Mini Split in Garage DIY - Bad Idea?

[tdott]

With the Florida heat quickly approaching I have thoughts of adding a mini split to my 400 sq-ft garage.

My plan is to install/mount everything myself and have a HVAC buddy pressure test/evac/fill the system.

I came across this ECOX brand which seems to be popular in Latin America.
So how bad do you think one of these systems are? Everyone always mentions all the top brands that are 3x-4x as much, my needs / expectations are not much. Mainly will probably only use it to cool my garage a handful of times a month during the summer months here in FL just to make it more comfortable to be out there, not expecting sub-zero temps.

I'm planning to get the following unit:
12000 BTU - 1.0 ton - 110V - 16.5 Seer Inverter - Wi Fi - 400 SQ FT - $ 425.00


Complete garbage or okay for light use?
My main aim is just for it to be better than a portable unit which I prefer not to have to resort to.

 

[Mamrak76]

Here is my 2 cents. What kind of insulation do you have? Even if you have a properly sized unit, it will struggle to keep up with the load due to your insulation. If you have a proper r value for your walls and ceiling then I have seen hard foarm insulation sheets cut and used to insulate the door. My garage has a large 10000 btu (almost a ton) window unit and it works alright but it's not perfect. I need to insulate my garage door and roof and It would be like inside my house. So yes I think it would (not having that particular brand experience) still work.

 

[tdott]

Thanks, I forgot to mention, my attached garage is finished, ceilings are finished, I do not know the R-value, I assume the walls are insulated, not sure about the ceiling above since I haven't been in the attic, there is no floors above the garage. I was planning to add insulation to the doors and perhaps even the attic.

I think it would work for my needs.

 

[HoosierBuddy]

My plan is to install/mount everything myself and have a HVAC buddy pressure test/evac/fill the system.
.

Ask that dude what he thinks about the unit.

Phil

 

[turbowoodworker]

I'm not sure when "You get what you pay for" should be brought up. I'm not an expert but $425 vs $2000 and up? It is hard to believe that there is no difference between the two price points. Quality, materials, warranty, etc.
Just my humble statement.

 

[rebelranger]

Please do it and let us all know. No one will know until it's tried. Think about caveman and meat, it was always eaten raw until someone tried it cooked... changed the way people lived. Maybe this mini split will change garage hvac

 

[OzarkMan]

I have a 12,000btu mini split purchased off Ebay two years ago for $550. I have the one with the ceiling cassette instead of the wall hanging air handler. It has been in service for the last two years running silently in the background. So far, so good. It is a Senville brand with a Toshiba compressor that does heat and cooling. Both work excellently in my new office addition. So yes, You don't need to spend 2,000 on a system.

 

[turbowoodworker]

Yah but it never gets very hot in Mesa

 

[softailtom]

Pioneer mini split, got a 18k unit in my shop 6 months working good so far.http://www.highseer.com they are in south florida and was happy with the customer service.

 

[Jinks]

I had a 12000 BTU unit installed in about 450 sq ft of garage/shop about three years ago. I wanted the warranty, & MrCoolDIY wasn't available so I had a local "professional" install it. They had to use my tools, & I would have done a better job, but it works. Way too expensive, but it works. If it ever dies I'll replace it with a MrCoolDiy at half (or less) the price & do it myself. If the one you're looking at fits your budget give it a try. Just be aware that once you have it you'll use it! I thought the same way as you while I was shopping, but after it was in I really started using it! I've used it twice this week & will probably use it the rest of the summer. Once you realize you don't have to sweat while crawling under a car why the hell would you leave the A/C off?...... Run the hell out of it!!!..........

 

[justinjoyal]

12kbtu for 400 sq ft is plenty if well insulated, if not, you might wanna step up to 15 or 18kbtu, depending on R-values.

 

[Fixin'Stuff]

12kbtu for 400 sq ft is plenty if well insulated, if not, you might wanna step up to 15 or 18kbtu, depending on R-values.

Does the variable capacity of inverter systems affect this? It seems that having 18K BTU would be great for quick cool down, then the system would automagically throttle back to a much lower output to maintain temp. In theory at least, it seems that an inverter system makes it harder to oversize, at least within reason.

I'm close to pulling the trigger for a system to cool a 475 sq. foot garage in the hot and humid Houston area. The walls are R13, the ceiling will be R-30-ish, but the double door is only R7. I'm considering going with 18K BTU just to have some margin on those really hot and muggy days of summer. What I'm uncertain of is just how far these can ramp down. Does it drop to 9K BTU? 6K BTU? Less? I'm uncertain where to find an actual number.

Around these parts, keeping the air dry is at least as important as keeping it cool. A cool, clammy space isn't very comfy. We already experience that to some extent in the house when the outside temp is "only" around 80. The all-or-nothing split systems cool the air too quickly on those days to do a good job of dehumidifying.

 

[Jinks]

No numbers, just some experience. My shop in Florida is a single care garage added to the end of the house & a guest bedroom opened into it to serve as a shop area. Total sq. footage is just over 450. The southern wall (the long one) & the eastern wall (short) are uninsulated. The west end is a 7 X 10 insulated garage door. The rest is shop/house that is insulated. It's also under a second floor that is insulated & air conditioned.

My 12K mini-split takes a few minutes (30/45) to cool to a comfortable level if I let the space heat up. If I start it early in the morning when I know I'll be working out there it's cool almost from the start. I know that once it gets to the set temp the inverter slows things down, but I never notice any real change in the air flow from the air handler. Both units are scary quiet, but the compressor becomes almost silent when it slows down.

I've had mine about three years. Never any cool clammy feelings, no big change in the electric bill, & in the evenings I can open the garage door, shut the a/c down, & sit in the shop to watch the sunset while staying cool & dry for at least an hour.

