mini split vs wall unit ac in sealed CO2 room

20ft x 10ft grow room setup with 2 approximately 800 watt LED frames running on a 5x10 tray.

our 9000btu mini split took a crap after a very short run. and was considering just running a window AC unit

can I keep the room completely sealed with a window unit?? the split did a great job of keeping things air-tight to limit smell leak into the rest of basement room.

I can get a window AC running for half the price of a new split. but im worried they might leak too much. was considering a saddle style to cut down on the amount of hole in the wall space to help cut on leaks from the unit itself once installed

I have a split, zero leaks fill hole with expanding foam.

semaphore said:

I have a split, zero leaks fill hole with expanding foam.

Click to expand...

It was the window ac in the wall that I was curious would leak. I used a split very successfully, but it only lasted 2 grow cycles and suspiciously died.

With some mods its possible to seal a window unit up better. The saddle units are probably even easier, and are built more like a split from the get go.

Big issue is the wall ones Inless this is being installed not in window the temp limits is gonnea suck exp in winter. Remeber they are making these units for cooling ur house and people don’t need a/c for winter . many modern mini splits can be very cold enviroment OD’s and still function. As a side tip keep the a/c’s water drain cause if ur in a cold area that drain can and will freeze on the end and be major issues also. my deh to a/c is a lot of my % of usable water and every gallon saved is a great thing .

That's a good point, are you running it in winter and did the water drain freeze, causing it to fail prematurely? Do you mind telling us the brand of mini-split it was so we can steer clear of that one? What a ripoff it breaks so fast that SUCKS.

Sorry, don't know the answer to the initial question. Seems window shakers usually have the vent vs no vent button which is a sorry version of a vent that lets fresh air in when open but doesn't close all the way, so I'd think smelly air escapes esp if you have positive pressure due to the ac and no odor control blowing out. But I can't say how noticeable it would be.

a regular a/c pushes hot air outside it will stink around the a/c. i would just get the mini split repaired. its a pain in the ass removing the air handler repairing drywall, vac'ing the refrigerant to a reclaim tank, and removing the condenser from the building. as well as disconnecting and removing the 240v circuit for the split. i say repair the split. did it leak refrigerant or something?

If co2 is the only concern with a window ac then don’t worry about it, its not going to leak enough to make a difference

You can turn a window banger into a split unit, simply by taking it apart and carefully bending the evaporator coil out and away without cracking the copper lines. Then stick only the coil into your grow room or tent through a notch in the wall, and seal the pipes back up. Add another smaller fan to the same circuit, that blows through when its on and only circulates in the space you want it to, without mixing any outside air. You could still install it in the window, and then cover it with a box like panel, with only the coil sticking through.


Or, you could simply duct mod the condenser coil section (if you wanna leave the unit inside closer to the grow room) and send the heat through a longer duct and out the window with another inline fan. That way it doesn't have to sit in the window where it might freeze up during winter use. You'll lose some efficiency though, as having the condenser and compressor outside will always be better than inside, unless of course it would ever freeze up...