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100 sq ft and mini split?

PoorOwner

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I am planning to use a 12k mini split in a 100 sq feet interior. it is an outside shed with R15 roxul walls and ceiling, 2x 36" x 36" window. The floor doesn't have any insulation, it is plywood and it sits on skids.

It doesn't get too hot inside when it's hot (90s) outside. But once I go in there and close the door I feel my body heat up the place and feel stuffy, and gets hot and sweaty. it's uncomfortable for more 10 minutes. It's like sitting inside a car turned off with everything closed up.

The windows are not as big as it sounds, as they only open 14" horizontal and there isn't any option for a window unit.

The mini split I have actual cooling range is 4000-11000 BTU.
So my question is, yes this is oversized, I looked into a 9K unit, but unless going with nice mitsu or fujitsu, the cheaper 9K only go as low about 3750 BTU so it is not worth to buy the slightly smaller 9K unit.

The 12K AC unit I already have, so only investment is to put a hole and just try it out. If I use my laptop or play music there is definitely some heat that needs to be extracted out.

Do you think it will work or will it short cycle too much? humidity isn't too big a concern in my climate. I have not actually experienced with mini split short cycling, but I have read it can happen.

It seems though, if I were to work there for hours or take an extended nap, I should open the window a little because there isn't any fresh air and the place seem a bit too air tight.
 
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Gravedigger

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It will definitely short cycle too much but with no humidity it might work . A 9K unit is way over sized also but that is the smallest mini split available.
 

Infinia

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nope AC is way overkill unless yer in the desert, but from your usage description check your cross ventilation and perhaps a ceiling fan.
 

soob

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It'll short cycle but if you're like me you can just set the temperature really low and let her rip.
 
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PoorOwner

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I don't know if this is how it works, but I monitored the temperature inside (I was not inside). Today it is a cool day max of 78F outside, It raised from 61F to 75F by late afternoon. Seems like that is a heat load of 355 BTU / hr (raising 2 degree per hour).

So it is shoulder season for sure, in certain cooler months everyone's AC becomes oversized and needs to cycle off for the cool days if AC needs to run.


On a day that goes as hot as 100F outside, it would start at 75 in the morning where I would need power to cool it to 65.. plus the heat gain. I do not know how to calculate the BTU needed, but I would think something ultra low like 2500 BTU would not do the job, and 4000 BTU might be OK.
 
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PoorOwner

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The job can be done w a $130 5kbtu window ac unit from Wally or any big box.

I just don't understand this minisplit bandwagon.

Now for a 10x10 shed.

Wow. Marc

No, the window doesn't open wide enough for a window unit.
I already have the equipment.
 
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