Harmful?

I was wondering if anyone in here may know enough info to answer this question. My grow room is really close to my PROPANE water heater. I could easly tap into the ventalation to pull the CO2 created by the spent gas.
Is this safe?
Thanks in advance......

I would say don’t do it but people on here do. The co2 would be rather irregular coming from a water heater that runs off and on. Also for the health of the household I wouldn’t do it. If you try it just have a carbon monoxide monitor in there. Here is a post I created about co2. I have been using yeast and sugar.
https://www.rollitup.org/indoor-growing/34862-best-method-co2.html

I should have mentioned the grow room is in the garage. Totally sealed. Fresh air brought in through ducking and dumped out a window box. I like the carbon monoxcide detector idea. Anyone else have two cents they could throw me?
Thanks alot.......S
Here is a link to some info I post about using yeast and sugar. https://www.rollitup.org/indoor-growing/18241-diy-co2.html

yea if no one lives in there and u vent it for a min or so b4 u go in it will be fine and switch it during lights out

I wouldn't do it. There's no way to control ppm levels and you could end up with more C02 and water vapor, (humidity) than will be good for the plants, not too mention Carbon monoxide. Carbon monoxide detectors should not be relied on to detect a problem that will eventually happen, as opposed to detecting a problem that may happen. Also single walled water heater vents can reach 500 degrees on the outside. Can you say fire hazard?