Portable AC + Exhaust and Intake fans

I'm pretty sure I already know the right answer for this but I just need confirmation and suggestions. Those of you that use a portable AC, do you shutdown your intake and exhaust fans when it's on? I have a 10,000 BTU unit that's exhausted outside via its own duct. 10,000BTU should be more than adequate for my space but I find that it barely drops the temperature when it's running. Do I shut turn off my intake and exhaust fans while it's running? Or have them come on for a few mins every hour or so? I'm worried about circulation but I also don't like it when Temps get into the 90s. Any tips or tricks?

Edit: Grow room is 9x15 or so. It’s an outbuilding on my property with decent insulation and no windows.

I'd open a vent at the bottom of the tent... close intake.. (using ac and open vent instead) and leave exhaust/carbon filter on.

Merkn4aSquirtn said:

I'd open a vent at the bottom of the tent... close intake.. (using ac and open vent instead) and leave exhaust/carbon filter on.

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It's not a tent. Its a 9x15 room. I've tried shutting off the intake fan but it didn't seem to change much

Whats causing the heat issue? Summer time or hot lights?

Merkn4aSquirtn said:

Whats causing the heat issue? Summer time or hot lights?

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Summer time temps. I run LED strip lights and they put off hardly any heat at all. At night the lights don’t even put out enough heat to keep the room warm enough. We keep having streaks of 90-100 degree days and my room stays maybe 3 degrees cooler with the AC on high.

id go get a minisplit imho.

Gond00s said:

id go get a minisplit imho.

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I’d rather not. That’s another $1000+ I don’t want to spend and was hoping i could make do with what I’ve got.

Thinking I may just seal this room and run CO2. There’s only maybe 15 or so super hot days here so investing in a mini split seems excessive.

tbh then cant really be helped single hosed units kinda blow and dual will just be fine at that point. I would use a window banger. also that single hosed ac pulls air from the room not worth doing co2 only really worth doing it if its fully sealed aka a minisplit or a window banger. would also like to say the dual hosed still takes air from the room aka losing efficiency.

Gond00s said:

tbh then cant really be helped single hosed units kinda blow and dual will just be fine at that point. I would use a window banger. also that single hosed ac pulls air from the room not worth doing co2 only really worth doing it if its fully sealed aka a minisplit or a window banger. would also like to say the dual hosed still takes air from the room aka losing efficiency.

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Can't run a window banger either. No windows in the structure. Might swap for a dual hose though. Probably won't be a huge deal to let the plants suffer a bit on the hot days. Even when it's over 100 outside I can keep the room in the low 90s. Guess I'll have to play with My fans and see what the most efficient settings are. I feel like if I kill the intake and exhaust when the AC is on I can probably lower temps enough. What's worse though, 6 hours with decreased circulation or 6 hours in the 90s.

Now when you are talking about intake and exhaust vents, are you saying you pull outside air into the room and push room air outside? I would be running that room completely sealed with co2 added. If you have your intake and exhaust vents shut off is the ac cooling the room properly?

sf_frankie said:

Can't run a window banger either. No windows in the structure. Might swap for a dual hose though. Probably won't be a huge deal to let the plants suffer a bit on the hot days. Even when it's over 100 outside I can keep the room in the low 90s. Guess I'll have to play with My fans and see what the most efficient settings are. I feel like if I kill the intake and exhaust when the AC is on I can probably lower temps enough. What's worse though, 6 hours with decreased circulation or 6 hours in the 90s.

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If you are supplementing co2 you can run the grow room completely sealed, no intake or exhaust fans. Look up "growing in a sealed room". You will need to add a dehumidifier. And i would recommend putting a hole in the wall and installing one of these johnnies.

JoeBlow5823 said:

Now when you are talking about intake and exhaust vents, are you saying you pull outside air into the room and push room air outside? I would be running that room completely sealed with co2 added. If you have your intake and exhaust vents shut off is the ac cooling the room properly?

