Condensation makes me wet! help me rethink my ventilation.

[thcrefugee]

Hello all,
Thanks for reading.

I just moved into a new space and was very excited to finally run my lights on their own seperate "dedicated" ventilation line. (window-hood-window).
My problem now, is its too cold outside and I'm getting condensation on my intake fan where the duct ends, and its dripping into the tent.

I was hoping to run the lights separate and use a second fan to exhaust tent air into out the window too, thru a carbon scrubber of course. I just wanted to minimize the temps, and the airflow through the scrubber, for life expectancy.

1-2kw, winter, dry climate. tent in spare bedroom.

Got any ideas that might have worked for you?

 

[eyes]

If you have enough cfm for the 2 1000s, why not run inside house air? You will always have that problem when sucking cold air into a hot hood. same goes for a metal vent fan with cold air and warm atmosphere. You can wrap the fan and the hoods to cut down on the condensation. This would be one way if you insist on sucking cold air through a warm hood and metal fan. Using house air from an adjacent room is a way to stabalize temps through the metal fan and hoods without wrapping them.

 

[thcrefugee]

If you have enough cfm for the 2 1000s, why not run inside house air? You will always have that problem when sucking cold air into a hot hood. same goes for a metal vent fan with cold air and warm atmosphere. You can wrap the fan and the hoods to cut down on the condensation. This would be one way if you insist on sucking cold air through a warm hood and metal fan. Using house air from an adjacent room is a way to stabalize temps through the metal fan and hoods without wrapping them.

Thanks for the quick response, eyes!
I thought about that as well, running room air through the hood intake,
I just wanted to avoid sucking all my warm house air out of the house. And, its not quite cold enough to just recirc the warm hood air in the house for heat just yet.
I figured isolating the hood ventilation, would: keep the tent environment more stable with temp and humidity, and allow me to exhaust less house air out of the house. And also keep the constant air flow through the filter down to extend its life.

I was hoping someone had some neat tips. It seems like the ideal solution is some mixture of set-up where the room air can buffer the cold outside air.


For clarity,
Two windows, spare room, with a tent in it. I have multiple fans, a can66 filter, and one t-stat, as well as a cycle timer, for controls.

I was thinking to just cycle time the hood air to avoid major condensation, and just exhaust the tent air on the t-stat.
I hope to soon purchase a master timer, with built in t-stat, so i will have two thermostats to play with. but funds are low right now.

 

[eyes]

I wouldnt cycle time the hood air. You risk popping bulbs to heat build up in the hood itself. I would use the house air since you said its not cold yet. So you wouldnt be sucking heat out since your not heating the house. Take that hot air and exit it into an attic which will find its way out the gable vents or soffitt vents. WHEN it gets cold, use the house air and light heat to heat the house.Suck form one end and dump in the other. With 2 1000s the house will act as enough ballast to balance that heat load. You are right with by venting the hood heat isolating it from the tent, therfore keeping the temps and humidity more stable in the tent. I really wouldnt worry bout sucking out all the heat out of the house. So many factors play into that. Age of the house how tight it is and such.

Use the humidy stat to vent the tent air through the filter. control the condensation in that tent. You should be using the cool/ fresh air from outside to vent your tent unless you have co2 supplementation. either way, humidity will rise and it will have to be exhausted.

 

[thcrefugee]

Thanks again for the help, and Great Advice on the bulbs blowing.
A few things, I won't vent into attic b/c of potential moisture/mold. I have two windows and a door in the room, I need to use these existing openings. Im happy to leave the door open and point the hood heat out into the house. The landlords dont want to see too much modification to walls.
My concern is that if I pull room air through the lights, and blow it into the house, is it going to pull stinky tent/ room air and blow it into the house or outside.
The tent air obviously gets exausted from the carbon filter hanging in the tent. I can blow that inside the house, or outside. Its warm and clean of smell.

My goals are:
Conserve heat, and/ or heat the room and house.
Eliminate ALL smell outside, and ALMOST all inside the house, and MOST inside the room.
Run less air through the carbon filter.

 

[queequeg152]

the fan casing is sweating? or are you talking about the grills or....?

simplist thing to do is simply wrap the cold surfaces with fiberglass or mineral wool duct wrap. fiberglass will be far easier to find.

id suggest getting the stuff at a real hvac supply house... the home depot products are fairly shitty. try to get some R8, 2" wrap with a reinforced wrap material. most of the time the wrap is a foil faced fabric material. its very resiliant.

get an outward clinching staple gun and a can of super 77 spray adhesive. you spray a strip of ahesive on the fan and wrap the insulation being sure not to compress it.
cut away a 1 or 2" strip of insulation exposing just the fabric. overlap this exposed strip and staple it down onto the other end of the insulation. then a foil tape, or scrim and mastic, or even a polyolefin tape.

then take some hvac zip ties and sinch down the wrap onto the duct overlapping an inch or two. presumably your ducting is insulated? if not its going to condense moisture as well.

theres a number of other ways to deal with this... the simplist being a wye installed into the suction side of the fan with a volume damper. the damper is adjusted to mix in enough room air to heat up the outside air above the dew point inside your place.

if you can adjust the speed of the fan, that might help too.
you could also relocate the fan such that its behind the lights, and hence not pulling the coldest air, however fans operate a bit more efficiently in cold dense air.

