Mini‑split Air Conditioners

[Larry Callahan]

Has anyone put a mini-split heating and air conditioning system in your garage?

My garage is in the worst spot and gets full sun almost all day.

I'm thinking that my next big expense should be a system before car parts. Much of the time it's just too hot in the garage to work.

I LOVE a/c so it will need to be WAY overkill for my 2 car garage. LOL!

177230

[TheBandit]

I just installed two systems on my house. I can walk you through everything if you want. They work great you just need to get a large enough unit for the space.

[John McIntire]

I'm thinking that will be a good investment.

Cooler shop, you'll be able to spend more time out there and get things done.

[Mr Nick]

I intend on getting one in my two car double deep garage. I've read a lot of reviews and done a fair bit of research. Most of them run off 220v, so you may need a pro for that. The install itself, could be a DIY project.

[dhutton]

These DIY Mrcool mini splits come precharged.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1311.R1.TR7.TRC1.A0.H0.Xmrc ool.TRS0&_nkw=mrcool+mini+split&_sacat=0

Don

[Larry Callahan]

Thanks everyone for the input.

How do the pre-charged ones work? Do they use Freon in the evaporator or are they chilling something else outside and circulating it inside?

I hope that makes sense.

[parsonsj]

I installed 3 mini-splits in the garage of my old house over the years, and insulated the garage doors and attic space above it. I had a genuine 72* working environment. Recommended.

However, the inexpensive ones that are pre-charged will almost certainly require annual maintenance, recharging, etc. Do yourself a favor and spend a few hundred dollars more and get a Mitsubishi unit, and have it professionally charged. Then you should have 3-5 years before maintenance is needed. That was my experience at least.

[dhutton]

Thanks everyone for the input.

How do the pre-charged ones work? Do they use Freon in the evaporator or are they chilling something else outside and circulating it inside?

I hope that makes sense.

The lines, condenser, evaporator etc are all precharged.

I don’t have any experience with these units so listen to John...

Don

[StRacerDuke]

Yes, and it works very well. You'll thank yourself if you also add a fan or two for air circulation when you install the mini split. Insulation is key to help keep the operating costs down. I'm in Boston area so the entire garage is R39 with insulated garage doors. It's probably not an issue in CA, but check and see if there is a minimum eco mode you can set it to if you leave it running all the time in the winter like I do.

https://static1.pt-content.com/images/pt/2020/06/P1000850-1.jpg (https://postimg.cc/bdp9Ys6X)

[Larry Callahan]

Yes, and it works very well. You'll thank yourself if you also add a fan or two for air circulation when you install the mini split. Insulation is key to help keep the operating costs down. I'm in Boston area so the entire garage is R39 with insulated garage doors. It's probably not an issue in CA, but check and see if there is a minimum eco mode you can set it to if you leave it running all the time in the winter like I do.

https://static1.pt-content.com/images/pt/2020/06/P1000850-1.jpg (https://postimg.cc/bdp9Ys6X)


Nice garage. Does one evaporator work for you in a garage that size?

[Larry Callahan]

I installed 3 mini-splits in the garage of my old house over the years, and insulated the garage doors and attic space above it. I had a genuine 72* working environment. Recommended.

However, the inexpensive ones that are pre-charged will almost certainly require annual maintenance, recharging, etc. Do yourself a favor and spend a few hundred dollars more and get a Mitsubishi unit, and have it professionally charged. Then you should have 3-5 years before maintenance is needed. That was my experience at least.

I'm comfortable installing and even evacuating it and charging it myself. I just thought that the full DIY kits can't possibly work as well or better than one that needs to be charged.

In in the end I would install it myself but I would call a professional to charge it.

[joeko23]

Larry I have installed these units in my house as well as in my retail store. They are very energy efficient and work excellent for A/C, however they don’t work quite as well for heat IF you live in northern climate where it is regularly below freezing temps in the winter. Other than that they work great and blow really cold air.

As far as installing yourself ALL units come precharged with Freon in the compressor of the outdoor unit (condenser). Things you will need: 220V for condenser outside and 220V for indoor unit, vacuum pump and gauges. You will need to sweat the lines although some newer units come with terminated hoses that are screwed on. Depending how long or short the run is from condenser to indoor unit some Freon adjustment may be needed.

[JustJohn]

I have 3 in my garage as well. 2 down and 1 up in the top storage floor. We insulated the roof with spray foam and so far can't really tell how much electricity it's using because the bill hasn't really changed.

[TheBandit]

Thanks everyone for the input.

How do the pre-charged ones work? Do they use Freon in the evaporator or are they chilling something else outside and circulating it inside?

I hope that makes sense.

