Dual Hose A/C

Zeez · Jan 29, 2018

Anyone have a recommend for a dual hose a/c. I've read allot of bad reviews. Also read that extending the hoses voids the warranty, which led me to think that a couple of helper fans inline would help cool the hot side of the a/c. A mini split would be great, but it's going in a 5x9 tent not a room.

Chunkypigs · Jan 29, 2018

I think you'll find it easier and much cheaper to cool your lung room with a window unit and keep your tent cool with exhaust fans strong enough to exchange the air rapidly in it with the lung room.

it's tough to cool these new non air cooled fixtures that have the ballasts attached when you hang them in a tent.

I use 2 8" fans to keep my 4x 8 cool with 1200 watts.

Zeez · Jan 29, 2018

It's in the cellar so there's no way for a window unit. The reviews on portables are so bad, It's tempting to build a box to hold a window unit and duct cooling air to and from it with duct fans. The ballasts are outside, but there's a dehumidifier in there.

Drop That Sound · Jan 30, 2018

Ya don't get a portable, they don't barely work even if you shorten the stock hoses going to a window.

Do you have a decent sized closet or room down there with a door on it? Could mount the window unit right through the door, seal it up nice, and put a large extraction fan near the ceiling in the closet. 8" for sure. Some kind of intake would be needed, maybe just a smaller vent on the same door down below the unit. Doors are cheap to replace. Or start with a used one that fits.

If you don't, then turning a window unit into a portable by hooking up ducting definitely works. Better than a portable. Again use 8 inch coming off the diy unit. Bulky but needed.

I wish I had HVAC tools, watch this guy convert a run of the mill window banger into a mini split in no time: https://www.youtube.com/watch?v=AXgHIrFqm9o

Chunkypigs · Jan 31, 2018

Zeez said:
It's in the cellar so there's no way for a window unit. The reviews on portables are so bad, It's tempting to build a box to hold a window unit and duct cooling air to and from it with duct fans. The ballasts are outside, but there's a dehumidifier in there.

what size fan filter are you using to cool the tent?
why do you have the dehuey in the tent? does it run during lights on?

you have a logging system running in there on your temps/humidity?

humidity here has been crazy low and leaving the bulkhead door cracked 1/4" has been keeping 2200 watts cool in the cellar here so far for me.

Zeez · Jan 31, 2018

Hi Chunky, For winter ops it's 6" with 350cfm fans in and out using filtered outdoor air. The dehuey is mainly for the humidity rise after lights out, but covers high humidity days as well.

All temps and RH are logged and can be viewed in hour, day, week, month, or year and can be exported in excell. Check out a gizmo called Sensorpush. Cheap and excellent.

Chunkypigs · Jan 31, 2018

how does your current report look there? what's the issue you're having that you want to run the AC in the winter?

I had trouble with stressed plants when cooling with winter air in my NY grow and had to recirculate house air though my closet once temps got below freezing outside.

they could handle 40 degrees but below that plants like the glue hermed on me.

Zeez · Jan 31, 2018

The current setup is working well. No issues except for a fan failure a few days ago. I want to have the new a/c setup ready to roll by the end of march.

Chunkypigs · Jan 31, 2018

It looks like the temps are good.
Does the fan blow outside air through during lights out too? Is it on a thermostat or timer or just constant?

Zeez · Jan 31, 2018

Fans are on a temp control set at 73 with a 3 degree cycle. I get a big humidity bump after the lights go out with the temp drop causing the rh to spike. Lights are CMH with no cooling.

Chunkypigs · Jan 31, 2018

Have you ever tried using your cellar as a lung room? You will get rid of that problem with humidity spikes and get your dehuey out of the tent. Use the same fans to cool the cellar not the tent. Turn the air in the tent over so fast it doesn't hold any heat or humidity above the lung room.

Your cellar got bulkhead doors to the yard?

Zeez · Jan 31, 2018

The whole cellar is too much. Keeping it contained in the 5x9 sealed tent with controlled temp and humidity is my goal. Maybe a small mini split is the way to go.

