Anyone mount AC condenser inside?

Treetroit City · Feb 15, 2013

Thinking of getting a mini split and wondering if it is okay to install the outside unit inside of a pole barn.

With a proper exhaust fan it seems like it would work. Aren't AC units meant to work when it's hot anyways?

Let's have some opinions.

paddypooh · Feb 15, 2013

AC

AC

I've got a 5000 BTU window AC in the attic and it works great, but in the heat of summer it runs all the time.
The AC unit will make some water in summer as well so plan for the water run off indoors and I think you could pull it off. :biggrin:

That's my penny's worth.
Happy Growing!

Treetroit City · Feb 15, 2013

paddypooh said:
I've got a 5000 BTU window AC in the attic and it works great, but in the heat of summer it runs all the time.
The AC unit will make some water in summer as well so plan for the water run off indoors and I think you could pull it off.
That's my penny's worth.
Happy Growing!

I would hope it would make me some free water. That would be great.

If I used a 5000 cfm 24" fan on a temp controller set for say, 90 degrees would this work?

idoreallytry · Feb 15, 2013

i know a few people who do this as long as its vented somehow it should be ok dont put a fan right by it just get u a turtle vent for ur pole barn roof and a fan pushing air out should suffice,, u just will need a lil air exchange in the summer ur pole barn will be nice and toasty but just ,make sure it doesnt affect (the one posted above seems like it should do the trick) ur grow space and in the summer u might have to add a bigger fan or an intake of fresh air somewhere near it,,,there are more knowledgable guys than me just my two cents,,,we have an hvac guy that pureknowledge myself and poopytebags uses i can ask him good luck mini splits are easy but dont get a cheap one go with the mitsubishis or a good brand,,,peace

bushdoctor215 · Feb 15, 2013

Guys running warehouses in cali run the units inside all the time. Large A/C`s running outside a warehouse all winter long is a dead give away. They make large hoods that go over the top of the unit and exhaust to the roof. A/C is designed to work when it`s hot out. You can get them to work when it`s cold outside but not as efficiently. Plus, stealth is always your friend...

Treetroit City · Apr 5, 2013

Bump to see if I can get anymore thoughts on this.

I have my mini split now so time to make a decision.

Mr Blah · Apr 5, 2013

I think as long as the ambient summer air is not so hot in the barn you'll be fine.
That part of the unit was designed for outside so you'll probably shorten it's life a little, but what the hell, stealth is more important.

Holdin' · Apr 5, 2013

How well this would work would depend on a number of factors. How hot the pole barn normally gets in the summer, how large of an exhaust fan you install, how large of a pole barn, insulation of the pole barn if any, and how large of a unit.

Even if you told me all of those details, it would take a pretty sophisticated calculation to give you a definitive yes or no... But, you are right, condensers are designed to work under high temps. I would say though, be sure to install an exhaust fan at least 400cfm per 12,000 BTU according to the condenser, and it should work just fine without your barn getting 140 degrees. So that exhaust fan you posted would be great. I say go for it.

Adrift · Apr 5, 2013

i would just put it outside and have no worries, unless your trying to hide it from ppl who live by you!

def seems like a big pain in the ass! not saying it cant be done tho...

i know i run my ac all year round, even when its snowing... but i live in decently private settings..

the condenser really is not that loud... and they make kits so you can run them in cold temps..

well good luck!

later

MagniKhan · Apr 5, 2013

I've had a 6000btu window unit blowing into the attic for about two years now. It's right by the ceiling so it draws in air from the room it's in (not from inside the veg box) and exhaust into the attic.
My old flower room A/C is a 14000btu portable that draws warm air from an enclosed room and dumps it into the attic.
In both cases I've had no issues.
As far as a split, I see no reason you could not do it as long as you have plenty of clearance and air flow around the unit. Fresh air intake and exhaust will be a must. I would try to keep the temps under 120f around the unit.

A good way to monitor how well it's doing is to measure the amperage the unit is drawing under normal temperatures and then check it while the temps are about as high as they are going to get. If they are outside of the max amperage shown on the unit then you have problems. If the amperage is borderline ( -1 or 2 amps from max) then you still need to make adjustments.

Treetroit City · Apr 5, 2013

Holdin' said:
How well this would work would depend on a number of factors. How hot the pole barn normally gets in the summer, how large of an exhaust fan you install, how large of a pole barn, insulation of the pole barn if any, and how large of a unit.