As-shipped, the refrigerant is usually located in the outdoor condenser unit. Mr Cool supplies their premade line sets and evaporator already vacuumed down. They use double isolating connectors so that as soon as you connect the lines, the refrigerant is allowed to flow through the system. These are unique to Mr Cool; most units use a standard flare fitting for the lineset, so the system has to be vacuumed down.

There are also manual valves at the condenser unit itself. So basically all you have to do with the Mr Cool units is connect all the lines, manually open the two isolation valves at the condenser, and wire the unit. Some other units do come with the condenser unit precharged, however you have to vacuum the lines and evaporator down before opening the isolation valves to release the refrigerant into the rest of the system.

The Mr Cool units are very cost effective and those are the units I used for my home. I put a 1k BTU unit in my family room which is about 400sq ft and a 2k BTU in my open living space, approx 1000sq ft (livingroom, dining, kitchen open concept). These units are very quiet (both indoor and outdoor) and cool the space quickly. They also have very high SEER ratings, so they will cost less to cool the same space.

In a garage which is likely not insulated and has required vents at the base for exhaust CO, you will want to get a larger unit than the space demands. For a 2car around here I'd probably get an 18kbtu or 24k unit.

[dhutton]

As-shipped, the refrigerant is usually located in the outdoor condenser unit. Mr Cool supplies their premade line sets and evaporator already vacuumed down. They use double isolating connectors so that as soon as you connect the lines, the refrigerant is allowed to flow through the system. These are unique to Mr Cool; most units use a standard flare fitting for the lineset, so the system has to be vacuumed down.

There are also manual valves at the condenser unit itself. So basically all you have to do with the Mr Cool units is connect all the lines, manually open the two isolation valves at the condenser, and wire the unit. Some other units do come with the condenser unit precharged, however you have to vacuum the lines and evaporator down before opening the isolation valves to release the refrigerant into the rest of the system.

The Mr Cool units are very cost effective and those are the units I used for my home. I put a 1k BTU unit in my family room which is about 400sq ft and a 2k BTU in my open living space, approx 1000sq ft (livingroom, dining, kitchen open concept). These units are very quiet (both indoor and outdoor) and cool the space quickly. They also have very high SEER ratings, so they will cost less to cool the same space.

In a garage which is likely not insulated and has required vents at the base for exhaust CO, you will want to get a larger unit than the space demands. For a 2car around here I'd probably get an 18kbtu or 24k unit.

How many years have you run the Mrcool units? Do they lose refrigerant over time?

Thanks,
Don

[joeko23]

The lines should always be vacuumed even if they are preterminated otherwise you are circulating air in the lines along with Freon which isn’t ideal. These are sealed systems and should never leak refrigerant unless there is a problem. My oldest retail store I have them in they are going on 7 years without any problems. The only issue I had was the condensation line didn’t have enough pitch so they started leaking water from the unit once I repositioned the lines all was good.

[TheBandit]

How many years have you run the Mrcool units? Do they lose refrigerant over time?

Unfortunately I've only just installed mine a couple months ago, so I can't say either way. The line sets are sealed with o-rings just like an automotive AC system. The only thing special about them is they have an internal valve that keeps them sealed off until they are connected. It's basically a double isolating quick connector like what you might see used on a hydraulic system.


The lines should always be vacuumed even if they are preterminated otherwise you are circulating air in the lines along with Freon which isn’t ideal. These are sealed systems and should never leak refrigerant unless there is a problem. My oldest retail store I have them in they are going on 7 years without any problems. The only issue I had was the condensation line didn’t have enough pitch so they started leaking water from the unit once I repositioned the lines all was good.

The Mr Cool linesets are vacuumed and sealed from the factory. They have isolation quick connects on all the connections on the outdoor unit, the line sets, and the indoor unit. It's their claim to fame and it seems to have worked fine for my installation.

[CSG]

I believe I am going to try one of these Mr Cool setups. I have a 30x40 shop fully insulated including the doors. Currently I have a 220V window unit. This keeps my shop around 72f for about 5 years and then I have to replace them. I am looking at the 36k Mr Cool unit. It is 16 seer vs 10 on the window unit so hopefully that will help offset some of the cost difference ($800 for the window unit and $2100 for the Mr Cool).

[TheBandit]

CSG just thinking out loud, but have you considered a two zone setup? Their multi-zone 36k unit has a 22.5 SEER and you could use two 18K indoor units spaced apart to help distribute the AC. I don't quite understand why their multi-zone 36k outdoor unit has a better SEER than the single zone; maybe it's a newer design.

[CSG]

After doing more pricing I am actually leaning towards a normal ducted ac system. It is cheaper to buy then the mr cool. The install would be pretty easy and I will just have to get someone to sweat the fittings, vac & charge. I know an ac guy so I am looking to get a price on that piece of the work.