Do I need and exhaust fan if I have a ac, heater, dehumidifier.

I just purchase a 4 season machine (air conditioner, Heater and dehumidifier all in one unit) and was wondering if I needed to exhaust the air or can I seal the room. I am asking because I seen in last months high times there was a huge warehouse where the air was never exhausted only circulated within the grow room just cooled and dehumidified. I am running 2 600 watt hps in my flowering area now with exhaust fan. I don't know why I really want to do it like since the unit will more then likely us more energy to run, besides security and better control of my total environment.

any advice or comments welcome.

Better control over your Environment is key. if you can afford the extra cost I would go with a completely sealed room. I'm hopefully going to be setting the same thing up myself this summer. Good luck.

you've gotta figure out the CO2 situation.

Like clown boy said you will need co2 with that you can have a 100% sealed room with no air exchange
good luck bud hope the unit works out for yah

i'll be looking for updates

Chek outmy grow for an example of a proper sealed room with ac, co2, controllers, and dehumidifier. Currently in week 8 flowering lsd and jock horror.

Looking for more responses, I am going to do the same thing

Thanks for the replies. What are my options for supplementing c02. I want to stay away from the burners. And how long on average do the tanks last at proper levels. I would like to implement something that would least last a flower cycle.

can't beat a gas regulator (from hardware store) and a bottle of CO2 from the beer homebrew shop or welding supplier. There are specific grow room regulators with electric solenoids on them which are easier to regulate gas flow, but the welding regulators work fine in my experience and are aeons cheaper.

The benefits of a totally sealed environment are endless. stupidly high CO2 (I have had grows with about 3000-3500ppm of CO2 in the air and had good results. No exhaust has never been a problem, nor has a higher RH% than the suggested 40 for flowering. I have better success using soil than perlite/vermiculite / coco / clay etc in the sealed environment though. Not to sure why, guessing lack of soil oxygenation.

If you have some homebrew beer fermenter in your grow room it also works pretty damn well for not a lot of cash...but a lot of beer (hope you aren't an alcoholic like me )

I have always wanted to harness my own co2 production...go into a small enough grow area and your ppm will go from 3-500 to 1000 in no time! what a waste of gas

A 20# tank will last about a week in the average sized sealed room. that $16 a week plus the PIA of having to swap them out. A ppm controller is THE way to go but they are expensive. Check out my thread about using an on-demand water heater for Co2. Same cost as a bottle system (around $240) but MUCH cheaper and doesn't involve any refills, etc.

https://www.rollitup.org/advanced-marijuana-cultivation/410850-well-fuck-n-tankless-water.html