Adding co2 to my greenhouse, worth it?

I have roughly a 20x12 lean to greenhouse and I was thinking about adding a c02 system, like a propane burner most likely. My question is, if I spent say $500ish on the complete setup would I make my money back and more (or at least have it pay for itself) with the plants I have now? There is about 3 giants (7 feet tall at the moment) and a few smaller ones.

Could I reasonably expect a 15-20% or higher increased yield running the greenhouse at 1500 PPM?

Thanks for reading

eh ....
In theory yes. But it is a lot of money to run one in that size ... I am thinking of running co2 in my room and I am looking at spending about 60 a month on co2 (bottles) I know your not running bottles but .. There are risks and other things with those things. Fire. Make sure your room is tight, and secure. Co2 will just float away. even more if your running blowers to the out side. Unless you time them to turn off here and there with a controller w/ co2 monitoring. Its enough to do for me in a smaller room, let alone a green house.

im going to go with no...$500 plus time and gas...
i think the money would be better for dehumidifiers
imo you should only think about co2 when everything else in dialed in...

Right now the greenhouse is say 85% sealed, I have a few openings and a 6" fan bringing some more air in. It's not that hot anymore where I'm at so if I added Co2 I would be able to fully seal so it's not like they Co2 will be able to just float away.

I will read up on dehumidifiers, I've never used them before so I have no clue what size I should use.