hot water heater for co2

i have been doing alot of reading on the many ways of using co2 from diy's systems to burner and generators and such. one thing i have read is that you need to get to 1500ppm for it to be affective. first i am wondering wouldnt any amount of extra co2 be benifical to your grow. weather it be just an extra 100ppm.s? also using the exhaust from the hot water heater would be bringing in extra unwanted heat and i am wondering if anyone would have any ideas of how to cool the air with out plugging in any extra equipment? my electric bill is already high enough and no need to raise any more running an air condidtionar. the heater only sits a total of 8 feet away from my grow area and that is even running the duct up and over. i was thinking of some kind of coiling of the duct to slow it down to cool it but not sure if it would still be as affective waiting for it to enter the room. so if you could figure out a way for me to add to the room with out any other electrical usage would be great and i thank you in advance. lefty

I dont know much about co2 but i do know that all that heat cant be good and the trouble of cooling it would be to much. I hate to shoot this idea down cause its so cost effective but without running an air condition its just not smart.

i have been racking my brain and i think i have an idea that just might work if you could try and follow along and tell me if it seems doable. lets say i bring the water heat in at the highest point in my room. we know hot air rises and co2 is heavier than air. so if i place an exhaust fan on the oppisite side of the room at the same hieght i would be allowing the co2 to cool enough to seperate from the hot air and settle to the floor. drawing out the hotter air faster than it comes in then i could in theroy keep the temps in check. and using a few personal fans i already run and placing them on the floor i would stop the co2 from settling on the floor. does this make sense or even seem worth doing? i have a carbon minoxide monitor in the basement just cause my in-law if the retired fire cheif and wanted to make sure we are all safe with the silent killer so i would know if it was the wrong gas and i am not killing my family.
honestly from everything i have a co2 burner is nothing more than natural gas/propane so i would be doing the samething. so hopefully you could follow along and plese let me knjow if it is worth even attemping

Sounds like a damn good plan. And yea I was going to say get some sort of tester just incase cause we don't know every gas coming out of that heater. I would say monitor it close until you feel pretty sure that its safe. But other than that. Good idea. Let me know how this works out.

i have been racking my brain. and i am glad that you agree with me. and think it would work. i just feel if i am intake on oneside and out take on the other than the co2 might cool off enough to make it worth while. i feel any co2 would be an added bonus maybe i dont get to the 1500ppm's they say is needed but a little extra wouldnt hurt.....we shall see as that will be my saturday project....i will let you know how it works out

Hows it been going so far. Just making sure you havent had any problems with the silent killer. Dont wanna lose a fellow stoner.

heres an idea
get a heat exchanger and run the incoming water to the water heater through it. then duct the exhaust through the heat exchanger.
then for the most part whenever the hot water heater is running there is probably cool water running into it so then it would hit the heat exchanger first before going into the water heater. u get what im sayin

heres a lil diagram i made up real quick to help explain what im saying.

i know it wont cool all the exaust but it will help a little

A few things:

1. "wouldnt any extra co2 be beneficial to the grow?" Maybe. Would more protein be good for your body? Maybe, if the conditions are right. If you aren't under the optimal conditions to utilize extra protein then it will have no extra benefit. Eating 8 protein shakes a day will not make you buff. You have to work out also. Same with the plants. CO2 is most likely not your limiting factor in growth, so more does not automatically translate to more growth.

2. every hot water heater ive seen has a passive venting system. its just an open pipe sitting above the exhaust hole. The pipe will be under a slight negative pressure from the stack effect. If you pipe it to your grow room it won't be under the negative pressure because the end of the pipe is no longer in the chimney, meaning you will have to install a fan.

3. the co2 wont be cool and wont sink. It will be hot because it was generated in a combustion process.

4. If you are pumping air in via the hwh exhaust though I dont think the co2 will "settle" like you think. you will have turbulance and changing pressures in your room. it will be thoroughly mixed. especially if you also have an exhaust fan.

I don't think it's worth the trouble. I would advise against.