Dual hose Portable AC unit and long runs of exhaust duct: Booster fan on the exhaust?

I recently purchased a 14,000 BTU Hydrofarm Active Air portable air conditioner and I'm having some trouble figuring out how to go about exhausting it. This unit will be standing in the basement so windows to build an exhaust port into are far away from the unit. To place it where I need it, I need to run around 6-7 feet of duct from the intake window to the AC unit and about another 12 or more feet of duct to get to the window where the exhaust port will be.

My understanding is that these units are MUCH less efficient at cooling when they are setup with long runs of duct work. Would it be feasible to get a 6 inch 235 CFM booster fan from Home Depot to put inline about halfway down the exhaust side duct line. I have no idea what the AC's built in exhaust fan is rated at in CFM's and I can't find it anywhere online.

Also, if I did connect this 235 CFM booster fan, wouldn't I need to connect it to a relay of some sort to get it to turn off when the AC turns off? Or could I get away with running the booster 24/7 even when the AC kicks off or would it cause some type of damage to the AC's fan? Would I need to install a speed control to the booster so it isn't constantly running max speed, or is it ok to have airflow running through the AC even though the AC's exhaust fan is off?

I am WIDE open to any suggestions, criticisms or insults heheh. Please help!

I have a 14k soleus and a 14k edgestar both dual hose. both draw some air from in the room. So I hope you don't have close neighbors or that you are not going to run co2.

As far as the long runs, It can be done I added a 6inch high velocity 400cfm fan to help push the air out. Make sure you put it on the intake side though cuz the high temps from the exhaust, often close to 150deg f, will fry the bearings.(I know from experience unfortunately)

I had mine operate on a thermostat.http://www.ebay.com/itm/Attic-fan-Thermostat-NEW-/171045465849?pt=LH_DefaultDomain_0&hash=item27d31aaef9
Placed on the exhaust duct. I screwed it right to the steel duct and insulated all around and up to it. When it heated up the booster kicked on. I would also recommend running insulated duct to prevent the heat from transferring back into the room.

Thank god I got a minisplit for this ac season. My 3 ton minisplit pulls only 3 more amps than either 14k dual hose.

Good luck brother. hth

hey si, how did this ventilation issue resolve?

Return it and get a mini split, those portables aren't worth the electricity it takes to power them.

I would love to hear as well. I am new to growing and trying a similar set up… Just purchased the same active air unit as well.

been working on this myself

1 u need to contact the makers of this and ask them what the CFM rating is the exhust on their unit
A if u use something stronger then the oringal output u will cuase the oringal to spins faster ( was not designed to spin faster more stresses and force something fails )

2 if u are planning on hook a y spilt in to exhust out ...........u need to have a fan sucking at the 1 point (if u try to balance out with 2 blowing pressusre it is almost impossible one of them will always push back draft down the other )

so if it is a 2 duct exhust use a Y at the end and then attach the fan to suck down both ..............u might need a reducer from 6 to 4 since 4 offers 100cfm 80cfm and 170 cfm...............u need one to add up to the power of both of those exhust or only 80/90% of the power for that fan at the end of the Y

I ended up hooking up a 6 inch 435 CFM inline fan to the intake. The way it was configured, it was pulling air from outside of the room and forcing it through the AC and out of the house. Never ran into any problems.

As far as the person who says portables aren't worth the electricity, my garden would disagree, the portable worked just fine to keep 4kW below 85 degrees even on the worst days of the Summer. Even when it was 100 degrees outside, it was only 85 max inside. I know that portables are a bit over rated and mini splits are twice as efficient but not everybody can afford to fork over $1000-$2000 to get a mini split.


I never had any issues with smell outside of the house but I was lucky enough that a friend gifted me a 5 foot tall 18 inch wide carbon filter with a 12 inch inline fan. That did the job as far as smell control. Of course the filter and fan were big time overkill for a room of it's size so the odor never had a chance. I imagine without a large enough filter and fan, the smell would have stunk up the entire neighborhood.

Joe MacClennan gave good solid advice.

Justugh, I can understand the concept of your first point of the external blower pushing too hard and causing "the wheels to fly off" so to speak but not if you're just using a simple 6 inch 435 CFM fan. The A/C blower was rated much lower than the external blower yet I never had any issues and the A/C is still kicking strong to this day after a solid year of constant use even through the stressful Summer days that cause the unit to run all of the time to keep up.

I still haven't been able to afford a mini split but a friend of mine sold me a 14,000 BTU? Soleus portable AC/heater and now I have 2 of them running and it keeps 8kW nice and cool at about 78 degrees in the flower room when it hit 90 degrees outside. I suppose it hasn't really been put to the test quite yet considering I am yet to see those 100+ degree Summer days that are on the way.

