Best air con for my set up; HELP

So here is the layout.

There are 2 flowering tents running a max of 550 watts of quantum boards, fans, and exhaust. They are in a 7’x16’ room with 14’ ceilings (almost 1600 cu ft). The tents run from 9pm-9am for temperature reasons. During this time, outside ambient temps can range from 90f to the low 60’s. Temps within the tents reach the low 90’s. The tent is usually within a degree or two of the room it is in, due to my mass exhausting (180 cu ft flow for less than 75 cu ft of tent). There is a central air dump in this room, but the thermostat is located in another section of my house that is completely closed off to this room, and I would have to freeze the rest of the house all day to cool this room. The room is currently 90 with no ac and no lights on.

To deal with the heat, I have taken several steps, all with such small gains that the totality of my efforts is barely noticeable.
1. I mounted the drivers outside of the tents. I saw a slight drop in average temp within the tent, even when ambient night temps were slightly rising; less than 2* guesstimate.
2. I have 200+ cfm capabilities to vent the tents. I currently dump the heat through a security door window that goes outside. Fresh air (and some recirc obviously) enters through the security door window, the tents intake this air, and the exhaust fan dumps it back out the door. This was the best move, but it’s still too hot.
3. I open the window to the security door. During my run time, the outside temp is cooler than the room 99% of the time. Sometimes only a few degrees, but I’m taking every passive bit of cooling that I can get, at this point.

As far as I can see, I have only a couple options. Please keep in mind that focus of my set up is efficiency. I use quantum boards, usb fans, and an ac infinity 4” inline for maximum efficiency. Power is 28c/kWh for me, and this is only a temp summer set up until it cools down in late September. I just need something to carry me until then AS EFFICIENTLY AS POSSIBLE when taking into account both purchase and RUNNING costs over maybe 3 months.

1. Window ac with custom mount for the security door. These are supposedly the most efficient of the small air cons, but how efficient it will be during cooler outside temps is questionable. How well will it cool my room when it’s 60* outside, but 90 in the room?

2. Dual hose ac. Again, reliant on outside temps, correct? How well will it cool when it’s still 90* outside, and my room/tents are 90?

3. Single hose ac. It pulls air from inside which is inefficient as all hell, but I saw a video that shows it is better at cooling a room that has an internal heat source, something that a dual hose has trouble doing.

HVAC gurus? Am I making a mountain out of a molehill for maybe 3 months of cooling?

Here is a link to the video I saw:
 

cindysid

Well-Known Member
I've had lousy luck with the portables. They are inefficient compared to the window units..by far. I want to switch to a multi zone mini split as soon as I can afford it, but I'm using window units at present. Mine do fine in cooler weather. It only gets down to the 40s here, but I've never had a problem with it cooling properly.
 
Dude first thing I would try,is get rid of 4 in exhaust and move up to 8 or more
Well my air movement doesn’t seem to be the problem, since my tents temps are always close to the temp of the room it’s in. It’s a 2x4 60” tall and a 20x36 that is 72” tall. I thought it was small enough for a 4” ac infinity, but I am traditionally an outdoor guy, so the indoor world is a little fresh to me. My exhaust pulls like 25 watts at over 200cfm. Not really trying to push the wattage much higher.

For max efficiency you want a minisplit.
Definitely, but I really don’t want to punch a hole in my wall where I would need to in order to install the air handler. Also, this will only run from June-September, MAYBE a week or two into October before my outside temps are low enough again. I don’t really want to fork over $2k for a decent mini split and licensed install to run ac for 4 months at a time if I don’t have to. At that rate, it would take me years to break even.
 

Renfro

Well-Known Member
Well perhaps a used AC unit off craigslist. Might not be the most energy efficient but the purchase price would be low.
 

Renfro

Well-Known Member
2. Dual hose ac. Again, reliant on outside temps, correct? How well will it cool when it’s still 90* outside, and my room/tents are 90?
Well I have a dual hose portable, actually 4 of them. They all work great when it's 100 outside. I have two that are supposed to blow the condensate out with the hot air but only one does it all the time.
 

Ventryjr

Member
It seems you have central a/c. You may have dampers in the duct work (valves for the air) usually near where the round comes off the square duct work. You can close this partially to the other rooms and leave it more open to the grow room. Causing your a/c to move more air to the grow and run longer in order to keep the thermostat room down to temp. Also closing the registers in other rooms can help a bit. This is called air balancing.
 

Flatrate

Well-Known Member
FWIW I have a portable in the room of my tent, its one of those single hose jobs. It is pretty powerful and can cool my grow room and a couple other rooms quick, its rated for 1500sqft I believe. I don't have central air, large old house so I just cool the rooms I need to. Mine is suppose to also be a 80 pint dehumidifier, yea.......bullshit! In DH mode it sucks, my 30 pint stand alone dehuey will run circles around it.
 

Apalchen

Well-Known Member
I don't understand why the room the tent is in is 90 degrees with out the lights on if you have central air. That being said I've run window AC all winter long and it kept on working just fine. It's been a long time ago but I still remember thinking that my neighbors were gonna think I was crazy cause I had to switch out window units in the middle of winter.

