Venting Grow Tent Outside in Winter

[Ganja Goose]

This is the one topic that I have had trouble finding information on this past year of learning. The majority of the threads related to venting tent exhaust end up talking about venting into attics and cutting holes in walls, etc. I don't want to go down that path if I don't have to. I have zero risk tolerance when it comes to possible damage to the house.

I have recently moved my 4x4 tent downstairs and thus made the decision to vent the exhaust outside. I had considered venting into another room, but I was paranoid about the possible smell and also had concerns about the humidity and possible moisture problems down the road. I recognize you can combat these concerns with additional equipment in the room itself, but I thought my plan to vent outside was a solid one.

I run a 6" AC Infinity fan with the aforementioned scrubber and then there is about a 4 foot run of ducting to the window. I put a piece of 1" styrofoam insulation in the window space and cut a 4" hole through it. The 6" ducting goes thru a reducer to a 4" and then thru the window via an aluminum pipe that extends out into the window well. I reduced the exhaust to a 4" thinking it would reduce possible cold backdraft. My tent exhaust is about 26.5C/80F and the RH in the tent is about 60%.

All of that said, its around -2C/28F outside and I see that the humidity drops out of the exhaust part way down the exhaust pipe and its starting to freeze. I know realize that this is going to probably cause possible issues a couple of months from now, if not weeks.

Have any of you ever experienced this problem and how did you combat it? I know someone is going to say to cut some holes in the walls or vent into the attic lol

Any insight you have would be greatly appreciated. Sorry about the long-winded question. Blame the Blue Dream!

GG

 

[Rexer]

Im venting outside and havent experienced any issues (yet). But I totally agree, vent outside to avoid damaging the house is smart. No clue if it makes any difference, but I've insulated my exhaust vent (helps keep heat bleeding off in summer).

 

[nivek]

confused here,,

where is the freezing occurring,,?

i have the near identical setup in my tent indoors, minus the reducer,,

there is no way, with the fan running, that any temps in that pipe could be below freezing,, the fan is blowing warm air out that pipe

please explain friend

 

[Ganja Goose]

hey @nivek,

At the end of the exhaust pipe in the window well. It was only a small amount but I assumed it would only get worse as the outside temps get lower. Maybe I assumed wrong?

Do you exhaust thru 6" ducting as well?

GG

 

[Joe Brewster]

Just remember to add an air make up , if your house is new & energy efficient pushing large volumes of air out side with out one, you will pull carbon monoxide down your furnace chimney

 

[Ganja Goose]

Im venting outside and havent experienced any issues (yet). But I totally agree, vent outside to avoid damaging the house is smart. No clue if it makes any difference, but I've insulated my exhaust vent (helps keep heat bleeding off in summer).

Hey @Rexer

Thanks for the response. Do you experience below freezing temps where you are at? and how long of an exhaust pipe do you have outside?

GG

 

[Ganja Goose]

@Brewsterman I've never heard that before. How exactly does an air make up work?

GG

 

[Joe Brewster]

@Brewsterman I've never heard that before. How exactly does an air make up work?

GG

draws outside air in & conditions it before entering building
Had to have it in the autobody shop when we turned on paint booth fan
I see they have them for kitchen vent fans, for these high efficient homes now .All part of the HVAC system in homes today

 

[Rexer]

Hey @Rexer

Thanks for the response. Do you experience below freezing temps where you are at? and how long of an exhaust pipe do you have outside?

GG

I can hear the snow hitting my window as I type....

My exhaust is roughly 8 feet? Length as yours in the pic. I have a few more bends in mine and got an 8 inch reduced to 4inch (just for the extra tourqe). It's cools my 400W MH/HPS hood.

 

[nivek]

I actually do reduce my exhaust,, i do. I have a six inch fan reduced to four inch but my reducer is in my room, not outside the room like yours. But still the same

I can not see frost being a problem in your system friend

AAnd yes, as @Brewsterman mentioned, the air venting outside needs to be replaced in the house. My air intake is a leaky outdoor door seal

Kfrost karma sent

 

[Buds Buddy]

Sounds the same as when you start a car in the cold. Hot air out the tail pipe meeting cold air outside creating steam & moisture drops.

 

[Ganja Goose]

I actually do reduce my exhaust,, i do. I have a six inch fan reduced to four inch but my reducer is in my room, not outside the room like yours. But still the same

I can not see frost being a problem in your system friend

AAnd yes, as @Brewsterman mentioned, the air venting outside needs to be replaced in the house. My air intake is a leaky outdoor door seal

Kfrost karma sent

Ya I have a few leaky doors and windows myself. I put a couple of CO detectors downstairs just in case. I have nothing but bad luck so I better take some precautions of some type.

The frost karma is going to have to stand in line with all the other karma coming my way lol

GG

 

[Ganja Goose]

@Rexer and @nivek

Do either of you use a check valve of some sort or cover the end of the exhaust with anything? I had originally installed a little 4" screen over the end of my exhaust but in my fear of things freezing off I had removed it. I think I'm on board with the fact that this might not freeze up but I'm looking for other options out there

GG

 

[Rexer]

Yes I do, not sure if it's needed though. I have covers on the outside for esthetics and it has a bug screen (there's one for intake and another for exhaust). Then mainly to prevent smell leaks during a power outage I have backdraft dampeners.

 

[Emilya Green]

I simply made a 3/4" thick wooden insert big enough to hold a vent cover and a 6" diameter vent, and fit it to put in the grooves in the window sill, allowing me to close the window down onto it. Even though my Pella windows seal fairly well at the top in this position, I put some extra foam insulation up top in the gap to help seal out the winter.

 

[BeanTownFan420]

 

[Buds Buddy]

If you're that concerned with the freezing maybe wrap it with a seedling heat mat.

 

[Ganja Goose]

I simply made a 3/4" thick wooden insert big enough to hold a vent cover and a 6" diameter vent, and fit it to put in the grooves in the window sill, allowing me to close the window down onto it. Even though my Pella windows seal fairly well at the top in this position, I put some extra foam insulation up top in the gap to help seal out the winter.

Me too @Emilya. I used a combination of wood and styrofoam and filled the gaps with foam insulation just like you did. Seems to keep the cold air out so far!! I'm really surprised someone hasn't patented a grower version of the window spacer yet.

GG

 

[Buds Buddy]

Me too @Emilya. I used a combination of wood and styrofoam and filled the gaps with foam insulation just like you did. Seems to keep the cold air out so far!! I'm really surprised someone hasn't patented a grower version of the window spacer yet.

GG

They sort of have. You can buy Window Kits for Portable AC's.

 

[Ganja Goose]

@Buds Buddy ya the "sort of" was one of my problems. They looked wafer thin and I didn't think it was robust enough to deal with the -20F winter cold so I ended up creating an insulated version. Just need a little more robust version of the AC window insert

GG