Dumping grow room heat into your heating system vents?

[Camaro1691]

Am getting ready to fire my room back up before too long and am debating the thought of hooking my exhaust into the vent in the floor of the bedroom the grow room will be in. There will obviously be a charcoal filter near the ceiling of the room to draw the most heat, and possibly a one way flapper after my fan before it goes to the floor vent. Has anyone tried this? Was there any negative impact to or from the furnace? I’d like to utilize the heat from the grow room to help offset my heating bill during the winter for the higher cooling costs during the summer

 

[fanleaf]

Charcoal filter or not. This will smell up the house in flower. Try it though lol, let us know how it does.

 

[RuleAndrews]

That's basically what I am doing now....and because its winter, the house is very dry so the little bit of humidity that comes out of it wont hurt...I wouldn't do this in summer though.
I'm three week into flower and the tent absolutely stinks, but I cant smell anything in the house.

 

[Camaro1691]

Charcoal filter or not. This will smell up the house in flower. Try it though lol, let us know how it does.

I’ve never had an issue with smell in the house before, had the exhaust dumping right into the basement with charcoal filter in the room, I always oversize my filter and fan from what’s actually needed I don’t play with not enough filtration, low odor is a big thing to me but nothing I expect issues from venting the air thru the heating duct more or less if it will effect the furnace seeing as there’s a heat sensor off the firebox to tell the fan when to cool the firebox/blow air into the house, I’m not sure if this will be an issue is my main point, something I’m willing to try just didn’t know if there was someone who had already done it and how it worked for them

 

[fanleaf]

I’ve never had an issue with smell in the house before, had the exhaust dumping right into the basement with charcoal filter in the room, I always oversize my filter and fan from what’s actually needed I don’t play with not enough filtration, low odor is a big thing to me but nothing I expect issues from venting the air thru the heating duct more or less if it will effect the furnace seeing as there’s a heat sensor off the firebox to tell the fan when to cool the firebox/blow air into the house, I’m not sure if this will be an issue is my main point, something I’m willing to try just didn’t know if there was someone who had already done it and how it worked for them

That's awesome. I figured it would still smell. I grew so.e super stinky ak47 a few years ago and even with my new filter it still stank outside where it was exhausted.

 

[Jackalope]

I agree. While it is a good thought. There is to much that could go wrong. The filters will clean the air enough so that is not the problem. What could happen to your heater or your plants if something goes wrong is to big of a risk. I would worry about the heater coming on while the tent fans were running. The right air combinasion could send hot air to your grow even with a flapper valve.

 

[Chris Scorpio]

I've always done it
Pump it into my air return in my room

As long as the filter is working, no smell ever comes out

 

[SmokeLake]

Im just venting into the room my tents in but my furnace is right there. The only way venting to hvac would make sense to me would be by venting tent or room into the cold air return and depending on distance from the actual furnace your fan would push the air into cold air return the warm exaust air would likely rise from the nearest cold air return vent nearby or possibly flow thru furnace filter and on into vent system. Personally id be hesitant venting moist air into the return it could provide a home for mold or mildew to grow.

 

[RuleAndrews]

I'm struggling with humidity issues as it is, so its not like much moisture is being vented out of the tent.

 

[TurboBucket]

I run two 4*4 tents into my return duct with my Central blower running constantly. With the heat from the tents and one electric heater upstairs the gas furnace hasn't fired yet this year. I had to add louvers to the door for the room though. The hyperfan pulls more air than the single 6in supply duct can provide.

If your going to tap into a supply duct a backdraft damper is almost a must. A strong enough fan/filter combo could create enough static pressure to overpower the furnace blower but if your fan cycles at all you could end up with some very warm tents.
Keep in mind for all the old air your trying to take out of a space there needs to be a way for just as much new air to get in there.

 

[Camaro1691]

I typically run my exhaust 24/7 for filtration if smell more soo than removing heat but living in a mobile home now, it gets rather warm in the room the tent is in if I just vent it to the room, in a basement I’d just vent it to the basement and didn’t have issues, soo I don’t think heat coming into the room will be an issue, and it is on the furthest end of the house from the furnace, with 4 other vents before the furnace soo as I think about it more and more I think it will just push air into these rooms rather than actually working it’s way to the furnace, as for humidity, my house is dry as hell like you wake up with your throat dry it’s that dry, soo I think a little moisture will help out rather than cause issues, guess there’s only one real way to know, gunna have to try it on a case by case basis I guess. And for the other comment of air going into the room, I typically run a fresh air fan and filter that put 2/3 as much air into the room as than the exhaust pulls out as to ensure it still sucks the odor out

 

[Camaro1691]

Another thing I forgot to bring up is being in a mobile home the furnace pulls it’s own air from outside not from in the house like a traditional furnace would. This should be of some benefit as to not back feed the furnace per say. I’m gunna have to find a pot friendly HVAC guy to run these concerns by and see their thoughts on the subject as it seems from the few responses soo far to be mixed opinions on this. But before talking to one I’m coming to the conclusion that this can be done without effecting the furnace too much or at all, as I’ll simply be moving air from my grow room to the 4 vents before the furnace, it’s a long enough duct that I don’t think there will be any back pressure issues, my exhaust is only around 650 cfm and is ample for my room, I’m led not HPS soo that’s a plus as far as heat, I don’t know how many CFM my furnace fan puts out but I know it could be stronger as the furthest vent away from it puts out such minimal air it’s questionable any comes out that vent at all but indeed it does because if you close that vent that room gets chilly on cold nights... the other thought I had was going under the house and unhooking the duct going into the grow room and blocking it off coming from
the furnace and using the vent in the room to push my heat under the trailer to help prevent pipes from freezing and keep the floor in the rest of the home warmer cause it can get a little cold if walking barefoot when it’s around 0 outside

 

[Bilbobudkin420]

I agree. While it is a good thought. There is to much that could go wrong. The filters will clean the air enough so that is not the problem. What could happen to your heater or your plants if something goes wrong is to big of a risk. I would worry about the heater coming on while the tent fans were running. The right air combinasion could send hot air to your grow even with a flapper valve.

