AC creating a ton of negative pressure

Hey guys,

So I have a Whynter 14k dual hose portable ac in my 8x8 tent. The intake is outside the tent towards the ground, and the exhaust is going up to vent that is venting the hot air.

My issue I'm having is that its creating such negative pressure that its pulling all walls and even the floor up like its a damn moon bounce.

Im not sure if my expectations of this AC are too high but my tent is inside of a metal building that has no ac and its not insulated that great. So basically its the same temp inside the garage as it is outside right now(about 90)

Should this thing be able to cool an 8x8 tent in these conditions with 4 315w cmh lights? Right now Im running one light because the plants are still very young but Im kind of worried about when all 4 are on. When I bought the AC I calculated it to the recommended BTU for the room size and lights. I'm guessing I wouldn't be having an issue if the tent were in a well insulated cooler area. Also I feel like its sucking the cold air that it puts in right back out. Should I try to put the intake hose right inside the tent so it is drawing in cooler air?

Any help Id greatly appreciate it. I know these AC aren't that efficient but It was really my only option besides a mini split.

The Only other equipment I have in the room are two hurricane fans and a 6" maxfan

Well....after tweaking for a month with those portable ac I wouldn't raccomend em at all...
You know they are very non efficient and also if they came with the dual exhaust hose they always create some negative pressure....looks like they are not completely sealed from the inside...

For sure the fact that the tent sit in a garage doesent help also....

I solved the problem, studying a little bit on how to install a mini split....its super easy and you can find unit for 14kbtu that are pretty cheap....but remember when it comes to ac don't get fooled by their low cost cause you will rather pay later in electrical cost or repair and assistance...

Good brand are Mitsubishi, samsung, Dainkin....and don't forget to check the max power consumption and the SEER rating. very important!

You could mount the mini split in the garage and ventilate the tent with the cool air of your "lung" room....insulate the garage could be very important too....

Im sorry I can't give you better advice on those portable ones....I hate them....

Just some random ramblings...
It is better to cool the surrounding area (your garage) and pull that conditioned air into your tent.
Like Grapefruitroop said, portable A/C units are quite inefficient.
If you could supply a drawing or photo of your current setup, it might be easier for us to visualize. Without seeing what you are doing inlet/outlet-wise, the first thing that comes to mind is opening an additional vent in the tent to relieve pressure. But then you are exposing it to your unconditioned space.
Regarding mini-splits, the Mr Cool DIY is very, very popular and affordable, and I hear nothing but good things about it.
https://mrcool.com/mrcool-diy-ae/

Another thought - how big is your garage? Is your portable A/C unit powerful enough to cool the garage space?

A mini split would have been the way to go if you have space to mount the unit outside. Most of the portable A/c’s aren’t good for anything except keeping a cool breeze in your living room. The only ones I’ve seen that are worth a damn are typically 2 ton and up commercial units. I have seen a decent 1 ton, but not very many of them, and pretty much all of the consumer based models aren’t worth a damn.

Leaflet said:

Just some random ramblings...
It is better to cool the surrounding area (your garage) and pull that conditioned air into your tent.
Like Grapefruitroop said, portable A/C units are quite inefficient.
If you could supply a drawing or photo of your current setup, it might be easier for us to visualize. Without seeing what you are doing inlet/outlet-wise, the first thing that comes to mind is opening an additional vent in the tent to relieve pressure. But then you are exposing it to your unconditioned space.
Regarding mini-splits, the Mr Cool DIY is very, very popular and affordable, and I hear nothing but good things about it.
https://mrcool.com/mrcool-diy-ae/

Click to expand...

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You can get some portable mini splits but regardless dont waste money on none split AC as everyone here has rightly pointed out..

Funny...
I've been killing it with a single hose portable ac for the last 6+ yrs.

3x600hps, no problems cooling
4x 315 cmh, again, no problem cooling.

It's all I how you set it up.

I would just take the case off a window AC, build a shelf next to the tent, cut a slot in the tent, bend the coil through the slot and into the tent, then patch the slot up around the copper lines. Put an extra fan that blows through the coil hanging inside the tent, to circulate the cold air around.

Then add a duct box mod onto the ac, and vent all the heat outside somehow or even through a window. You could seal the tent up well and inject c02 if you wanted.

If you had an HVAC buddy with tools you could just extend the lines to the coil and then recharge the unit, and hang it in a window like normal, but that's a little more complex of a project..


Ghetto mini split at the fraction of the cost

I love this video of how a guy modified a window unit into a mini split for his van. Suppose you could lengthen the lines to either the condensor or the evaporator coil, whichever one you choose. Or even both? I'm sure more of us here would do it too if we had the skills and access to the right HVAC tools, or a buddy that does..

https://www.youtube.com/watch?v=AXgHIrFqm9o