Good one, how often would you be moving lamps around at concerts and parties...
-I don't quote-
Co2 isn't essential for good buds, it is the primary gas that is uptaken by the plant in order for growth. Air, light, and water.
Saying that, you can get much better results by adding co2 to your garden.
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As far as temps rising by using co2, that has a lot of variables, and points of interest.
The optimum temp for co2 absorbtion is quite high, you'll need to stay around 85 degrees, I've seen a few strains
thrive at 90 degrees, but it's not recommended for most strains.
If you want the best results, invest in a ppm controller, one like the ppm2a by CAP has "fuzzy-logic" where it learns the grow room, suited best for tank setups, great product, what i used. There are cheaper models that have a simple on/off relay which does the job, and works for generators. The ppm2a also has the on/off setting.
Fuzzy-logic, it will maintain within 20 points of the desired range, say you want it at 1400, it will learn the room and adjust the amount of time the relay runs, it will click on and off, with short spurts of co2 in order to stay within that range.
An on/off relay would run to 1500, the it will wait until it drops to 1000, then kick it up to 1500... Etc.
If you're using a tank system, there won't be any increase in the temperature, unless you change your ventillation setup.
Co2 works by flowing over the leaves of the plant, so circulation is a must, fans are vital.
If you're using a co2 generator, you will definately need to think about ventillation.
In my experience, I continued to vent my lights into a seperate room, pulling "precious" co2 out of the room, otherwise the temps would be too high, I was using a 850 CFM fan to pul air out, so I surely was wasting co2, I pumped the exhaust into a second bloom room, with only 2 lights, that then vented into the HVAC.