Was venting out the window a couple months. Occasionally a little smell outside, but acceptable.
Side trip: My understanding is that the air venting from a portable AC is not the air from the space being cooled, so should have no smell. Always wondered about that, like, where does that air come from? The airflow genie?
Back to the main subject. Friend who works HVAC came over and ran the vent up in the attic for me. Idea was that even though the smell is still eventually getting out from the attic vent, that it is so much more diffuse, and probably filter a little by the insulation, that it would be a good improvement.
So far so good! Super stinky flower room, not a hint outside. Occurred to me that the attic vent is like 22 or 25 feet up in the air. Make me think that maybe something stinky coming out of a vent that high above where everybody’s noses are might just dissipate quickly. If anything, maybe a smell several houses down, or even a b lock or two away.
Anyone do this before? How was the smell reduction?
With a single hose setup your portable ac will draw air from inside the room(i.e. smelly) to cool the compressor and vent it outside. There are dual hose configurations out there that seal the compressor and coils separately. Using one hose as an intake and the other as exhaust, cooling the compressor with outside air and leaving all your stink-em-good inside.
Down side? They’re about double what a single hose portable ac costs.
Are carbon filters not an option? I have a 6" in both my 4x4 and my 5x5 that vent into the lung room and an ac that vents out the window. Filters clean the stink so the ac has nothing but clean air to exhaust.
Ah, that explains a lot, thanks! Kind of surprised we were able to get away with it for 2 months. Whew…
The setup is the entire room, about 12x15 I think, with 2 lights, so 50ft2 of canopy. I do have a pair of filter fans set up that remove a ton of smell. They are just 20" box fans with 20" MERV-12 filters taped to the input side. Its like 45 bucks per. From what I can tell, if we were going to do it like a tent, but room sized, we would need a very large filter, like one of those Cann Fans, and they expensive.
Was mathing it out. Standard 8’ ceiling gives you 1440ft³ of air volume. Standard practice is to refresh the entire room volume every 3 minutes. A high cfm 6 inch fan and filter could handle it. It would be easier for an 8". 8s start at the 720cfm giving you 2160ft³ of moved volume every 3 minutes, well over standard air exchange practices.
Still you’re correct. Not exactly cheap, 150-200 from Amazon for fan and filter(8")
The wife’s only stipulation about me growing was the house couldn’t smell like it. So I spent some time down the “clean air” rabbit hole. I can see the merv12s doing an OK job. Carbon filters are more specifically focused toward smell absorption than particulate capture.
I did see one of those merv-12s that offered a carbon layer to the filter. Might help if you’re not already using it.
Thanks for mathing! The room has a sloped ceiling, going up about 9.5 feet, so it sounds like an 8" would be the way. Thats much better than I expected, figured I would need either a pair of 8" or a massive Cann Fan. Last I checked they started a little over $500. That’s pretty encouraging, thanks again!
Curious about something: a rating of 720cfm applies to the fan correct, not the flow that actually comes out of the filter? Are there some kind of ratings for specific filters that would allow us to calculate how much air flow is getting through the filter?
Good question! After some looking, a carbon filter can drop cfm 10-25% so at max loss you’re still looking at 1620ft³ so I’d say it sounds perfect.
