Heating or A/C Loss from Vent Fan?

[echdk3]

Hello!
This is my first post here. I’ve frequented this site for a long time and have learned tons, so I’m very excited that I just got my medical card and my cultivator license from the state! I’m still designing my grow room layout and my biggest worry is what will happen to my heating or air conditioning bills when I have this high power fan exhausting air outside my house 24/7? It seems like having the ventilation fan blasting that much air outside the house would require my heater or a/c to just be on all the time and that the bills would be outrageous and maybe even prevent the house from staying comfortable. What do you experienced growers think, is this a problem? Thank you very much and I look forward to engaging with you guys as I learn my way around the tent.

[buds73]

I don't know much about AC as im in UK and AC in the home is not the norm however have you considered maybe using a separate extraction fan just for that grow room?

[Xena]

Since you’re legal you don’t have to worry about smells getting you busted. I’m a noob but I have no exhaust at all and I haven’t had a heat problem at all. I live in the Midwest and it’s hot and humid in the summer and cold in the winter, winter I won’t mind some heat added but this summer has been hot and my tent is in the corner of my bedroom and I have no problem with my ac keeping up with my led lights.

[echdk3]

Hey guys thank you both. buds73 can you possibly explain what you mean? My plan is pretty standard, a variable speed vent fan capable of 710 CFM drawing air through a carbon filter in a 4x4 tent then exhausted out of the house, with several ducting turns and roughly 50 feet of distance, hence the extra power on the fan. I’m just worried I’m wasting tons of freshly heated air from my furnace, or air conditioning in the summer. I don’t plan on running it at the full 710 CFM by the way, I just want the extra power available on hand because of the significant distance I need to travel and the many turns in the duct layout.

[Xena]

What kind of light are you using? The led in my 3x3 doesn’t get that hot. I guess what I’m saying is, why do you have to vent clear to the outside? You’re running through a carbon filter, why not just vent out into the room?

[dphipps1020]

If he vents directly into the same room he will be heating up the entire room and possibly the house. That will cause the A/C to work harder. Heating shouldn't be an issue in the winter if you're running hot lights. I have a portable A/C in my big tent that exhausts straight out the window because it will get too hot in my house otherwise. I may take the exhaust out of the window when it gets colder so it can help heat up my house. Or I may just take it out all together, we'll see.

[echdk3]

Ah, I was just worried about the smell. I don’t want even mild odors in the rest of the house. This will be in the basement and I don’t want to draw attention to it from the rest of the house. Do you guys think I need to vent to the outside to achieve this? If I vent right back into the room, will the smell be noticeable in the rest of the house? I’ll mention that it is an original Gorilla tent, which is quite thick.

[dphipps1020]

If you're worried about the smell in the house, you'll want a carbon filter. Especially if you're planning to vent into the room your tent is in. My portable A/C blows straight out the window and smells overpowering sometimes. I'm just glad it's legal here or I'd be having some trouble I'm sure. My A/C doesn't have a filter so it just blows the smell straight out.

[echdk3]

Thanks for your replies! I will be using a Black Dog PhytoMAX-2 600 which doesn’t get very hot at all. I will definitely be using a carbon filter either way (please see my earlier post that lists my current plans in detail). I guess now I’ve got two total questions:

1) If I vent right back into the same room, will the smell be noticeable in the rest of the house?

2) If I do end up having to vent outside the house to avoid the smell, will this be a major draw on the furnace and air conditioner?

[golfnrl]

echdk3 welcome! My 6" exhaust fan runs 24/7. My 3x3 grow tent is inside a spare room that is about 13'x13'. The fan draws fresh air through the carbon filter and vents back into the grow room. The grow room A/C is on its own zone. Had no idea I would be growing ten years ago when the A/C was installed. I digress, We don't notice any cannabis odors anywhere else in the house. I kinda like the smell, she doesn't and let me know about it. Hence the fan and filter. The preference is to vent the exhaust outdoors. Not every set up allows that. Mine doesn't...hasn't been a problem. I'm no HVAC expert but the minimal amount of air your 6" fan will move should not have an impact on your power bill. My concern would be the length of your duct run and the size of fan required. I ran across this link. Maybe it will help. https://whatforme.com/grow-room-fan-size-calculator

[sgiacomo]

I vent my tent into the attic 24x7 through filter. It doesn’t move enough air to change ambient room temp in my experience. It does alleviate smell. I wouldn’t recommend venting into the same room, need that fresh air coming in!

[dphipps1020]

I vent straight into my rooms, other than the A/C in the one tent. I have hot lights so I have to keep the window open in the bedroom for cooler air. Now that it's almost winter time I can get rid of the A/C soon too and use the lights to heat my house.

[MrMagic]

Just follow the kiss rule. I'm in a 1000sq/ft apartment with a 3x3 tent. Put the vent fan inside ur tent and vent to the room, with a carbon filter on the intake side of the fan. You will not notice the at all. You cant smell a thing in my apartment. That being said carbon can only hold so much smell before it will no longer work so you'll have to replace the filter every few grows. I'd be more concerned how your going to deal with odors during the drying stage. This is the smelliest part of the grow.
if your using led lights your temp should be a few degrees over ambient this is not enough to affect a room's temp. Consider this. most of us dont worry temp fluctuations when we leave bathroom and kitchen fans on for extended periods. Eg smoked out kitchens and smelly bathroom users. Just think of it as a bathroom fan. I would be concerned with the length of ducting needed to get to the outside. 50' is pretty far for a 6" fan I'd be concerned of prematurely burning up the motor..
if ur tent is in the basement I'd would say with great confidence that if your carbon filter is replaced every X amount of grows you can vent directly into the room without issue. I have zero issues is thi tiny 1000 sq/ft appartment.
hope this help

[echdk3]

I really appreciate everyone’s advice here, thanks! Maybe I mistyped earlier, but I’m going to use an 8” fan (not 6”) capable of 710 CFM, just because I want the extra power available if I need it (the speed is fully adjustable so I can dial it down if I want to) since I have so much distance to the nearest outside window.

I did look up a typical bathroom vent fan and they seem to typically be around 50 - 75 CFM, so not that much.

Does anyone else have an opinion on this? Vent to same room okay for avoiding all odors with my set up (4x4 gorilla tent and 710 CFM fan through carbon filter), or do I still probably need to vent to the outside instead? And if outside is needed, anyone think this will have a significant negative effect on how often my furnace or central A/C is on? I’ll note that this is a standard sized 2 story house plus basement, which is where the grow will be.

You guys are awesome, thanks a lot!