Moving to basement, CO2/Ventilation questions...

Hi guys I am moving to a new house and so my environment for my plants is about to change fairly significantly. I currently have a 400 W metal halide and an 8 lamp hydrofarm T5 light in my veg room. For flowering I have a 4x4x6.5 tent with a 600w HPS in a cooltube w/ carbon filter, and 6" exhaust fan. I am going to be moving all of this into a basement storage room that is sealed. The room is fairly small- 8 ft wide, half the room is 7'bout tall and half is 4', its about 15 feet long. SO new problems are temp control and ventilation. Venting is basically not an option as the owner (my friend) would not be willing to allow me to cut vent holes or modify the grow room this way (anal about his new place/first home). So I was thinking about purchasing a propane CO2 generator. From what I understand about ventilation its purpose is to remove heat and bring in fresh air (CO2). With a higher amount of CO2 in the air the plants can withstand higher temps and have all the CO2 they need. Would this remove my need to ventilate? Any ideas on best way to adminster CO2- I want to be able to circulate the CO2 between the veg area of the room and through the grow tent as well. Any other problems you think I may run into?Thanks in advance for any help!

with out venting the temp will rise and co2 will rise but it can rise fast and get out of control fast use a fan to move the air around and open the door to allow fresh air in the room once in a while. plant can only go up to 1500-1750 ppm of CO2 in the air no this wont kill you but in the long run can hurt when trying to get the humdity right if it is two high.

you are right on saying that co2 generation will allow higher temps (up into the low 90s is not unheard of) but a 600w lamp in a sealed space with no cooling will produce temperatures well over 100 degrees! if you check out sealed co2 grows, youll see most people have either an a/c unit in the room or a temperature controller which turns on exhaust when temps get too high. even with a portable a/c unit though, you need at least one hole to vent out the heat the unit removes. maybe try buying a new door to this little room and cutting your exhaust into that, then replacing the door when you move out?