While researching mine I had every sales geek/a/c "professional" try to sell me 24K. My online research just couldn't justify that. I thought I'd only use it lightly, but it turns out I use it quite a bit during the summer. I haven't been disappointed in 12K & probably would be just as happy with 18K, but that would be the largest the shop could handle.

 

[dsimatt]

Does the variable capacity of inverter systems affect this? It seems that having 18K BTU would be great for quick cool down, then the system would automagically throttle back to a much lower output to maintain temp. In theory at least, it seems that an inverter system makes it harder to oversize, at least within reason.

I'm close to pulling the trigger for a system to cool a 475 sq. foot garage in the hot and humid Houston area. The walls are R13, the ceiling will be R-30-ish, but the double door is only R7. I'm considering going with 18K BTU just to have some margin on those really hot and muggy days of summer. What I'm uncertain of is just how far these can ramp down. Does it drop to 9K BTU? 6K BTU? Less? I'm uncertain where to find an actual number.

Around these parts, keeping the air dry is at least as important as keeping it cool. A cool, clammy space isn't very comfy. We already experience that to some extent in the house when the outside temp is "only" around 80. The all-or-nothing split systems cool the air too quickly on those days to do a good job of dehumidifying.

I just installed a 18k unit to handle most of my 1200sgft house after they did a load calculation and I could have gone to a 24k unit but was told it mostly would have been wasting money. I only used the ac once when it was a little to warm in here and while it put out nice cold air, the outside fan was barely turning so it only did what was needed.


I did talk a lot with the guy about oversizing and he said that's the nice thing that within reason you can't oversize as it will only put out what the load dictates, that said putting a 30k unit in my house wouldn't work well.

The correct thing is to get a load calculation done but where you are will take a lot more to cool the same area as where I am so I wouldn't be to concerned on oversizing it, also they have dehumidify mode to get the moisture out to.

 

[Marctrees]

What ever happened to old school through wall (window) AC's ?

Mini split advantage over that for a 400 ft2 open single room?

In FL, no heat function needed.

Like $400 - 500 for unit for that application - Quick cool down, not to oversize.

We have 600 ft2 one open room shop, and two 14kbtu units at two opposite ends.

Both cool it down quick, then usually just run one.

About $350 each.

One goes bad and not easy fix?

Buck up and buy a replacement.

Try getting your minisplit fixed for $350.

On top of all, with our 2 units we have redundancy if one should go down.

Works great for us in S TX.

Marc

 

[wendlwacker]

I have a mr cool brand 18000 did it all myself. Had some minor issues but so far so good. I did purchase it from a local supplier so that helped.

 

[yeldogt]

A spray foam building can go to 1000sf per ton in my area (Mid-Atlantic) -- that's factoring the unit running ... not bringing down a 100 degree room to 70 in 1/2 hour. 12k for 500sf will cool almost anyplace

Some VS units go can reduce more than other -- they achieve max efficiency around 80%.

Some of the cheaper units on line -- don't come with all the parts (install kit).

 

[tdott]

Ask that dude what he thinks about the unit.

Phil

He says he has 0 zero experience or direct feedback, he works mostly with industrial units probably the size of my garage.

 

[tdott]

What ever happened to old school through wall (window) AC's ?

My garage has no windows. Prefer not to punch a giant hole in the wall.
The mini split system only requires a small hole, 2-3" I believe, nothing near as big as a wall unit. Mini splits I believe are much more efficient also, and would be quieter and cleaner install with wall unit up high and the condenser/fan being completely outside, not that sound matters to me but those could be reasons why others may go for a mini split over a window unit.

 

[theoldwizard1]

What ever happened to old school through wall (window) AC's ?

Mini-split (heat pump or A/C only) are typically MUCH more efficient than a window shaker !

 

[theoldwizard1]

OP - If the garage has NO INSULATION in the attic, I think you are fighting a losing battle ! You need at least 12" of fiberglass to keep that 100++F heat from penetrating. A powered exhaust fan with a proper inlet would help a lot also.

 

[tdott]

OP - If the garage has NO INSULATION in the attic, I think you are fighting a losing battle ! You need at least 12" of fiberglass to keep that 100++F heat from penetrating. A powered exhaust fan with a proper inlet would help a lot also.

I finally crawled my lazy *** up there and there is no insulation over the garage only over the room next to the garage.

What type of insulation should I go with? Same as they have over the other room?

https://goo.gl/photos/51gYypQ5pNme7SFy9

https://goo.gl/photos/ea6SdZy5Jk5674Nd7

 

[Falcon67]

Yah but it never gets very hot in Mesa

Not today...but Tuesday, look out

 

[eddieK]

Here is my 2 cents. What kind of insulation do you have? Even if you have a properly sized unit, it will struggle to keep up with the load due to your insulation. If you have a proper r value for your walls and ceiling then I have seen hard foarm insulation sheets cut and used to insulate the door. My garage has a large 10000 btu (almost a ton) window unit and it works alright but it's not perfect. I need to insulate my garage door and roof and It would be like inside my house. So yes I think it would (not having that particular brand experience) still work.

At that cost...really what do you have to lose? It should help greatly with the humidity.

If there is any part that is crucial, keep the drain line low (below the refrigerant lines as it passes thru the wall). Anything you can do to limit the heat gain does help.

 

[Falcon67]

>Try getting your minisplit fixed for $350.

Last time I had a service call to replace a start cap, the bill was $250 so what's your point. If it blows up, he can thrown that one over the fence and get a new one for about what it'd cost to service/repair.

>At that cost...really what do you have to lose?
Winner

Insulation - ANYTHING. R19~R30 batt bundles are fairly cheap, or rent a blower and a few bags - done.