Controller advice. Looking to control temp and humidity at the same time

After listening to a podcast about the benefits of keeping grow rooms at a stable 75%rh I want to try a test run. I need a controller that can turn on 1 exhaust fan if the temp or humidity get too high.

I’m not sure about the inkbird. Anyone have this?

I also found these, but have never heard of the manufacturer. I don’t want a piece of crap.

Any other suggestions?


Lotsa people seem to use this with great success.


Which one ?

Idk bro, to me a controller is only half of what you need. Take heating and cooling for instance. The inkbird you listed has 2 switched outputs. So you can control a fan and 1 other device. You could probably setup the other device as humidifier or dehumidifier based on season, but it will have to be able to change conditions quickly. And it won’t have the ability to communicate with any other devices. It will stop fan and start humidifier when rh gets low. But what happens when temp becomes out of range but you haven’t reached rh setpoint?

Imo if you’re looking for exact control, you should probably remove exhaust from control and have it run just enough to meet minimum air exchange requirements. Then use independent controllers to control temp via heater or ac, and rh via humidifier or dehumidifier. And that sounds really expensive to build and run.


I use the inkbird for temp control and can’t fault it. I run two dehumidifiers constantly in the same room that my tent is in. The only way I could see it being a success would be to have the control gear in the tent and the dehumidifier outside. As soon as the temperature control steps in it will evacuate the humid air and hopefully draw in the drier air. Compressor dehumidifiers won’t go much lower than 50% so you could leave it on constantly

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I guess I should’ve given more info on my setup.

I’m in an enclosed and insulated grow room in the basement.
Fresh air comes in via a filtered light trap pulling from the basement environment. The basement is running a dehumidifier that can easily pull the rh down to 40% in the summer. Basement temp ranges quite a bit, from 60-75 in the summer, and 45-60 in the winter.

The exhaust goes directly outside in the summer and is recycled and filtered into the basement in winter.

I have a humidifier, it does not have exact settings, Just min-max but can be switched on/off with a controller
I have a small space heater, it a has temp settings.
I also have several stand alone temp controllers and an rh controller.

I wouldn’t object to 1 stand alone control unit, like a titan, but I couldn’t find one that fits my needs. I’d prefer to keep the cost reasonable ($200±). I could go to $400, but I’d rather not.

I also have a couple window a/c units. They are not installed.

I’m just trying to figure out how I can, or if I can, “cheaply” keep the environment stable at a high rh without hitting the dew point on buds after lights out.

Inkbird has individual controllers, too. I know nothing, really, except what I’ve seen posted in the forum.

This is in my shopping cart, though:

Inkbird ITC-308 Temperature Controller with IHC-200 Humidity Controller


I’ve heard good things about inkbird.


I think @VTGROW is running these. Let’s see what say he.
Maybe that was @Zee to stoned to remember.


Right, but they are still digital control and don’t communicate with each other. It puts you into position where one is always slave to the other.

I started to explain above then went off track. All of the equipment we’re typically getting is on/off. You any unit you plug into those inkbirds will run until it reaches set point then shut off. There’s no consideration for when one item is trying to bring temp up while another may be trying to bring rh up and they end up fighting each other.

In industrial setting we use pid or closed loop control. That is where output is controlled on analog level from feedback given about conditions. This is linear ramping of fans, self adjusting of heaters, loading refrigeration units differently instead of just having them on or off.

This stuff plenty good enough for what most of us are doing. But it leaves a lot of holes in setting and forgetting.

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This is what I was thinking. Please correct me if I’m missing something.

If I use a controller for the exhaust fan, that will switch on if either the rh OR temp get too high, It will suck in fresh air from the lung room that’s cooler and much drier. This will essentially keep the temp and rh around where I want it.

I can plug the heater into a thermostat, and I can plug the humidifier into a humidistat. That way either of them come on and shut off when they hit my desired level.

I’m sure using separate controllers for the exhaust fan, humidifier and heater, will take some dialing in. Maybe it won’t be precise enough? Too much lag and up and down ?

I’d love to buy a stand alone unit. I just don’t want to have to sell my house to get it.

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This goes without saying. Also, I am neither a proponent or against this automated stuff, just answering a post from a HOME grower.


I appreciate all the input.
Sometimes I need a less myopic view, and professional input is always greatly appreciated.


From what I’ve seen on forums, home growers seem fairly satisfied with the set-up you’re thinking about.


I think it will work pretty good, with exception being those random days you get large swings in climate. I’m probably over critical because we have shit weather like that here. A couple of weeks ago it was 52 degrees when I left for work and 90 when I left to go home.

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That’s all we have here for weather. Sh!t…

It’s a relatively small room, and since I use the basement as a lung room, the intake air is fairly consistent. Or at least very slow to change.

The true challenge will be trying to keep rh @70-75% without hitting dew point on the buds at lights out. I may have to stagger the timing on lights going out to prevent that.

If I screw up and get bud rot or wpm I’ll be kicking myself, but at this point in my “hobby” I’m focused on improving the end result vs. quantity. (The high humidity in flower is actually supposed to prevent wpm, which I’m still haunted by).

I think making the plants as happy in their environment as possible is the key.

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I’m in basement too, my rh stays about 70% without much effort. I’m just having hard time getting temps as high as I would like.

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Ha. In the summer-fall, I have no problem with getting the temps up. I’ve got the exhaust fan cranked almost all the way to keep temps under 82f. I could get the rh as high as I want just by turning down the dehumidifier.
Winter is when it’s tough to keep Rh & temps in the high 70’s. Sometimes I feel like I’m burning money to stay warm in there.

I’m just dialing it all in now. New space=new challenges.

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Without a doubt. I could run small heater down there and get temps in check, but my wife would kill me. I’m running my fan on 2nd from lowest setting and have light cranked, can’t get above 75f. They will all buff out.

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My wallet kills me.
That electric bill… ouch.
It’d be cheaper to buy weed from a guy…:joy:

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