Bigger or smaller?

[jbadjones]

Another post about my garage office that I'm building. I will be using a midea inverter window unit to cool the area. I hastily purchased a 12000 btu unit and did research after the fact. The space will be a little under 100 sf. Should I downsize to the 8000 btu unit? Does it really matter?

I'll have a computer going and also some of my guitars and amps and will run the AC at different times during the day via the app while I'm out.

 

[PoorUB]

8,000 is over unless you have a huge heat load.
Think about it. I cool a 900 sqft garage with 18,000. That is 20 BTU per sqft.

 

[jjrbus]

Interesting, Inverter mini splits modulate, ie adjust btu output to conditions. I do not remember exact numbers but my 9000 btu Daikin puts out between 4000 and 11000 btu. I wonder if that is true of the window units and mini splits also? I know with 100% certinty that mine are properly sized but they rarely run at higher speeds and are mostly on the night setting, except during the heat of the day. I know the LG dual inverter window unit in my RV varies output but cannot find any specs to show how much. It ramps up, starts at a low output and increases as needed. That is ideal for the 2200 watt generator!

 

[AntonLargiader]

Wait, 100 SF? 10x10? A one ton unit for that is WAY overkill. It'll never have chance to dry the place out.

EDIT: OK if it modulates low enough then it'll work but BTU/SF is way high. We have 18k for our entire upstairs and it could be 12k.

 

[Jackfre]

A 12k unit is grossly oversized in this space. Given that modulating equipment is only really beginning to gain favor in the US market the bias you have to overcome, or at least understand, is that with modulating gear it is almost more important to look at how low the units output is as opposed to how high the output is. Post after post here shows this because you want to make sure you have “enough.”
We oversized by design and selection. A Manual J gives you a number at Design Condition, the maximum need. We then oversize by selection. The last thing a contractor wants is to get a call on and undersized unit, so…

 

[PoorUB]

I would buy something smaller then the 8,000 if you can find one. I see 5,000 BTU units are available..