They have mini splits from around $450 and up now.

ok man then just add on to give yourself a little bit of play room

u have 2 of them now ...........why not make a few swamp coolers to just run so those kick off more offen and lower your price......if heat becomes a issuse they will run all the time and the cooler will add in to keep it just where u need it if at a important time

add frozen jugs of water in the center for those 110 degree days ................between that and those 2 u have u should be more then covered ........it just your engery use is going to be high

if u got the money might think of getting a bank of solar pannels or a wind turbine to off set your engery needs and make it little safer for u ............pulling to much power is anouther reason they can add on to why they want a warrent to come in

edit..........in theroy if u can have them rasied up so they suck in the hot air it would be more effective but i do not know if u have some place to set it with out losing ground space for a plant ..........i would not hang it unless u are tied into wood beams and then a 4 point attachement system to bucket (1 gallon of water is 8 lbs)

justugh said:

ok man then just add on to give yourself a little bit of play room

u have 2 of them now ...........why not make a few swamp coolers to just run so those kick off more offen and lower your price......if heat becomes a issuse they will run all the time and the cooler will add in to keep it just where u need it if at a important time

add frozen jugs of water in the center for those 110 degree days ................between that and those 2 u have u should be more then covered ........it just your engery use is going to be high

if u got the money might think of getting a bank of solar pannels or a wind turbine to off set your engery needs and make it little safer for u ............pulling to much power is anouther reason they can add on to why they want a warrent to come in

edit..........in theroy if u can have them rasied up so they suck in the hot air it would be more effective but i do not know if u have some place to set it with out losing ground space for a plant ..........i would not hang it unless u are tied into wood beams and then a 4 point attachement system to bucket (1 gallon of water is 8 lbs)

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Well hopefully I will have a mini split soon and I won't have to worry about it. I've used swamp coolers before but I think in a space as large and open as mine it would be a waste of ice and electricity to run one or even two.

I would LOVE to have solar panels fueling everything but thats an expense I won't be able to afford for a very long time. Myy house needs a new roof and my basement plumbing needs about 10K worth of repairs. I have a feeling it's going to be a couple years before everything is fixed.

And with the way my neighborhood has been lately, I just want to get the hell out of the city and move to the countryside. If I didn't have family to take care of here in the city, I would have liquidated all my equipment and headed for the hills to live off the land. Theres little punks kicking in peoples doors, killing the residents, and robbing the houses around here. I just want to leave.

As far as my electric bill and police, I have nothing to worry about. I stay well within my States legal regulations and I am licensed by my State Department of Licensing and Regulatory Affairs. I am extra diligent when it comes to keeping track of weight and plant count. It's all good around here though. When police in my area get wind of a grow, they go right up to your door and do a "tap-and-rap" or "knock-and-talk". They bluntly tell you that they have suspicions of somebody growing cannabis and give you a chance to show your licensing before taking you down. Apparently, the State is fed up with wasting resources on raiding legal grows. Turns out that 95% of grows raided in Michigan now, are 100% compliant with State law. They just can't justify the use of resources with zero return. Also, personal recreational cannabis possession up to 28 grams has been legalized inside Detroit city limits so I can legally possess up to one ounce of cannabis for personal consumption.

Hell, even before the medical laws passed, the police here didn't care about ganja. The police would literally drive right by us while smoking a blunt in the middle of the street and all they would do is wave or nod at you. I've been caught with weed by the police at least a half dozen times and only once did they make me stomp my herb into the ground. Every other time, they let me keep it and walk away free to go home and get high.

Of course this is all in Detroit, where police have plenty of REAL crime to worry about without destroying peoples lives because of a plant. Police just don't care about weed anymore around here.

Heres a nice example of the progress that has been made in Michigan

your in kill city

dude pack the shit up move the hell out before the police strike from lack of payment and under armed

Anyone know the best place to get a mini-split? Online home depot? Also, does anyone know how far the outside unit can be from the inside air handler? How long can the cord go that attaches them? The only good place for me to put the outside outdoor thing is around the corner from the room the handler will be in. I plan the bury the connection tube and have it go around the corner of the house… maybe 40 feet total. Is that feasible?

Home depot shows universal piping assemblies that go up to 50 feet… and are 1/4" by 1/2" (so I would only need a 1" diameter hole drilled into the room?). They are very expensive though. $449 just for the 50 foot piping assembly. And can these be buried and run underground? Thanks for any help. New to this. Anyone recommendations on units/brands? Thanks

superstoner1 said:

They have mini splits from around $450 and up now.

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yep....the price has came down substantially. Well worth the investment imo.....The extra money will be paid back in energy savings in the first season.


@ strainlover.....anything that has mitsubishi on it is top of the line.

Air Con is an off brand that is pretty nice equipment. Make sure you upgrade to the all copper linesets.

but all minisplits need their linesets and evaporators evacuated, so some knowledge of ac is essential for the equipment to last more than a couple of years.

but a set of gauges, and a cheap vacuum pump from harbor freight will get you there.


good luck ppl.

Thank you for the pointers Joe

yw strainlover....I like to help where I can