window AC Unit in 30'X40' 10' sidewall pole barn is this enough?

[Jwestercamp]

Looking to add a AC unit to my shop. Its a 30' X 40' wood pole building that has typical insulation. The building has a 10' sidewall height. The rafters are open with a 4/12 pitch that is insulated. I am looking at a 240 volt 25000 btu unit. I have to cut a hole in the sidewall, and concerned that this will not be a big enough unit. Any thoughts or insight? thanks!

 

[Bsj04]

Location?

 

[Jwestercamp]

Iowa so it gets pretty humid

 

[theoldwizard1]

1 no.
2 maybe.

A mini-split cost more, but costs a lot less to operate.

 

[Jwestercamp]

won't use it much but when i do i want it to work so maybe save up for a mini-split

 

[Fueler]

I ran a similar AC in the beginning in a similar pole barn. Bigger is always better though.
It will work up to a point but don't expect miracles. There will be "that day" or week that it just can't keep up. Still better than nothing though.

Have a couple of fans to boost the air flow air across and around the shop as the built in fans don't have enough capacity/strength for this kind of application.

I will submit that you probably could improve the situation by installing another one on the opposite wall. But by then the money mounts along with the amps and related expense.
And as is the mantra here....insulate to the max, particularly the ceiling.

Oh, and build your mounting so you can get that unit in and out fairly easily. You will need a support cradle on the outside of the building.
They do need cleaned and serviced to have any chance of survival. They also just **** out. It happens.

 

[theoldwizard1]

won't use it much but when i do i want it to work so maybe save up for a mini-split

30x40 is a large area. For best result you will need 2 air handlers which adds more money.

Haw many hours per year usage determines the pay back. If your average is only a couple of hours per day in summer, the 2 window units are probably best.

The bonus is that mini-split heat pumps can handle heating down to about zero (assuming you buy a model designed for that) pretty efficiently. Not as cheap as wood or natural gas below 30F and probably won't handle the coldest days/night in your neighborhood.

 

[ishiboo]

Window units are cheap. I would plan on two 25K's.

As a general rule, the larger units are more efficient, however given a very similar efficiency, operating two units at the same time is not much less efficient than one unit of 2X the size. The advantage is you can get down to your target temperature quickly. On most days, you could let both run, or if it makes you feel better turn one off.

 

[Deltarat]

I tried one in my 30x50x10 and added another and it is OK,around 80* on a 100* day.I am adding a 4 ton central unit as soon as my guy finds an air handler for it.
I'm in Ms.

 

[Jwestercamp]

i think i am going to try and find a mini-split and go that route. I have a forced air furnace in there and may try and add a 4 ton unit that should take care of everything, but costs $$$. trying to do this on the cheap, however spend the extra money and do it right the first time. I was just hoping to get by with one of these but sounds like a no go. thanks!

 

[rburke65]

Now why would you need to know where this person was located to answer a question about the proper sizing of an air conditioner for their building? I don't understand!.....probaly me though....

 

[sublime68charger]

Now why would you need to know where this person was located to answer a question about the proper sizing of an air conditioner for their building? I don't understand!.....probaly me though....

Different parts of the country have different heat/cool needs.

Florida and Arizona are way different then Iowa or Maine.

Are you talking for 30 hot days a summer broken up over 3 months,

Or a 90 day run of 100 plus?

Rburke I'm thinking your being sarcastic in this by your post count you've been here awhile

No offense with my simple answer.
Sublime

 

[slodat]

I have 30 x 40 x 12 with the 25,000 btu unit Home Depot sells. 1950's construction with insulated walls and ceiling. The unit keeps the temperature at the setting down to 66F on a 100F day. Very happy with it for the $600 cost. I'm adding a big ceiling fan to circulate the air in the shop more.

 

[bullnerd]

Dang! 66! You wearin a jacket in there Slodat?

I had a heat calc done on my new 30x40x10 shop, based on me using the amount of blown in insulation in the ceiling the guy doing the calc recommends, and it came out to 24,000.

You can see my building in my sig if it helps.

 

[slodat]

I crank it down when it's really hot and I'm doing stuff. It's awesome!