Modern HVAC for 1600 sq ft LED Grow

Hi All,
Is there an HVAC consultant on the threads who can help me plan my new grow facility environmental controls? I’m happy to pay a reasonable fee for the service as well.

I’m located in Rural Montana so there’s def. not a grow room specialized HVAC service nearby but there for sure, many experienced commercial installers. If we can get a plan together, I can pass the instructions for them to follow.

  1. I’d like to be as energy efficient as possible without a MONSTEROUS increase in upfront cost.
  2. I’m venting my grow air out with 12" can fans which controls heat fine but drys out my room too much. I use the humidifier more than the dehumidifier.
  3. Montana climate is fairly mild except in the heart of summer/winter. I won’t be using the Heat/AC much more than maybe 3 months a year.

The rooms have 10 ft ceilings. I’m slightly confused as to where my exhaust intake should be in relation to my lights and the incoming AC/Heat. I don’t want to just suck it up and exhaust it as soon as it comes into the room.

Do I need to pour additional concrete outside for a AC pad or should this be a unit in the roof?


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@Myfriendis410 @dbrn32 @MattyBear

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Roof locations are maintenance problems IMO. And you don’t need to pour a pad for an A/C unit: they use a plastic pad at installation.

Unfortunately you will need to be prepared for the worst conditions you may encounter. Conditioning the air without exhausting too much of it (for air exchange) is the problem. Maybe think about a closed-loop system: CO2 at a high partial pressure then condition the air in that space without exhausting or infusing fresh.


I’m going to pretend I understood what you said :slight_smile: Should I tell the technician that?


As a maintenance technician for a high rise complex of 200 units with rooftop condensers I would agree with that statement


Where is a good reference point to look this kinda info up?


Look around here: there are some serious growers on the forum and a little research will inform your decision-making. Attaching yourself to one of them is good as well if you find someone to mentor you.

Here are a few folks I’d pay attention to. Not to say there aren’t many more, just a quick list.

@Not2SureYet @peachfuzz @Bogleg @Big123 @repins12 @Covertgrower @TDubWilly @imSICKkid @MrPeat @Missiles


Happy to help in any way I can, as well as any of the others listed and many more. As a community we want everyone to be successful in growing.


Now this is a pretty neat design. Set to watch. I bet yiu didn’t know of my Architecture and Drafting classes I took.

@Myfriendis410 :hugs::hugs::hugs:


I’m tuned to watching and willing to help in any way that I can, just let me know :+1::v:


I think you are on the right track by planning thins out as much as you can before you pull the trigger. I am finding that working with a full room as to a tent is more of a challenge. My air intake is right across from the outlet. Some thing I want to change in the next grow.
As @Myfriendis410 showed me. When you are in veg and early flower. You can run an exhaust fan through veg pretty easy. If my room was sealed from the rest of my house more. I would run the fans on timers now in flower as well. And be able to run the dehumidifier a little more. Once you have it set up. One grow will show you how to fine tune it to fit your needs. I am going to tag along too :grin:


Hello peoples!!!


You can buy a precast slab for condensing unit if need be. Based on layout of your building, do you need hvac for the entire building or just the grow room? If you will need heat and/or cooling at all it will probably be best to go with ductless split style for grow room. They are available with heat, and multi zone from one condensing unit available as well. Won’t be cheap, but will work the best for your grow room.


As you can reference in the layout blueprint, I’ll be dropping ducts into multiple rooms (not only the flowering rooms). I also have a dispensary and work room that gets very hot in the summer. I’d love some advice on where to place my air inlets/exhaust in relation to the ac/heat ducts and lights, canopy etc. Seems like there could be some trouble adding in cool air and just sucking it right up the exhaust fans.

The heat is coming off the lights, 18" above the canopy but I will have airflow as well. The surrounding environment needs to be exchanged for fresh 400ppm CO2 air.

Maybe you have some insight into the proposed blueprint? (1st post) and additionally placements of exhaust vents or inlets so they play well with AC/Heat ducts and the heat sources (lights above the canopy)? Thanks in advance… :slight_smile:

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What would you do differently in the next grow? Curious is to what works/doesn’t with your intake/exhaust placement…
Thanks in advance.

Here’s a WIP of the addition:


Ductless heatpumps work well for small set up but the maintenance can be a issue. You’ll be pulling the blower wheels out to clean them about twice per year and its a pain.
If cost was not a issue I would have the flower and veg room on one unit and zoned so you would have a stat in each room bring your makeup air(fresh air) in to the unit return so that the air is filtered. Bosh makes some really nice Variable speed condensing units that would help control humidity better.
The other two rooms I would put in mini splits

Tons of options really but you must have a heat load done including lighting so it can be sized properly.


I know it’s a rough draft, but how many diffusers are you planning for in the flower room? I see 4 “ducts” but I wasn’t sure if that would be the same as diffusers or not.

What kind of lighting do you plan on using… ?