page. SOLD!

Bought an 18k DIY and the install went great. Unit works great. WiFi app-- not good, no connection to the router

I have an old Fios router that is only B & G bands. My guess is that the Mr Cool AP is "N" because the Mr Cool unit never shows up in my Router table of connected devices (yeap, after resetting power to the mini-split and so forth)

My phone connects directly to the mini-split AP no problem (phone direct to the mini-split)

The issue is getting the mini-split to connect to the router.

I can't find any WiFi specs on the Mr Cool WiFi portion. Any techno-geeks know anything?

 

[spazzyfry123]

This is going to be very attractive for our lake house remodel! I think we can easily manage with 3 9k heads for bedrooms and an 18k head for the living/kitchen open area. Very attractive.

That's what I'm sayin'!

Finally took the plunge. Rebates tough to pass up. Fed is like $300 and local PECO is $200-ish. Home Depot is nice enough to list these right on the product page. SOLD!

Bought an 18k DIY and the install went great. Unit works great. WiFi app-- not good, no connection to the router

I have an old Fios router that is only B & G bands. My guess is that the Mr Cool AP is "N" because the Mr Cool unit never shows up in my Router table of connected devices (yeap, after resetting power to the mini-split and so forth)

My phone connects directly to the mini-split AP no problem (phone direct to the mini-split)

The issue is getting the mini-split to connect to the router.

I can't find any WiFi specs on the Mr Cool WiFi portion. Any techno-geeks know anything?

What did everything end up costing after the rebates and the dust settled?

In regards to the WiFi, have you tried one of the WiFi boosters? I put on in my parents' house and it was night and day for the then dead zones. Super cheap and easy to setup.

 

[EricVonHa]

That's what I'm sayin'!



What did everything end up costing after the rebates and the dust settled?

In regards to the WiFi, have you tried one of the WiFi boosters? I put on in my parents' house and it was night and day for the then dead zones. Super cheap and easy to setup.

The router and mini-split are less than 50 ft apart and direct line of site. No signal issues.

The 18k 3rd Gen unit was right at $1,100 after rebates.