Garage Minisplit A/C

[ssanto]

Dang it's hot here in Texas. My thermometer in my garage is reading 96... I can work for about 5 minutes before I'm starting to get drenched in sweat.

Looking at the Senville mini split systems. Seems pretty straighforward and I don't mind getting the vacuum pump and whatever other tools I'd need to install it. It comes pre-charged but I'll need to add Freon to account for the longer 50 ft. lines I'll need. I do most of my own A/C repair work anyway so I don't mind adding to my toolbox.

It's a 700 square foot 3-car garage with un-insulated wood doors. Right on the other side of those doors is full sun and 110 degrees.

Here are the two units I'm thinking about:
* 24000 BTU A/C and Heat Pump, 18 SEER, 1000-1250 sq ft - $1350
* 18000 BTU A/C and Heat Pump, 22 SEER, 750-1100 sq ft - $1650

I'm leaning towards the bigger 24k BTU unit with the lower SEER efficiency rating. At most I'll be running the A/C for maybe 20 hours a week while I'm in there working on my car. And then won't need it much in the cooler months. I played with some cost calculators and since I'm not using it for primary house cooling, the poorer 18 SEER won't make much difference in the long run. Instead, I'd be getting a bigger BTU unit which I feel like I'd need since half the garage is un-insulated doors. I figure it'll cool off quicker and keep up better. And it's cheaper!

I read other threads about sizing, but dang I'd rather be safe than sorry given my climate.

My only concern that the 18 SEER one is the "old crappy model" that is not good for other reasons.

Thoughts?


Thanks,
Sal

 

[ssanto]

Also just saw this in the installation manual:



So with my 50' line run, then it looks like I'd need the 24k anyway. Hrmmm...

 

[PoorUB]

Also just saw this in the installation manual:



So with my 50' line run, then it looks like I'd need the 24k anyway. Hrmmm...

Look again, that is 50 meters, 164 feet.

 

[jjrbus]

The tool nobody wants to buy!

https://trutechtools.com/Pro-Set-FT...AOXYKmMEfR34mbQazpn2FqlLETYB3JUsxH3cl7KRismcg

 

[pcmeiners]

A gauge is not needed. Place the copper tube in the flaring die about 1/32 sticking past the dies flat surface, possibly a particular die will need more exposed tubing, possibly a 1/16".

 

[fitter30]

Larger unit will cool building off quicker but will not pull the humidity out as fast. Most of the heat is easy to get out tools ,cars and anything metal. Anything that might hold moisture is harder. If your not getting into the garage only once or twice a week i want to cool right now. But the humidity will not be removed.

 

[ssanto]

I don't have much hope that I'll be able to control the humidity. The garage door opens and shuts maybe 5 times a day. But for that 8 hours on a Saturday when it's 110 outside, I need to get it frosty in there (and I'll lock the door to prevent the fam from opening it! hah!)

 

[toyotadriver]

Since you won’t be running it all the time, I’d go with the 24k. You’ll appreciate the extra capacity. Plus, it should be an inverter so it should be able to ramp down a bit as it cools off inside. If you were going to maintain a steady temp, I’d recommend the 18k

 

[dcg9381]

Larger unit will cool building off quicker but will not pull the humidity out as fast. Most of the heat is easy to get out tools ,cars and anything metal. Anything that might hold moisture is harder. If your not getting into the garage only once or twice a week i want to cool right now. But the humidity will not be removed.

It's 100-102 this week. Cooler than most weeks.
Many of these units have a "dehumidify" mode. But I can tell you that our 24k pours a steady stream of water out in central Texas. My space is a little bigger per BTU, but our insulation is perhaps better in the space.

I have a 17 SEER Daikin 24k. I'd buy another one tomorrow.

 

[ssanto]

Got the installation completed today and wanted to post an update. It's 76 in the garage today and it blows 52 on cool and 104 on heat.

The outside unit needed to go clear across the other side of the house from the garage so I needed to buy two additional line sets to get it to reach that far. Still well within the line length limits for the 24k unit.

All in all I probably have 16 hours into the job... spread out over a week. Which I suppose isn't so bad since I had that long run to deal with for both the lines as well as the 220. Lots of conduit for the 220 to get up and around. And then I have a complicated run of PVC pipe to get the condensation drain out of the garage. Also needed to add 1.5 lbs of refrigerant to account for the longer lines.

Unit was $1300 and I probably have another $800 in line sets and other materials. And maybe $200 in tools. So that ain't bad! I'd bet this would have been $5k+ to have an HVAC company do it given my complex install .

Thanks!

 

[ssanto]

The only dumb thing about the install was that with 50' + 25' the line was going to be about 3' short assuming I could route the cable as efficiently as my measuring string. So I had to add the third set of 16' and now I have more than enough but up in the attic it looks kinda dumb with a big whoop-de-whoop in the line to take up all the slack. Oh well.

 

[My Old Tools]

I put a 36k MrCool in my shop, 30x40x12 with a 6/12 pitch. It is overkill, probably could have done it with a 24k. The first two days it ran it pulled a ton of moisture out of the shop. I keep my shop closed up and it is fairly tight, so even though i don't keep the
AC running all the time, when I do crank it up, there doesn't seem to be as much moisture as there was that first time.

 

[rockcrawler]

I put a 36k MrCool in my shop, 30x40x12 with a 6/12 pitch. It is overkill, probably could have done it with a 24k. The first two days it ran it pulled a ton of moisture out of the shop. I keep my shop closed up and it is fairly tight, so even though i don't keep the
AC running all the time, when I do crank it up, there doesn't seem to be as much moisture as there was that first time.

I have a 35x45x14, peaks at about 20’, and have been seriously considering two 24K mini split systems. Glad to hear you are having success with the 36K.

 

[My Old Tools]

I peak at 22', open to the rafters, with 12" of insulation on the ceiling. My unit sits at 9'. I let the building stratify, so the loft stays pretty hot.