If the rest of your house is cooled by your central air then it seems like you could vent the room the tents are in and Intake from a cooler area of your house. Have the intake running with duct work right into your tents. I mean your dealing with less than 2000 BtU of heat and since your running at night your home system should be able to provide that many btu no problem.
 

Apalchen

Well-Known Member
Okay tried to edit my post but won't let me atm. First and cheapest thing I would try would be ducting your intake air from another room that is cooler. Might not have to do anything else.
 

Renfro

Well-Known Member
Do you have any pics of your setup? It is odd that you are having such a hard time cooling 550 watts of QB.
 
Should cool the room pretty well regardless of your outside temp.

No. Unless your outside temp is getting above 120.. Your outside temp matters very little.

No. A dual hose portable will outperform a single hose in every aspect.
Not according to the video I posted. Just wondering how much the numbers presented in the video actually matter. It showed the dual hose ac outperforming a dual hose when a heat source was located within the room.

It seems you have central a/c. You may have dampers in the duct work (valves for the air) usually near where the round comes off the square duct work. You can close this partially to the other rooms and leave it more open to the grow room. Causing your a/c to move more air to the grow and run longer in order to keep the thermostat room down to temp. Also closing the registers in other rooms can help a bit. This is called air balancing.
The dampers in the room with my tents is closed. I usually run it closed all day, because when the damper is open and the room is being cooled by central air, it never gets below about 85 due to the high ceilings and my wife setting the thermostat at 80 fmy kids get cold).

I don’t really want to open the damper for the grow room and close the other 9 dampers in the house every night, nor do I have the ability to do that since I’m in and out of town all summer. I’m looking for the best way to cool this specific room only, since I have 24/7 access to it. I also need my cooling to take place mostly in the evening/night, so running central air just isn’t feasible. I could buy and run a dual hose for 3 months for what my power bill will be after the first month of central air trying to cool that room with a single register. And again, back to me not being able to open and close registers every night.

Okay tried to edit my post but won't let me atm. First and cheapest thing I would try would be ducting your intake air from another room that is cooler. Might not have to do anything else.
I am considering trying to duct the outside air into my tents and setting it up with a temp controller to only operate during a given parameter. Not sure how this system would operate though.

Do you have any pics of your setup? It is odd that you are having such a hard time cooling 550 watts of QB.
Will try to post some up soon. I’m not even really cooling it right now, just exhausting.
 

Renfro

Well-Known Member
The dampers in the room with my tents is closed. I usually run it closed all day, because when the damper is open and the room is being cooled by central air, it never gets below about 85 due to the high ceilings and my wife setting the thermostat at 80 fmy kids get cold).
Well there is the problem right there, closed damper, no AC is getting into the room with the tent. Thermostat at 80? Yeah you are gonna need a separate cooling system for the grow. You can't get the room any cooler than the intake air if you are planning to vent. So if you have 80 degree air to work with it's no bueno. So that leaves a portable AC for the grow room and the dual hose will be the best option IMO.
 

Renfro

Well-Known Member
The downside to the portable is the condensate drain. So unless you get a portable that exhausts the condensate with the hot air you will want to run a drain line downhill to a drain. Can you drill a hole in the floor and run some 1/2" hose to a basement floor drain? Thats how 2 of mine are setup. I have one that actually doesn't need the drain line since it does exhaust the condensate, the other one thats supposed to do that only does it when it's really hot outside.
 

nevergoodenuf

Well-Known Member
here are 2 flowering tents running a max of 550 watts of quantum boards, fans, and exhaus
Dude first thing I would try,is get rid of 4 in exhaust and move up to 8 or more
Listen to big d. volume is key. Move up to at least a 6" intake fan, not a booster fan. I like Hyperfans, but I think the infinity is also as efficient and comes with a dimmer. You are willing to run a 1400 watt portable AC for 550 to 1100 watt grow. If you run the fan off a temp/humidity controller, you can say even more on electricity.
 
Ok so I hung around the room last night to monitor what was happening once the sun went down and lights came on.

Initial temp in the room was around 88 with the damper open and ac on all day set to 79. Central air is pointless in this room, especially an 8x14 (I think) vent, and the designer of this addition should be shot in the dick with 1,000 BB guns.

With the 4” AC Infinity cranked full blast venting both tents (and essentially the room), I estimated the air flow to be around 170 cfm using an anemometer and several measurements. I think rated is 205 and I have very little ducting, so I think I need to open up my intake. I currently have a light proof 4” intake. When the fan is set to half speed, it’s moving ~100 cfm at 10 watts, but the tents are pulled tight from negative pressure. I will open the intakes tonight and see what happens. Possibly just cover a rectangle vent with “carbon filter” prefilter material?

I should note that I’m growing with led, and have been shooting for 80-83 based on what I’ve read about leds, vpd, and leaf surface temp.

After going to Home Depot and looking at window air cons, I would not be able to fit anything larger than 5000 btu, and I don’t think a 5k will be able to cool the room because of its volume. I don’t want to take the window frame off the door for a window ac to run a couple months. I’m toying with the idea of upgrading my fan to a 6” Terrabloom and using the 4” elsewhere. I don’t really want my exhaust to function on temp because I don’t use co2 and want max air flow.
 
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