I didn't do anything to cool the gas, when half of my base freeze, most extreme temp on the screen. but it is also very cold ~-50* to the right of the door.
I am using wheezeworths to cool CO2 as you see, but the room is separated by water and CO2 is only -35*C.
Edit: there is a wheezeworth seed near rejuvenator. I think it is cooling the air, although it is not planted.
I've eventually became bored with my duplicates and decided to give them WW1 treatment. IMAGINE MY SHOCK when not only they walked out of licquid chlorine shower like nothing happened, but also shower continiued to output contaminated water. Works same with lavatory.