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Yeah. Intake is the old dryer vent hole hooked up to a 4" intake fan. Exhaust is an 8" max fan and can filter piped outside.

I'm guessing the AC will probably work if I kill the intake and exhaust fans but it hasn't been hot enough to try lately. I'll kill the fans now and let the AC run and see what happens.

JoeBlow5823 said:

If you are supplementing co2 you can run the grow room completely sealed, no intake or exhaust fans. Look up "growing in a sealed room". You will need to add a dehumidifier. And i would recommend putting a hole in the wall and installing one of these johnnies.

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I know all the basics about running sealed. It actually wouldn't be difficult to do in here. My portable AC can also be run as a dehu. Before I converted it to a vented grow room I don't recall this room getting very hot but I asnt paying too much attention cause it was just a laundry room.

I could just pull the ducting off the exhaust fan to run as a scrubber and close up the intake hole. Then run sealed with CO2. I've heard of folks using a single hose AC with CO2. Its not ideal and wastes a bit but I think if I'm sealed my temps will stay lower so I wouldn't run it oftern

sf_frankie said:

Yeah. Intake is the old dryer vent hole hooked up to a 4" intake fan. Exhaust is an 8" max fan and can filter piped outside.

I'm guessing the AC will probably work if I kill the intake and exhaust fans but it hasn't been hot enough to try lately. I'll kill the fans now and let the AC run and see what happens.

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Yeah if your constantly pushing the air out of the building, you are pushing all your ac out too. Look up running a sealed room and do some learning before you do it, I know there are some things that can go very wrong very quickly if you dont know what your doing. Looks like you just have a couple sprouts right now so co2 isnt a big issue but it will be when they get bigger. Basically what you are doing now would be like having your central air on and all your windows open on a 100 degree day and wondering why your house isnt getting cool

sf_frankie said:

I know all the basics about running sealed. It actually wouldn't be difficult to do in here. My portable AC can also be run as a dehu. Before I converted it to a vented grow room I don't recall this room getting very hot but I asnt paying too much attention cause it was just a laundry room.

I could just pull the ducting off the exhaust fan to run as a scrubber and close up the intake hole. Then run sealed with CO2. I've heard of folks using a single hose AC with CO2. Its not ideal and wastes a bit but I think if I'm sealed my temps will stay lower.

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Like someone else said, they do make in room air conditioners that have intake and exhaust vents which would help with not wasting co2.

JoeBlow5823 said:

Like someone else said, they do make in room air conditioners that have intake and exhaust vents which would help with not wasting co2.

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Yeah I'm familiar with those. I can probably rig the unit I have to do the same or just buy a new one. My girlfriend would probably be happier if I used the single hose AC to cool our bedroom instead of a shed.

I'd likely run a generator over a tank so I wouldn't worry too much about waste since the AC would be used sparingly.

sf_frankie said:

Yeah I'm familiar with those. I can probably rig the unit I have to do the same or just buy a new one. My girlfriend would probably be happier if I used the single hose AC to cool our bedroom instead of a shed.

I'd likely run a generator over a tank so I wouldn't worry too much about waste since the AC would be used sparingly.

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I think sealed rooms do need a very small amount of fresh air anyway but i could be wrong on that.

JoeBlow5823 said:

I think sealed rooms do need a very small amount of fresh air anyway but i could be wrong on that.

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From what I'm reading they should be vented a few times a day. I could just install a flap to redirect exhaust outside when needed.

God dammit, I thought I was done building this room! Now I've gotta go spend more on CO2!

sf_frankie said:

From what I'm reading they should be vented a few times a day. I could just install a flap to push outside when needed.

God dammit, I thought I was done building this room! Now I've gotta go spend more on CO2!

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Yeah thats how it goes with growing.... your never "done" building the grow room.

JoeBlow5823 said:

Yeah thats how it goes with growing.... your never "done" building the grow room.

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Yeah this is my first run and that's become exceedingly clear. I keep waking up in the middle of the night with new ideas. I've been "done" like 6 times now. I'm still way under budget at the moment so it's not a huge deal yet