Yer ive heard horror storys of the pressure going back so its pushing heating exhaust fumes back into your grow area (in your case your bedroom) depending what system ya using this could be carbon monoxide. Personally i wouldnt reccomend it.

 

[TurboBucket]

I am a pot friendly HVACR tech lol. Your mobile home furnace likely uses what's referred to as a wild return, it pulls air in through the closet door as opposed to a dedicated return duct. The air it pulls in from outside would only be used for the burners.

Yer ive heard horror storys of the pressure going back so its pushing heating exhaust fumes back into your grow area (in your case your bedroom) depending what system ya using this could be carbon monoxide. Personally i wouldnt reccomend it.

This would only happen if you were to tap into the venting for the combustion cycle which is definitely not recommended and very difficult. It's also impossible on high efficiency units as they only use 3inc PVC as vents.

don’t know how many CFM my furnace fan puts out

Depending on the draft type and burner size it's likely in the 800-1200 cfm range at most. Residential Ducted systems are generally designed with a low static pressure (.1-.15"water column) to keep noise and wind chill effects down.

If you put a blower on the end of your duct at register #4 for instance you essentially have two fans fighting one another. The low pressure high volume fan in the furnace will supply air to runs 1-2 and pull air back from them, the tent fan will pull air from number 3 and push it back into #4 and out #3 you could end up with two zones within your home not changing air between them. In a trailer house that's pretty unlikely as long as the doors to those rooms are open. Air movement is all about pressure differential air moves from high pressure to low pressure.

the other thought I had was going under the house and unhooking the duct going into the grow room and blocking it off coming from
the furnace and using the vent in the room to push my heat under the trailer to help prevent pipes from freezing and keep the floor in the rest of the home warmer

Any air you push from the house to the outside has to come into the house first. It will suck air in through windows and doors, you want a positively pressurized home so your not constantly heating/cooling new air from outside. it also creates the possibility for mold and mildew though unlikely under a trailer depending on the skirting. I would recommend against it.

Any easy solution would be a through wall fan, push the air from that room back into the rest of the house to be accumulated by the wild return and pulled back in through the duct and under the door. If the door never needs to be closed and you use a back draft damper you should be ok to vent into the supply duct but it wouldn't be my first choice.

I tried to keep that somewhat coherent please feel free to ask for any clarification.

 

[Camaro1691]

Much appreciated for the response, I do understand what your saying for the most part. And to my understanding it’s being recommended not to do lol, what needs to happen essentially is I need to stick it out in this home for 5 years before I can sell it to buy a better home, one with a basement, basement is a must for me for my meds, debating just digging out under this home and adding a partial one for my room.

 

[Jackalope]

Nice to have Tech support show up. Pretty sure I would listen to the guy. He has the work experience to know what is being dealt with.

 

[Camaro1691]

Yup I’m holding off on the idea for now... I’ll just build a box for the window in the room and will take cold in from the bottom of the window and push it into the bottom of the grow room and the exhaust will go out the top of the window. This will be more than enough to dump the heat and keep the room cool, was just hoping to use some of the heat in the home without adding a bunch of duct from the exhaust

 

[TurboBucket]

Yup I’m holding off on the idea for now... I’ll just build a box for the window in the room and will take cold in from the bottom of the window and push it into the bottom of the grow room and the exhaust will go out the top of the window. This will be more than enough to dump the heat and keep the room cool, was just hoping to use some of the heat in the home without adding a bunch of duct from the exhaust

Good idea. Be careful though you could freeze out your plants if the out door temps are too low. Can you cut a transfer vent in the interior wall or even just the door? Pulling from outside and dumping into the rest of the house would be great dumping it into that room with a way for it to get out of there would be good too. A zone damper wired in with the fan controller would be slick, no outside air can get in unless the fan is running

 

[zigzagburning]

I do use this method. I have the out take of my tent vented to my intake register to the furnace. I have a 6" carbon filter inside tent hooked to out take. I went to the hardware store got a register and fit it side the other register in the floor with out take hose attached to it. It only goes as far as the furnace and comes out where your fan is ,on the furnace. good for winter months. It does not get cold or to hot . I plunged the out take register in the room with tent so no heat is blown in. Also when lights are off you don't need any fans on . When furnace is heating your home it will suck the air from your out take and circulate your room. I leave a little crack in widow for fresh air in the room the tent is in. It works pretty good

 

[Camaro1691]

I do use this method. I have the out take of my tent vented to my intake register to the furnace. I have a 6" carbon filter inside tent hooked to out take. I went to the hardware store got a register and fit it side the other register in the floor with out take hose attached to it. It only goes as far as the furnace and comes out where your fan is ,on the furnace. good for winter months. It does not get cold or to hot . I plunged the out take register in the room with tent so no heat is blown in. Also when lights are off you don't need any fans on . When furnace is heating your home it will suck the air from your out take and circulate your room. I leave a little crack in widow for fresh air in the room the tent is in. It works pretty good

Did you notice much of a difference in your heating costs?