New grow room, venting questions

[PDXFarmer]

Hey Guys,

New guy here, bear with me.

I'll try and explain as much as I can.
Registered Medical setup on a budget
Typically I would run full sealed rooms, mini split ductless ac/heat, co2 and dehumidifier. For now this is what the budget allowed. No ac units and no co2.

Quick rundown of the rooms.
This is a new framed room/setup. 2 layers of vapor barrier between all floors, walls and ceilings. Floor, exterior walls and ceilings insulated with rigid insulation. Inside finished walls are of 3/4" r-tech 4'x8' foam board with radiant barrier, all seams taped. Pond liner floors.

Using soil = pro-mix, ocean forest and perlite


This is the design I drew up (not to scale... drawn from "paint") and it is built exactly like this

Right now just the Veg room is running. And the issue at hand is how to vent/air exchange and keep temps and humidity correct along with bringing in fresh air/co2

I have a 6" inline fan pulling air through the 3 hoods. The intake is open to the inside of the room. Keeping the lights cool and the room. But, too cool. Can't keep the temps above 65 like that. SO, I put the fan on a timer, half hour on, half hour off. And now I am getting temps of 80 with the fan off, 72 with it on. So far it has been consistent. Now, the other issue is with this method it is pulling my humidity out. Can't keep it above 55% just after watering and 40-45% the next day until the next water cycle. I Want my temps to be steady instead of spiking up and down and would like to see 60-70% humidity. I know the first thought is to add a humidifier but before I do that, is it worth it or is this venting setup just going to suck it out of the room? Also, as you can see I have my water res stored in the open hallway to the veg room. I have no passive intake to the room. There is some negative pressure and is drawing air from (dont ask me how) areas throughout I am assuming.

Fan speed controller?
Vent the fan intake from a lung room?

Or, if anyone can think of another more efficient way to vent this room please feel free to say so.

I have not setup the 2 flower rooms yet, will tackle that when it comes time. I have 2 10" max fans for those and was hoping to vent the same way.

Thanks

 

[Dutty Panty]

Have you tried getting a speed controller for your fan. It can lower the amps on the motor.
Love the layout why two bloom rooms? I did same thing and after two years just knocked that wall out.
If you want to crop every 30 days just delay each cycle 4 weeks in a bloom room.

Where are you exhausting too?
Where are you intaking from?

 

[PDXFarmer]

I think that is where I'm headed, speed controller. After last night, I'm hoping there is one that is temperature controlled. Using the exhaust in the room to control the heat is getting to be a turd with outside temps going up and down. Outside temps get a little bit colder last night and room temps dropped dramatically with the fan on it's same timed cycle.

These rooms are inside a shop, 2 of the flower room walls are exterior walls and well insulated. The Veg room and west flower room walls are inside a non insulated, non heated shop but are insulated themselves. So, a "lung room" is somewhat not available. Inside shop temps fluctuate closely with outside temps.

I had plans for an intake, considering I built the rooms sealed up tight (or so I thought) but during some practice runs with the lights and fan cycles realized that the room was still pulling air from throughout with just enough negative pressure. So the intake air right now is coming from wherever/all over. I have yet to be able to feel any air with my hand from anywhere when the fan is on. But it is pulling it from somewhere being the temps are dropping when the fan comes on. Exhaust is pulling the air from above the room. There is 10 foot vaulted ceilings above the rooms.

Previous room temps were 80-81 with fan off for half hour, 72-73 when it kicks on for half hour. Which I didn't like the fluctuation but is tolerable. This morning, records are showing it dropped down to 55 at some point last night due to the cold weather and had a high of only 76. Not good. So now I'm thinking 2 scenarios... temp controlled fan speed controller or the more expensive way which I was trying to avoid is set the intake side of the vented lights outside the room so they are on their own system and put a thermostatic controlled floor heater and ac in the room. If I'm going to spend the $500+ dollars doing that, I'm a closer step to a mini split, sealed rooms and co2 where I wanted to be but wasnt in the budget. I don't want to slowly start dumping money getting this under control and at the end of the day I could have gone into it like I wanted. But, there has to be a way to get this figure out.

Flower rooms were separated for 2 reasons, one for 30-+ day harvest cycles and another for power. We are tight on power out there so having all 8 flower room ballasts running at the same time was not efficient. Yes at the end of the month it all works out to the same power usage whether they are 8 on 12hrs, 8 off 12hrs or 4 and 4 switching cycles. Like this, there is never more than 7 ballasts running at one time. Freed up power to use.

Am I on the wrong track here... this is all new using the exhaust like this to control the room temps. Is it worth the fight or should I just bite it and get thermostatic controlled heat and ac

 

[Dutty Panty]

We spent 6500 last year on a mini split. Top of the line. A mitsubishi pulse generating multi zone. It's paid for itself 10 fold. There are less expensive units out there for sure but this beast has been worth every penny. I have photos in my garden thread somewhere. It only requires half an amp to run.

I'd never go back to Window units or Rheem heat pumps again.

 

[Dutty Panty]

I agree with your splitting the times to help the load on the power. How about wiring in another 220. I run two dedicated 220 lines to my bloom. One runs 6000 watts other runs 2400 watts.

 

[PDXFarmer]

We spent 6500 last year on a mini split. Top of the line. A mitsubishi pulse generating multi zone. It's paid for itself 10 fold. There are less expensive units out there for sure but this beast has been worth every penny. I have photos in my garden thread somewhere. It only requires half an amp to run.

I'd never go back to Window units or Rheem heat pumps again.

My last setup had 24000btu Daikin units with ac and heat in each 12x14 room (x2) cooling 6k watts hps with parabolic hoods. 2 years without an issue before my partnership turned bad and we went our own ways. Id do it again if the money was there but right now it's not. If I can get through to summer, that is the first route Ill go is back to mini splits and shit can this method.

I agree with your splitting the times to help the load on the power. How about wiring in another 220. I run two dedicated 220 lines to my bloom. One runs 6000 watts other runs 2400 watts.

Thought about it. The shop is 240 feet from the meter though. The cost in upgrading wire is not in the budget right now. I priced it out around $800 in wire. There is 100 amps at the shop but 40 of it is being used in our walk in cooler and walk in freezer (separate) Options were either pull the wire that is existing in conduit and upgrade to 150amp or dig a new trench with new wire and conduit. Next year I'll put a whole new 200 amp service.

Right now we have about 50 amps available to work with. The lighting alone is taking up 35

 

[Dutty Panty]

Yeah probably want 60 for everything.

I'd just pull cold exterior air in for now is there a crawl space? Then exit out. Obviously you are aware of that
With our temps where they are here in the nw you should be fine. As you know it's hard to control that climate without a sealed room and good climate control.

I'll take a pic of my thermostat controller shit I'm not using it I could just send it your Way. There pretty cheap if I need one again.

 

[Dutty Panty]

Yeah we got 2 18,000 btu head units in bloom.

 

[PDXFarmer]

Update:
Couple of new thermostat fan controllers with day time and night time temp settings have been working great. Daytime temps are now 78-80 and night time temps are 68-70. Been a few weeks and all is well. Now onto the flower rooms shortly.