The idea of using CO² is to raise the level above 1500 ppm and hold it there for an extended period of time so the plants can process the extra amount. They do like warmer temperatures and can process CO² better when the temperature is around the mid to upper 80's but not over 92f.

Most growers have AC systems in there grow areas to provide the cool air to keep the lights in check. You will also need a fan in the room to keep the air moving and disperse the gas around all the plants.