 

[eyes]

Unfortuately, no matter how much they say hoods are airtight-they are not. Siver tape em closed and insert the bulb through the 6 or 8 'flange. The duct you use will also impact that as well. The new polyproplyene is better as it doesnt leak as the aluminum dryer hose. The duct you get from depot is cellophane wire scrim wrapped in fiberglass and plastic. If you can check all your duct with a hvac smoke machine, it will show you where all the leaks are. Tighten those up and pull from a part of the house that doesnt have the grow in it. If its far enough away or with a filter on it, it will keep the air odor free.

You wont have moisture issues if you have the two areas seperate. Blow the tent exhaust with all that moisture and humidity out of the home. You will have mold/mildew if you dont.

You can also take your air from the filter/ tent through the lights, and outside. You can measure with a hygrometer to see what the humidity is once its run past the lights on the end of the duct. Just another option.

 

[queequeg152]

Unfortuately, no matter how much they say hoods are airtight-they are not. Siver tape em closed and insert the bulb through the 6 or 8 'flange. The duct you use will also impact that as well. The new polyproplyene is better as it doesnt leak as the aluminum dryer hose. The duct you get from depot is cellophane wire scrim wrapped in fiberglass and plastic. If you can check all your duct with a hvac smoke machine, it will show you where all the leaks are. Tighten those up and pull from a part of the house that doesnt have the grow in it. If its far enough away or with a filter on it, it will keep the air odor free.

You wont have moisture issues if you have the two areas seperate. Blow the tent exhaust with all that moisture and humidity out of the home. You will have mold/mildew if you dont.

You can also take your air from the filter/ tent through the lights, and outside. You can measure with a hygrometer to see what the humidity is once its run past the lights on the end of the duct. Just another option.

what PP duct are you referring to? PP has poor resiliance compared to LDPE films, its mostly only used as duct in areas where good chemical resistance as well as high heat concerns merit its use.

if you dont need chemical resistance and heat resistance, generic plasticized PVC or urethane is used in its place because its cheaper.

LDPE is whats used in most if not all residential flex duct. not cellophane... cellophane would make a piss poor duct material owing to its shitty resilience and its flamability.

 

[Granger2]

http://www.homedepot.com/p/Frost-King-E-O-1-1-2-in-x-17-ft-Poly-Foam-Weather-Strip-L344H/100534592

Use something like this to [really] seal your lamps/glass. Works, holds up to heat. Good luck. -granger

 

[eyes]

what PP duct are you referring to? PP has poor resiliance compared to LDPE films, its mostly only used as duct in areas where good chemical resistance as well as high heat concerns merit its use.

if you dont need chemical resistance and heat resistance, generic plasticized PVC or urethane is used in its place because its cheaper.

LDPE is whats used in most if not all residential flex duct. not cellophane... cellophane would make a piss poor duct material owing to its shitty resilience and its flamability.

Yeah ldpe is right. I should have called it what it was instead of generalizing due to my laziness after posting a few times in the thread.

 

[queequeg152]

http://www.homedepot.com/p/Frost-King-E-O-1-1-2-in-x-17-ft-Poly-Foam-Weather-Strip-L344H/100534592

Use something like this to [really] seal your lamps/glass. Works, holds up to heat. Good luck. -granger

will that stuff cope with the heat though?

i would think some generic sillicone caulking would work, and would clean up easily... but idk what size gaps we are talking about.

 

[Granger2]

I've been using for...about 6 years. I think I read that it will handle way more than my 600w will give it. Don't remember the limit they cited, but it was more than adequate. I used silicon and it was a mess when you try to remove the glass, and upped the odds of breaking glass. It has worked well for me. -granger

 

[eyes]

Depending what air cooled hood you are running, you may want to check the flanges as well as the metal seams where the folds meet. I had mine leak from those two places before I sealed em up.

 

[thcrefugee]

Thanks for all the help everyone. I decided to just run it like I always have.
Scrubber->Fan->Hood->Exhaust (into house or out window depending on season)
I let the bedroom be sort of a lung for the tent air, But there is one duct for intake from window to tent. This keeps the tent cooler and the exhaust from running as often.

I learned that I need to: Run the ventilation like this, or to run a closed hood ventilation loop i need to:
Have two carbon filters to ensure no smell goes out. Run the intake for hoods from a different room to buffer the cold outdoor temps. Or, run the outside air thru it in not so cold months.

Of course I always push "clean" air thru the hoods, as even though its seeled with tape on the edges, they still leak air. better to push clean air into the grow space than to suck stinky air into the exhaust.

Hopefully, someone can learn from this in the future.
Again, Thanks for the help.