Even if you told me all of those details, it would take a pretty sophisticated calculation to give you a definitive yes or no... But, you are right, condensers are designed to work under high temps. I would say though, be sure to install an exhaust fan at least 400cfm per 12,000 BTU according to the condenser, and it should work just fine without your barn getting 140 degrees. So that exhaust fan you posted would be great. I say go for it.

Well the barn is a 24x32. The sealed grow takes up almost half of that so the compressor would be in an area about 24x19. That area comes to approx 500 cf, plus the area above the rafters. I don't know how to figure that footage cause it's the shape of a triangle and it's been a long time since geometry. Lets say it's another 500 cf?

So 1000 cf of heat to exhaust. Seems if I got a 16" 3000 cfm vent fan mounted in the gable there would be no way for it to get too hot.

Oh yeah, the AC is 24,000 btu. Summertime temps can hit the 90's, and the barn in uninsulated except for the sealed grow which has been well insulated.

Treetroit City · Apr 5, 2013

MagniKhan said:
I've had a 6000btu window unit blowing into the attic for about two years now. It's right by the ceiling so it draws in air from the room it's in (not from inside the veg box) and exhaust into the attic.
My old flower room A/C is a 14000btu portable that draws warm air from an enclosed room and dumps it into the attic.
In both cases I've had no issues.
As far as a split, I see no reason you could not do it as long as you have plenty of clearance and air flow around the unit. Fresh air intake and exhaust will be a must. I would try to keep the temps under 120f around the unit.

A good way to monitor how well it's doing is to measure the amperage the unit is drawing under normal temperatures and then check it while the temps are about as high as they are going to get. If they are outside of the max amperage shown on the unit then you have problems. If the amperage is borderline ( -1 or 2 amps from max) then you still need to make adjustments.

Thanks, how does one go about measuring amperage?

Holdin' · Apr 5, 2013

With a volt/multimeter that has an amp probe. You can pick up a fairly cheap one at home depot or Lowes.

Holdin' · Apr 5, 2013

Third Coast said:
Well the barn is a 24x32. The sealed grow takes up almost half of that so the compressor would be in an area about 24x19. That area comes to approx 500 cf, plus the area above the rafters. I don't know how to figure that footage cause it's the shape of a triangle and it's been a long time since geometry. Lets say it's another 500 cf?

So 1000 cf of heat to exhaust. Seems if I got a 16" 3000 cfm vent fan mounted in the gable there would be no way for it to get too hot.

Oh yeah, the AC is 24,000 btu. Summertime temps can hit the 90's, and the barn in uninsulated except for the sealed grow which has been well insulated.

Hmm... how many lights do you plan on running, and what is the exact square footage and ceiling height of the sealed grow space? And is this a completely new setup?

You've at least got the right idea with the 3000 cfm exhaust, I'm just a bit concerned about temps of your sealed grow during max load in the summer. The part of the barn with the condenser will surely be warm, which will add a load to your grow space. How is the sealed grow space be sectioned off from the rest of the barn, and with the grow space be insulated?

I wish I'd gone to engineering school so I could tell you exactly what you'd be facing. But, I can give you a pretty good idea though with the additional info. It won't be a complete shot in the dark but, may require additional cooling... that's pretty much how I'm feeling about it at present time. You have to remember you'll be cooling your sealed grow space as if it weren't running HIDs, plus 3500-4000 BTU per 1kw.

Edit: air cooled hoods???

MagniKhan · Apr 5, 2013

Third Coast said:
Thanks, how does one go about measuring amperage?

To the A/C you will most likely have two 220v wires, a neutral and a ground ( some just have the ground ).

http://www.myflukestore.com/p12880/fe_324.php

Using a clamp (or hook type like Klines new probe)type take one of the 220 wires and place the clamp around the wire. The usual nomenclature is "leg". So measure one leg, then the other.

In these pictures I'm checking the amperage on the air handler..

...the top one shows .9 amps and the lower one shows .7 amps, so the reading would be .9 amps. ( you do not add the readings)

I'm reading the air handler so the readings are different cause it taps one leg to run 120v components and then the 120v blower on the other leg.
The compressor should be about the same from one leg to the other as that is most likely a 220v motor.
Remember with alternating current 120v has a neutral and a hot, 220v both are hot and a "neutral" is not needed as the current is alternating so both cycle between hot and neutral ( 60 cycles a second). If there is a slight difference in the reading it's not a problem, some components maybe on one leg that accounts for the difference.

By the way a cheap clamp type meter will do , you don't need a fluke like in the link, it's just an example.

Treetroit City · Apr 5, 2013

Holdin' said:
Hmm... how many lights do you plan on running, and what is the exact square footage and ceiling height of the sealed grow space? And is this a completely new setup?

