Exhausting outside....make up air?

Just wandering what needs to be done to maintain indoor air quality when there's such large volumes of air being pumped out.

Is there something you can buy or make to temper and filter outside air before it's mixed with conditioned indoor air?

I mean we ain't talking periodic 200-300 cfm bathroom fan or range hoods, these can-fans and hyper fans move massive volume and are used for extended durations.

Help me understand.

https://www.icmag.com/ic/showthread.php?t=112862

Usually a good idea to set up a lung room. The link above is loaded with solid information.

I'll get to reading!....for a while. Thank you.

"Lung room".....you learn new things every day.

Be careful in the winter, it's easy to overcome your chimney draft with today's fans and kill your family pulling the furnace exhaust through the house.

That's what I'm talking about! Only so much air can seep in around the outlets and ceiling boxes.

Chunkypigs said:

Be careful in the winter, it's easy to overcome your chimney draft with today's fans and kill your family pulling the furnace exhaust through the house.

Click to expand...

You might be surprised how even low cfm fans can do this in the right conditions. Good tip. If your furnace (or gas log, etc) has negative pressure venting, gotta supply intake air to your growspace from some where.

How does one bring outside air while not getting environmental debris (pollen, grit, grime, bugs) brought into the grow area.

Also what about the temperature differential. You can't bring 10°-20° into a growroom.....?

Fitz carraldo said:

How does one bring outside air while not getting environmental debris (pollen, grit, grime, bugs) brought into the grow area.

Also what about the temperature differential. You can't bring 10°-20° into a growroom.....?

Click to expand...

Pollen, grit, grime, bugs can be fixed easily with a filter on the intake. Like a hepa filter that is tight enough to stop that stuff, but large enough to allow the volume of air you need to get into to the room. Some grow specific ones, or you could make one out of any hepa filter you can find.

The cold air should be ok, just have to set the fan on a thermostat, so it shuts off before the temp gets to low. It may cause condensation, so you will have to adjust, dial, tweak stuff to get it all working right. Ventilated rooms can be tricky, the outside environment will play a role seasonally.

As far as bringing the air in, need to cut a big enough hole somewhere, to allow the amount of air in that you need. Sawsall's work well. Handful of options on where to cut a hole.

Your attic air is most likely warmer, but you would have to exhaust somewhere else so your not in taking the air you just exhausted. The floor can work really well, just be careful not to hit a joist. The air under the house is most likely warmer than outside as well.

Personally, I prefer a sealed environment. You can dial in a sweet room with an exhaust, but just easier to seal it up and release Co2. Need an AC, Dehumidifier, and a source of Co2, to do it right. Add in the fancy Gavita master controller, with the auto dim, and your environment will be nice. If that is out of your budget though you can dial in a nice ventilated room, just got to spend some time in the room adjusting and monitoring until you get it nice and stable.

GL,
Mr^^

Here is what I am attempting to build: https://www.youtube.com/watch?v=baHbOtkbgwY

I am going a different route though, and using shorter pipes but more of them, in a manifold configuration.

Not sure if I want to use 3 inch pvc pipe with pop cans like in the video, or 4 inch sewer pipe with 3 inch flexible aluminum ducting. As long as the air space is the same both inside and around the aluminum core so they both flow the same amount it should be good to go.

Also mine will be vertical so all the condensation will go right to the bottom to be collected. It really won't take up a whole lot of room, and be right up against a wall only sticking out 4-5 inches.

Why buy an expensive heat recovery ventilator, or even 2 units (were talking 1-3000 dollars here!) that still won't out perform some cheap ass sewer pipe with free soda cans slapped together..

simply have the air coming from outside going through a furnace filter in a box or something. I like to buy the ones that filter the most allergens.

be careful, one mistake i made is intaking more air than exhausting in my basement which created positive pressure and made some of the wall sweat from having warmer air trying to exit the basement's poorly insulated walls..

A filtered and powered intake maintains positive pressure in the grow area. Variable outlet vents keep the air flow and temperature correct.

Sucking air in through every nook and crack in the building does not make for good air quality. Bugs, pollen, hair, bacteria, any airborne pollutant will suck right in. Positive pressure keeps 100% of these contaminates out. Humidity is controlled as well, the wet air is pushed out with the heat.

Three spidermite infestations and uncounted fungus gnat invasions all stopped and never came again after pressurizing the indoor gardens with filtered air.
I am a fan (pun intended) of powered intakes with filters.

I have been playing with Heat Recovery Ventilation ( google HRV ventilation) on a few grows here in MI. We have such wild temp swings throughout the year, conventional thinking doesn't always work, at least not efficiently. I don't like to run A/C, ever.

I bought my initial unit, like those in your search results, for my super-insulated home...

My current setup for a room using an 8" exhaust is to have the 8" exhaust duct into an 8"x24" duct and then run about 20' out of the building. Inside of the square duct, I run 2 8" intake ducts. They run all the way from the room to outside and then have 90* elbows going down to within 2' of the ground, install a screen here and a filter at the other end in the room...

After all of that...you use your warm exhaust air to pre-conditon your incoming intake air...

Out of the norm as far as grow rooms are concerned, but used worldwide in the building industry...

Any questions, feel free to ask.