Zeez · Jan 31, 2018

I got a 55 gallon storage bin and a 12,000 btu window air conditioner. The bin will get a hole cut in the side of it to fit the rear of the air conditioner and holes in each end to attach 8" flanges. Flex duct and two 870 cfm fans will provide cooling for the hot side of the air conditioner in the bin. The a/c will also sit on wood in the bin allowing for free flow cooling air.

If the a/c can be run for a week in the bin with reasonable temps , the tent will get a hole cut in the side large enough for the front of the air conditioner. Doing it this way keeps the tent a sealed or lung room and gives much better performance than a portable a/c unit.

I will post pics of the project and temp data to show the viability of this method. As far as cost, this is about half the price of a dual hose portable a/c or a quarter the cost of a decent mini split. The 3 year a/c warranty was $30 in case the window unit fries.

Chunkypigs · Feb 1, 2018

Zeez said:
I got a 55 gallon storage bin and a 12,000 btu window air conditioner. The bin will get a hole cut in the side of it to fit the rear of the air conditioner and holes in each end to attach 8" flanges. Flex duct and two 870 cfm fans will provide cooling for the hot side of the air conditioner in the bin. The a/c will also sit on wood in the bin allowing for free flow cooling air.

If the a/c can be run for a week in the bin with reasonable temps , the tent will get a hole cut in the side large enough for the front of the air conditioner. Doing it this way keeps the tent a sealed or lung room and gives much better performance than a portable a/c unit.

I will post pics of the project and temp data to show the viability of this method. As far as cost, this is about half the price of a dual hose portable a/c or a quarter the cost of a decent mini split. The 3 year a/c warranty was $30 in case the window unit fries.

the viability of that has been tested before here, basically you are proposing to recreate a portable with bigger fans.

as soon as you see the issues with condensation your system will have in those flex hoses and plastic box you will understand why more folks are not doing this.

you should be able to find a handful of old threads on this from the time tents 1st got popular.

cooling a small tent with a window AC never caught on for a reason, too hard to control climate in such a tiny space if it's sealed up and running with a dehuey, big overshoots in temp and humidity and the only way to make it work is to add lots of heat during lights out.

it's why you see lung rooms utilized for smaller grows like yours with AC's.
they work best when you use 2 flowering chambers with lights on times opposing each other so there is a constant level of heat and humidity to control as opposed to huge 12 hour spikes if there's a single tent or flowering space.

this is an easy way to make a windowbanger work in a new england cellar.
build a small entryway at the bottom of the stairs and use that space to exchange air with outside.
you might need to add vents on the sides of your door enclosure outside and possibly a fan if you want the metal doors to stay closed with the AC running in the summer.

I use a bit of 2x4 to put upward pressure on the bottom of our latched bulkhead doors which gives me security and an air gap that lets circulation happen.

if your cellar is something so huge that you don't want to cool it all just frame off a chunk of it to use for your lung room and weed lab.

might be easier to use one of your upstairs rooms that has a window or 2 for AC's to grow in or put the mini split in the cellar and have real control over your environment down there.

be careful, it's real easy to turn your house into a big black mold factory when you get enough plants growing in it without real climate control.

if you see condensation on your windows in the winter you are growing mold elsewhere.

Zeez · Feb 1, 2018

I see your point. Plants, water, transpiration and cold cellar walls can easily add up to mold. The more air you bring in, the more moisture, and the cool cellar walls cause condensation. Even if it's not dripping its there.

The best terms for searching were "AC Box" and several results came up in ICMag. There were several similar applications, but none quite the same. There weren't any that approached cooling the hot side of the a/c with serious air flow like two 8" fans. That much flow should take care of condensation. Dual 870 CFM fans doing push pull on the a/c box. Even if the imported outdoor air is saturated and raining, it should get cleared out with clearing weather and a wider dew point spread. In this case, the basement exhaust window is just a few feet from the box.

I'm pretty much stuck with the 5x9 tent and for my purposes that's plenty of room. The small mini split would really work, but this is just a relatively small operation and not like a room. Its worth the gamble and going heavy on the exhaust system to make the ac box work. The condensation can drain out int a condensation pump and get pumped away. I already use those for returning excess nutes and the dehuey drain.