4K Gavita so no air cooling for flower. 2x600 plus 432 watt T5 for veg.

flower=12x13x8.5 veg=8x13x8.5 brand new setup.

You've at least got the right idea with the 3000 cfm exhaust, I'm just a bit concerned about temps of your sealed grow during max load in the summer. The part of the barn with the condenser will surely be warm, which will add a load to your grow space. How is the sealed grow space be sectioned off from the rest of the barn, and with the grow space be insulated?

7/16" osb sandwiching R-13 insulation. For a better look see here.
https://www.icmag.com/ic/showthread.php?t=254875

I wish I'd gone to engineering school so I could tell you exactly what you'd be facing. But, I can give you a pretty good idea though with the additional info. It won't be a complete shot in the dark but, may require additional cooling... that's pretty much how I'm feeling about it at present time. You have to remember you'll be cooling your sealed grow space as if it weren't running HIDs, plus 3500-4000 BTU per 1kw.

I figured 4000 btu per 1K as well so I should be all set in that regard.

Edit: air cooled hoods???

MagniKhan said:
To the A/C you will most likely have two 220v wires, a neutral and a ground ( some just have the ground ).

http://www.myflukestore.com/p12880/fe_324.php

Using a clamp (or hook type like Klines new probe)type take one of the 220 wires and place the clamp around the wire. The usual nomenclature is "leg". So measure one leg, then the other.

In these pictures I'm checking the amperage on the air handler..
View Image

View Image

...the top one shows .9 amps and the lower one shows .7 amps, so the reading would be .9 amps. ( you do not add the readings)

I'm reading the air handler so the readings are different cause it taps one leg to run 120v components and then the 120v blower on the other leg.
The compressor should be about the same from one leg to the other as that is most likely a 220v motor.
Remember with alternating current 120v has a neutral and a hot, 220v both are hot and a "neutral" is not needed as the current is alternating so both cycle between hot and neutral ( 60 cycles a second). If there is a slight difference in the reading it's not a problem, some components maybe on one leg that accounts for the difference.

By the way a cheap clamp type meter will do , you don't need a fluke like in the link, it's just an example.

Thanks for taking the time to explain. Seems easy enough. :tiphat:

MagniKhan · Apr 5, 2013

Holdin' said:
Hmm... how many lights do you plan on running, and what is the exact square footage and ceiling height of the sealed grow space? And is this a completely new setup?

.....

He has a thread here that shows detailed pictures of his build, it's been coming along well.

Third Coast said:
Well the barn is a 24x32. The sealed grow takes up almost half of that so the compressor would be in an area about 24x19. That area comes to approx 500 cf, plus the area above the rafters. I don't know how to figure that footage cause it's the shape of a triangle and it's been a long time since geometry. Lets say it's another 500 cf?

So 1000 cf of heat to exhaust. Seems if I got a 16" 3000 cfm vent fan mounted in the gable there would be no way for it to get too hot.

Oh yeah, the AC is 24,000 btu. Summertime temps can hit the 90's, and the barn in uninsulated except for the sealed grow which has been well insulated.

It sound like it may work. Thats not a bad size area and with some air flow it's just crazy enough to work. :good:

Keep an eye on temps amp load and smell, and you'll be good, if you're getting above 125f in that space I would make adjustments.

Holdin' maybe able to tell you the operating temperature range on those units in general. The manual for the A/C may also have some useful info on operating temperature range, though it maybe a little conservative.

growingcrazy · Apr 6, 2013

I think the most important question hasn't been asked yet.

Is the pole barn in direct sun all day or is it in a shaded location? I think you will be ok temperature wise in the the summer, its just a question of whether your 95-100 or 115-120. That is a large difference depending on the building's sun exposure.

What do you have planned for intake when the exhaust is running? Or is the pole barn drafty enough as is?

Big_Al's_Buds · Aug 16, 2017

Did you ever do this? Thinking to do the same sort of idea, just in winter to heat my house

Treetroit City · Aug 17, 2017

Big_Al's_Buds said:
Did you ever do this? Thinking to do the same sort of idea, just in winter to heat my house

Wow, blast from the past seeing this thread.

Yes I did and it has been there ever since. One of the reasons for this was because I had no water run to the barn so come late fall I store over a thousand gallons to get me thru winter. The heat from the unit keeps the water from freezing. Works like a charm but yeah it gets hot in the summer. Over 100 during the day up to 115. Not the most efficient I know but it has worked.

Anyone mount AC condenser inside?

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