Can I vent my grow room out my furnace exhaust

My Grow area is right next to my furnace venting going out to the roof. Can I use only a wye fitting to tap in, or do I need to put a backdraft damper in to prevent exhaust leakage back into the grow room when the fan is off. I am on a shoe string budget and am trying to save $$. I would make it a closed system and cirrculate back into the veg room but in order to cool the air back down it will cost more in materials then this option

This could be a deathtrap if the carbon monoxide from your furnace re-enters your house. There may be a safe way to do it, but I don't know what it is.

you can do it. But i wouldfnt recomend it. it will affect the draft of your furnace, and therefor lower efficiency of your furnace.

I was afraid of this. I suppose I'll check out diy carbon filters and vent under the stairs. Any other suggetions or advise dealing with original thread would be helpful.

Venting into your attic would work too.

I do that....but i dont use the furnace in the chimney anymore....if you never turn the extraction fan off...then it will work.....but you will need another hole in the chimney.....vneting into your house is a bad idea if the grow has any size to it......also...you need a filter regardless.....I was firing out the chimney for awhile....with no worries...during the last month of flowering.....I began catching whiffs in my yard and even acrosss the street....and this is during a wet windy west coast winter....get a filter and hook it up....think about how you can smell people fireplaces when you walk down the street.....smells are funny. good luck.

So keeping the fan on, keeps the air flow going, preventing dangerous exhaust from the furnace from leaking back into the grow room duct. Am I correct in my choice of using a wye fitting to tap into furnace duct because it acts as a sweep directing the air up and out?

If you blow too much room exhaust, it can cause backpressure in the furnace forcing CO.
Not worth the risk.
You can however vent into the stack of your plumbing system without danger.
But K is right, smells do travel so it's always best to filter first before you blow it out.

Yeah screwing up the exhaust of the furnace has been my biggest concern. I live in townhouse apt. so sorta limited to how far I can remodel. I am a red card holder so keeping the rooms cool is more importent then smell right now. Might see if keeping cool tube on dedicated duct pulling from outside flower room venting into laundry room. I have a 400w hps 6" cool tube

Just checked the basement area and this place is cheap, my only access to the outside is the furnace vent. So any advise on a safe way to use the furnace or suggestions on threads to doing a closed system I suppose. Thanx

Stopped by homers and got 6" to 4" fitting for the cool tube. 25' of flex duct and priced the wye, only 10.00. Noticed a back draft damper for a dryer for 6.oo and thought if it was back right after my fan, at the end of the vent run before the last 2.5 ft. of duct that taps into furnace exhaust via a wye fitting. It would prevent exhaust from leaking back into the grow room. My flower room is 2.5x5.5x7 lit by a 400w hps 6"cool tube and built next to basement stair case. At least it will be/better be cuz my babies getting big. I'll take some pics of exhaust area to give you all a better idea of what I'm dealing with

well here is a pic of the furnace exhaust as it is now. Any ideas comments anything about my plan of tapping in

ballemason said:

Any ideas comments anything about my plan of tapping in

Click to expand...

Cut it and throw in a 45deg wyes joint, then tape it back up =)

http://americanhvacparts.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=TEE6X6X6&Category_Code=duct-teewyes

Connect it to the furnaces INPUT not the exhaust. Then when furnace is off the 'heat' will go through the entire house, not just out a single vent.

researchkitty said:

Connect it to the furnaces INPUT not the exhaust. Then when furnace is off the 'heat' will go through the entire house, not just out a single vent.

Click to expand...

This will cause the house to be warmer in the summer, and can allow any odor particles not absorbed by a carbon filter on the exhaust to build up indoors. And it's sometimes harder to tap into furnace input than exhaust, since most furnaces just draw air from indoors through a large vent on it's main body.

It may simply not be an option for some people, but if you can get by / tolerate said issues above, it's not necessarily a bad idea.

Also, pardon my hastiness before, but is the round duct the exhaust, or that large rectangular ductwork behind it?

The round duct is the exhaust and connects to a 8-10 inch main vent leading to the roof behind the drywall. The rectangular ducting is the cold air return and the main heating duct run. My original plan was to use the 45 deg. wye just before the elbo that connects to 8-10 inch. main vent in the wall. I was considering placing a backdraft damper in right after my fan thats pulling air from the grow area to prevent furnace exhaust from creeping in. I might see about tapping into the heating duct that runs to the top floor. I would just have to fix the hole before the lease is up but it might be safer. Darn it I can't make up my mind, and the drywall is going up today, not a week to soon cuz I have 5 babies ready and only room for 4 in the veg room. I'll start a journal here soon to show room setup and my girls.

Well without enough expert advise I have choosen to exhaust my light and flower room into the laundry area with a great diy carbon filter design I found on Grasscity. My damn camera eats batteries so I am behind on getting my journal started, but I have three ladies into flower and will be collecting pollen from my only male so I can play mad doctor and get some more seed stock for FREE

That sounds a lot better. If you try to blow air into the furnace exhaust there's a chance you'd reverse the flow in the exhaust and force it out the furnace body, potentially causing CO to build up in the furnace area

Heres my currently passive system, Cool air in from down low. Hot air up and out. CoolTube as-is, is closed. The room itself has a cold air intake (not shown), and a 4" T above the HPS for heat exaust. When my $35.00 total/4" inline/240cfm fan arrives I will connect the light exhaust to the room exhaust. Putting the fan at the end pulling air from both and pushing it out a DIY carrbon fillter I have yet to make.