Drop That Sound · Feb 1, 2018

The bin is a cool idea

If the flexible ducting was always at an incline vertically it would all drain back down into it. At least on the inside of the ducting. Insulated might help for the outside to stay dry. I would use rigid ducts on any horizontal run so moisture would'nt get trapped like in the ribs.

Zeez · Feb 1, 2018

Great ideas DTS. I'm going to use them. The cooling air will come in the side of the bin and out the top, straight up to the window with rigid duct. The a/c has a drain plug for a hose and it would probably be good to have a drain in the bin too angling towards the drain. Warm air holds allot more water than cold, so with the air flow and these ideas it should be good.

Drop That Sound · Feb 1, 2018

Sounds good. I've checked out all the AC duct mods too. They all skimped on the fans though so you should be good on that part.

I've seen one's where they just use 2 ducts off the back. Also where they remove the stock fan from the shaft and hook 1 duct on the back and the other on the side where the intake is, so it flows through the condenser coil better.

I guess either way will work.. were you just gonna cover the sides off and let the fan circulate the bin?

Also, theres no reason you couldn't add another bin to the front, and do the same thing on the cold side. Then you could duct it into the tent remotely without cutting a hole. Insulate it real well.. Might as well cover the tent with some 1-2 inch rigid foam panels while your at it.

Like chunk said though you might need more equipment to make up for it, and have a few issues to work out as far as the environment and condensation isssues go's. Could make a cheap partition wall with panda

Which leads me to another few idea's. More mods to the unit (or future ones anyway) could turn it into a dehuey/ or even a heat pump. Different functions at different times. Motorized dampers could switch the flow so your exhausting cold air, etc. One window banger that does it all.

If you scrapped the main housing and spread out all the internal components onto a pallet, you could lay the bins right over top the coils upside down. Careful not to kind any lines. Then you could really get at it.

Luckily for mine i'm able to vent the back of my unit directly out of the wall, and without it actually hanging outside. Louvers with a bug screen on the exterior. My flower room is literally right next to the cabinet that the unit will sit in (in my work room), and im going to cut a notch in the flower room wall so i can bend just the evaporator coil into it.

I was gonna duct it in a different spot, actually taking up more space, but you can't beat a $150 mini split type setup..

Zeez · Feb 1, 2018

I saw your post in the AC Box made easy thread. Cool ideas! This is a 5x9 Gorilla tent. I don't have a problem cutting a hole in the tent side once it's proved that the two 8" 870cfm fans and ducting are enough to cool it. That should be allot of cooling air. Two more fans to save the hole isn't worth it and could bring down the efficiency. The big thing for me is, It's got to work and keeping a sealed environment mainly for the CO2. Funny thing is, Even if you go for the whole enchilada - heat pump heating / cooling, this approach is a cheap way to go.

This is a 3 light 315 CMH setup with a dehumidifier inside the 5x9 tent. A 12k btu should be good if there is enough cooling air. I saw other posts where guys were doing 4k HPS with 12k and loving it. All the threads on ac boxes, I couldn't find anybody who said it didn't work or ones who had problems with mold in the system. Only problems seemed to be not enough cooling air or too small ac unit. In this case the CMH lights don't make a crazy amount of heat

Right now I'm running filtered outdoor air for cooling. Some people were using this type of setup to vent the room after lights out to get rid of the moisture rise. Maybe going to Tee the ac cooling into the existing cooling system with a motorized damper to make this possible. (already have the motorized damper and spring loaded butterfly dampers) It might make the dehumidifier work less after lights out and shorten the humidity bounce.

Really good advice. Appreciate the insight and experience.

Zeez · Feb 3, 2018

Drop That Sound said:
Sounds good. I've checked out all the AC duct mods too. They all skimped on the fans though so you should be good on that part.

I've seen one's where they just use 2 ducts off the back. Also where they remove the stock fan from the shaft and hook 1 duct on the back and the other on the side where the intake is, so it flows through the condenser coil better.

I guess either way will work.. were you just gonna cover the sides off and let the fan circulate the bin?

All good stuff.

What do you think about blocking one side of the a/c and baffling inside the bin so more of the cooling air goes through the condenser? It would restrict the overall air flow. The thought was that too much undirected air going through the bin could take away from the ac fan that blows through the condenser.

Dual Hose A/C

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