# Air conditioning question



## Skool (Apr 6, 2012)

Hello, I've been reading some about indoor grow rooms. I have a plan, somewhat, to build my own room. I have enough 2x4's to build a 4'x4' room that will be 8' tall. I would like to use two 600 watt HPS lamps in there with glass covered vented hoods or cool tubes. From there I need a little help in my thinking. My thinking says to cool those vented hoods pulling the air from outside the room and with the air also exiting outside the room. What I am having a problem with is understaning how I air condition the room. Do I seal the room off totally and use a mini split to keep it cool? How do I get fresh air into the room? If I pull air into the room and then pull the air out of the room how to I keep the room cool if I am pulling the cool air out?


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## bwanabud (Apr 6, 2012)

Well, depending on average room temp...the vented lites only raise your temp 5%, so you may not need cooling  An exhaust fan is needed for fresh air anyway, so pull that air thru a passive vent from the house.

a 4x4 room will only need a 5k btu room unit...if needed.


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## Skool (Apr 6, 2012)

bwanabud said:
			
		

> , so pull that air thru a passive vent from the house.
> .


 
That is where I am confused. I want good air movement inside the grow room. The thing is, is, that I air condition the house. If I pull air through a passive air intake into the grow room (room inside a room really) do I have to push that air outside of the house or can I just dump it into another room so that I am not pushing ac cooled air outside. I am trying to not overwork my house central air system. Did that make sense?


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## bwanabud (Apr 6, 2012)

Yes, pull the air into the grow room...then dump it outside. Unless you want your house smelling like a big sweaty stinky bud


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## orangesunshine (Apr 6, 2012)

dumping the air into another room will likely be less stressful on your household a/c---you might consider running your lights sat night---you might also choose a room farthest away from the thermostat to dump the grow air in---a carbon filter if you don't want your whole house to reek like herb 24/7---lots of variables---not sure if we have an hvac specialist in the house


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## bwanabud (Apr 6, 2012)

I'm an HVAC engineer, just figured his grow room was in the basement.

Running the lites at night will help, but still need fresh air for the plants.


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## pcduck (Apr 6, 2012)

:confused2: I have not a clue what they are asking.



> how to I keep the room cool if I am pulling the cool air out?



This is what is confusing me:confused2: What cool air?

I run two 600 watt a/c reflectors in a 4x4 space.
I start with my carbon filter> wye duct> through both a/c reflectors>wye duct> fan > duct work to the window and outside when warm out side, if cold I run the duct work into my bedroom for added heat. I have a passive intake for cold nights and on warm days I draw air from outside the window. My tent allows me to close off passive intake when warm and then I can use the fan intake directly from outdoors. 

I do not know if that helps but that is what I do.


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## Growdude (Apr 6, 2012)

pcduck said:
			
		

> :confused2: I have not a clue what they are asking.
> 
> 
> 
> This is what is confusing me:confused2: What cool air?


 
He is concerned that the draw from his tent is going to exhaust his AC in the house.


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## PuffinNugs (Apr 6, 2012)

not only will it exhaust the cold air out if venting to outdoor, if enough negative pressure in the house it will pull in hot outside air from leaks/cracks in the house itself 

a mini split is the best idea, that way its not creating more negative pressure and is intaking air from outside, your inline fans for the lights though may still cause the above problem though.


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## pcduck (Apr 7, 2012)

Growdude said:
			
		

> He is concerned that the draw from his tent is going to exhaust his AC in the house.




Oh ok, thanks

In that I case I would run separate duct work. One duct work from window to lights, fan then back to window. 2nd duct work from carbon filter  to a fan and exhaust to a room inside the house. That way there is no negative pressure inside the house and you are not depleting your ac air to the outside of the house.


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## Skool (Apr 8, 2012)

pcduck said:
			
		

> :confused2:
> 
> 
> 
> :confused2: What cool air?


 
Oh, I am talking about the cool air already in the house. I am going to cool the lamps with outside air and I want to cool the grow space with air from inside. It is the inside air that I have already cooled (via central air) and that I would like to cool the grow space with the grow space with that I would like to avoid pumping to the outside. I fear it will cause my light bill to grow more than I need it to. It is already going to take a small hit with two 600 watt lamps, two fans for pulling air, and a fan inside the grow space to blow on the plants. 



			
				orangesunshine said:
			
		

> you might also choose a room farthest away from the thermostat to dump the grow air in


That is a good suggestion. I had not yet thought of that. Thank you



			
				bwanabud said:
			
		

> Yes, pull the air into the grow room...then dump it outside. *Unless you want your house smelling like a big sweaty stinky bud *


 
I could think of worse things but I do get your point. My house is not right next to another but I would still like to avoid having anybody at all smelling that and guessing that a grow is going on. One thing that I do understand very clearly is that secrecy is the best policy, cops and robbers and all.



			
				bwanabud said:
			
		

> I'm an HVAC engineer, just figured his grow room was in the basement.
> 
> Running the lites at night will help, but still need fresh air for the plants.


 
Ah, we do not have basements in my area

I have thought about running the lights at night but I fear those helicopters that skulk around in the quiet of the night looking for heat signatures. I think they are unable to do that during the day but do not know that for sure.



			
				Growdude said:
			
		

> He is concerned that the draw from his tent is going to exhaust his AC in the house.


 
Yes, exactly.

I am considering the mini split for the room that the grow room is in. I could isolate the central air from that room. 

Anyway, just to be clear, can I pump the air that is being drawn out of the grow space back into the house and not outside? With a good carbon filter to cut down on dank smell?


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## PuffinNugs (Apr 8, 2012)

Skool said:
			
		

> I have thought about running the lights at night but I fear those helicopters that skulk around in the quiet of the night looking for heat signatures. I think they are unable to do that during the day but do not know that for sure.


 
if your living in the US they dont do this at all, they need a warrent now to use flir on your house, since it now consitutes as a search by the supreme court. if they got the warrent they most likely will be kicking down your door instead.


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## novitius (Jul 19, 2019)

Hmmmm


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