Mini-Split AC units

[Edward Bartimmo]

I have been researching options for A/C in the workshop, which seems to be a popular discussion topic on the forum this time of year. It is +100 degrees in Houston and I pulled 10 gallons of water out of air in garage running a dehumidifier for 6 hours. So I thought I would start new thread to discuss mini-split a/c...

It would appear that there are four options for A/C in the garage workshop:

1) standard central A/C Unit on pad outside (including duct work and fan in attic)
2) Window Unit or Wall Unit (huge heartburn with HOA)
3) Mini-split Unit (newer item in market)
4) Mobile Unit (Japanese unit)


I didn't fully grasp the difference between a standard residential a/c unit and the mini-split unit. I now have a better understand of the differences. In rudimentary terms both units have components that needs a pad outside, as well as both units have a seperate component inside the house. This is where the similarities diverge. The mini-split is designed to be a room specific provider of a/c. As such the components and footprint are smaller compared to central a/c. The biggest difference is the complexity of components placed inside the house. In the case of the standard unit it will include ductwork, fan, furnace etc. which are installed in the attic. Whereas, the mini-split unit has no ductwork and the fan unit is affixed to a wall near ceiling within the room to be cooled (think of a smaller version of a/c in hotel room mounted along header of wall).

From what I have read the mini-split surpasses all the other units for cooling power and efficiency, with exception of central a/c. With the room specific design and fewer components the cost of the mini-split is significantly lower than central a/c unit. However, it is about 2-3 times price of a window unit.

Now...has anyone installed one of these units in their shop or house???

Thanks,
Edward

[David Giles]

I installed one in the garage shop several years ago. One of the best tools that I've ever bought. Bought the mini-split off the internet and did the install myself. My AC guy did the final wiring connection and charged the unit for $100. It's been working ever since.

[Eduard Nemirovsky]

Just install it last year in my shop. I bought Mitsubishi Mr.Slim unit. Together with foam insulation of the shop - the best AC unit. I went with this unit because it work as a heat pump, A/C unit and dehumidifier.
This unit was installed by a professional. You can buy Mr.Slim on eBay, but generally Mr.Slim sold only to dealer/installer.
Most important, all ductless split units very sensitive to dust. I am cleaning mine every two month, did not have any problem yet
Ed.

[Van Huskey]

+2 on the mini-splits. Buy on the internet, install it yourself and have an A/C guy do the charge. However, make sure you get quotes and find someone that will do the charge BEFORE you buy since many contractors don't want to do it and either will not or charge stupid prices. I would expect the price to be between $100 and $250 depending on your locale.

[Bill LaPointe]

+2 on the mini-splits. Buy on the internet, install it yourself and have an A/C guy do the charge. However, make sure you get quotes and find someone that will do the charge BEFORE you buy since many contractors don't want to do it and either will not or charge stupid prices. I would expect the price to be between $100 and $250 depending on your locale.

I bought the Mitsubishi unit new on Ebay and installed it myself. A new unit will come precharged and if your good with tools, as most of you are, you will have no problem with the installation. The installation instructions are excellent. Mine has been trouble free and well worth the money.

[Dan Friedrichs]

+1 on the units come precharged. If you can handle tightening the flare nut connection between the two units, you can do the entire thing yourself.

[Brent Smith]

I've been running a Fujitsu multi split in my house since last year. Cooling, heating, dehumidifying and air cleaning mods are great. Two concerns I would have with putting one in the shop would be, as mentioned earlier, dust and one I've realized in the last month or so, odor.

I don't know about the other units mentioned here, but mine collects so much dust it needs cleaning every couple of weeks. It could go longer, but with a noticeable drop in performance in all modes. I'm not sure I would want to put mine in a shop environment for this reason alone.

Odors are another concern. Since a split unit is solely recirculating the air the evaporator coils tend to be a magnet for certain odors, including tobacco smoke, dog odor and some cleaning products. As I learned this summer (my first summer season with it) these odors accumulate quickly and become more than noticeable. In a shop you would probably have to add finishes, solvents and possibly adhesives (CA comes to mind) to the list. Cleaning the evaporator coils can be a bit of a messy job, if you can't take the unit apart.

[Chris Damm]

I had a Daikin mini split system installed in part of my house last year. It is 16000 btu and has a SEER of 16.2. It heats and cools and works great. It was about $2500 installed before Uncle Sam's rebate. It is handling about 1200 square feet in this 90°+ heat we've been having.

[Ray Knight]

Back to an early question, the mini-split consist of wall mounted inside unit, 2-3" hole in wall, tubing and control wiring connected to small outside compressor, power feed goes to the outside unit. Come with coolant pressurized in the compressor, require tubing connections, then sucked down to vacuum with A/C pump, confirm no leak, then release the coolant. Can be done by anybody with basic mechanical skills and access or A/C vacuum pump. I understand that technically legally the final release of coolant requires a licensed A/C technician. I don't have the pump, so it cost me $125 to have that done (you are paying for his time, takes 30-45minutes to suck down, and a bit longer to be sure no leak. For me the advantage of mini-split is no loss of inside floorspace, ease of installation, and cost. I bought an 18,000 btu AC/Heat pump and it has changed my life. My shop is now year round, previous only spring and fall. I cheaped out (environmental greened out) and did not pay for heat coils, so when it gets down into the 20s Fahrheit, the heat pump doesn't work well, and I just close it down and stay in. That is just a few scattered weeks in my area (southern Indiana). We haven't seen an obvious boost in electric bill, but the calculations suggest it should be costing me $15-25 month. Ray Knight

[Jim Becker]

I intend to equip my shop with a mini-split system in the future....

[Joe Wiliams]

I know very little about these and I am interested so a couple questions....

What are the noise levels at each end of the system and is there a limitation of the distance between each unit?

[Chris Damm]

I can only comment on the mini split system. It is much quieter than a window AC. It uses a squirrel cage fan rather than a flat bladed fan.

[Eduard Nemirovsky]

inside unit in ductless mini split is very quiet. Practically, I fill air flow with my hand when I want to check if it's working or not. Outside unit quiet too.

[Tom Rossman]

For anyone interested in the installation process for a mini-split system, there was a segement recently on "Ask This Old House" where they installed one in a garage in Florida.

[alex grams]

Edward,
Did you consider this option which I posted in your other thread? I am also in Houston and in the same situation as you.

http://www.sawmillcreek.org/showthre...73022#poststop