Mini Split Questions

Janderso

Janderso

Jeff Anderson
H-M Platinum Supporter
I live in Northern CA.
The insulation is normal.
I want to use this in the garage. It's 20X22 with an 8 foot ceiling.
This is an attached garage.
The BTU calculator says I need 32,000 at 78 degrees and 27,000 at 65 degrees.
Looking for real world experience.
We have hot summers and mild winters. Today it's 57 degrees.
How big a unit do I need?
All I need is to bring the high temp to below 80 and winter temps up to 65.
Thanks for your help.
 
Part of the equation will be whether it will be left on continuously or brought up or down from more extreme ambient temperatures before you will be comfortable in the shop. Guessing 2 tons would probably condition the space relatively quickly, 1 ton would likely do the job but slower. The answer must also take into account how long you want to wait in the house until it is comfortable, or shivering or sweating while working and waiting for it to get comfortable. FYI, one A/C ton is 12K BTU's.
 
Good questions, allow me to think this through out loud.
I can turn on the coffee pot on the way out to my remote control mini-split.
Say 1/2 an hour later on a winter morning I would go out to the garage shop.
In summer, I call ahead, honey, please turn on the mini-split, home in 45 minutes.
No, it will only run when I plan on spending time out there.
Maybe an 18,000 is a good compromise-220v.
These things are awesome and very reasonable.
 
It is difficult for us to be great help with this without knowing a lot more, like attic ventilation, whether walls are in shade or sunshine, etc. It really needs the math to be done taking all into account. The information is online, but you need to take many factors into account, not just square footage and insulation rating.
 
go for the bigger/most BTU's if at all possible.
12,000 is not enough

32,000 would be a better choice, but you are gonna pay higher initial costs,
and you will also give a big monthly gift (power bill) to the same folks who caused you to find new accommodations.

i have a 14,000 btu portable air conditioner, it takes the edge off 100°F days, but i wish i had 20,000 btu's
to make it more comfortable- i have a 3 car garage
 
Ask the pros, they do this stuff every day. Give them the information, or have them come to your shop and make an estimate, cost and capacity. Get multiple bids and recommendations before settling on hardware and contractor. Make sure they understand that it is a workshop, not a house, and the differences that change the equations...
 
In both heating and cooling modes, a heater or air conditioner that barely keeps up on the hottest and coldest days is both the most efficient and the most comfortable. It will not, however, be best at quick heating or cooling.
 
Barely keeps up, is the most efficient? I would think a bigger unit that doesn't need to run constantly to barely keep up would be more efficient.
Keep in mind, I know nothing about it. Just using my flawed common sense with a smile.
 
I installed a mini split last year. It's on all the time, takes care of moisture in the summer and if we're in a heat wave turn it up a little when in the garage. I leave it on 55° all winter unless it get down to ~5°F to below zero i reduce the temp to the minumum 50° and turn on a little electric heater to help. They are very ineffecient once it gets below 20° at least that is what I read. Can't remember the size but my shop is 400sqft.
 
Janderso said:
Barely keeps up, is the most efficient? I would think a bigger unit that doesn't need to run constantly to barely keep up would be more efficient.
Keep in mind, I know nothing about it. Just using my flawed common sense with a smile.
Click to expand...
There are considerable losses every time it cycles. A steady flow at a constant temperature also feels most comfortable and is the most efficient. Designing to meet 100 year record temperatures is not the best plan. A 90% solution often makes the most sense, perhaps even lower in a workshop.
 
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