would this help plants,co2 ques???

[kindindy123]

i was thinking of of way to save on heating rm just a 4x4x6.5, tent & only when lights out, the heater kicks on,what i hav is a exhoust blower set on very low,runs 24/7.what i was thinking was totaly shut down exhoust fan ,and run co2 at lights on,that way kinda sealed enviroment,does this sound like it would make sence.any input would be great thanks