The Smart Growth Blog

Ductwork - Get it right or fail

Written by Geoff Brown | Mar 30, 2023

In this episode of FAQ with AGIQ, we're going to talk about ductwork - It really is one of those things that you either get right, or you fail your facility.


Episode Transcription:
In this FAQ with AGIQ, we're going to talk about ductwork. I've spoken about ductwork, I've written about ductwork before, but it really is one of those things that you either get right or you fail your facility. It's really that simple. Ductwork is what you use to get your conditioned air from your air conditioner / dehumidifier into your space in an accurate way.

And getting it wrong is going to lead to things like space stratification or hot spots or cold spots in your room or an uneven canopy temperature. All of these things are bad, but ductwork is one of those things that's so often ignored in facilities, it really boggles the mind. It's a relatively cheap thing to get right. A typical flower room might only cost $10,000 or $15,000 to get good ductwork installed, but if you're not getting ductwork that gets air down to the plants, to the canopy.  If you are return air system doesn't compliment your supplier. That is, we don't want office style - you know those two-by-two office style diffusers that you see in a in your dentist office, that's not the right choice to get air all the way down into your room through your canopy. So your conditioning your canopy, that's what the air conditioner’s there for - that's what your HVAC system is designed to do.

So you have to get that air where it needs to be, and a properly designed ductwork system is really the number one way to do that. The other thing about that, is trying to ensure that you're not making design choices that force a room to stratify. So, think about having lighting, you've got horizontal air rotation fans in your space, you've got high supply and high return.

How many of you have seen a grow room like that? Probably most of you. I see them all the time. What you've got there, though, is with high supply and high return, you've got a natural tendency for air to go from the supply, which is positively pressured, to the return, which is negatively pressured. You've got a layer of lights blocking that air from getting below, or at least somewhat so and then you've got a horizontal air rotation system in that space wall fans that are providing an air curtain.

Again, you've all walked into a store and get blasted by air at the door. Know your local Costco or Sam's Club does this to you. That air curtain works the same way in a grow room as it does at that store and prevents air from mixing between those two conditions. What that leads to is a very stratified space.

You'll have a very cold airstream above your lights, nowhere near your plants, while your plants are cooking. It leads to your HVAC system struggling to keep up, it’s seeing vastly different air temperatures than your space is seeing or then you're trying to control to, leads to extended runtimes, lowered life, higher energy costs, and ultimately, you're going to be unhappy with that space.

And all of that could have been saved with just some intelligent airflow design. It's a cheap thing to do for the space, but it's absolutely critical and you can't let it get away from you.

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