How to automate vent opening & closing based on room temperature? Need help!

I have a dilemma .. I am using a 16x20 outbuilding to house a small grow, split into separate vegging and flowering rooms. I live in Michigan so the temps vary wildly between winter (sub zero) to summer (100+). I'd like to find a way to vent my cooltubes into my growing area during the cold winter months, but then redirect that hot air outside when it gets too hot in the room. I have a separate exhaust with a carbon filter constantly pumping flower room air outside and pulling fresh air in through a filtered passive intake.What is the cheapest way to do this? Any ideas at all would be greatly appreciated, thanks!!

Get yourself a suncourt ductstat. Its a thermostatic controlled on off temp control. You can mount it to ducts or just leave it in the open like I do and have it turn my intake on and off to regulate my temps.

You can pretty much use it to control anything. It just has a 5 amp max and a plug on it and control to set the temp. Very easy to set up and use.

I do what you're talking about at my home. In the winter I blow the heat up the basement stairs into the rest of the house, and in the summer I take that same duct and have it blow outside a basement window. Maybe you could just change the duct's exhaust around, though this makes spring and fall actually the hardest times to regulate.

They do make automatic dampers with thermostats but that is not the cheapest way to go.

Yes automatic damper, ( damper with actuater) open and closes on thermostat or when fan kicks on

yup like this. You will need a transformer to operate it tho.

http://www.globalindustrial.com/p/hvac/registers-ducts/diffusers/aprilaire-round-motorized-damper-8-200mm?utm_source=google_pr&utm_medium=cpc&utm_campaign=Diffusers-google_pr&infoParam.campaignId=T9F&gclid=CMT7s6TP7rUCFQmxnQodBlsAHA

I was talking about the this...

I was responding to jrainmans post. The ductstat will only turn a fan on and off That is fine for his fan I would choose a different one personally. He wants to vent his flower room back into his veg room based on overall building temps. A couple of zone dampers could do this completely automatic in conjunction with some sort of thermostat or two. As well as a transformer cuz the zone dampers operate on low voltage.

joe macclennan said:

yup like this. You will need a transformer to operate it tho.

http://www.globalindustrial.com/p/hvac/registers-ducts/diffusers/aprilaire-round-motorized-damper-8-200mm?utm_source=google_pr&utm_medium=cpc&utm_campaign=Diffusers-google_pr&infoParam.campaignId=T9F&gclid=CMT7s6TP7rUCFQmxnQodBlsAHA

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I live in AK. I wouldn't have this thing controlling outside air or even connected to my room in the winter. Michigan is even more brutal with unreal cold & humidity in winter.

hotrodharley said:

I live in AK. I wouldn't have this thing controlling outside air or even connected to my room in the winter. Michigan is even more brutal with unreal cold & humidity in winter.

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This "thing" is a zone damper. It can be utilized easily to redirect air back into his veg room. Which is what he wants to do. If cold air leaking back into the room is a concern a backdraft damper could also be utilized.

but thanks for your rather helpful advice. You have a better option to allow this op to redirect cooling air automatically when it is appropriate based on room temps. Or are you just trolling again?

I am well aware of the climate in michigan. I go there frequently.

probably the cheapest route for you would be to use a couple of manual dampers. http://stores.hvacexpress.com/-strse-In-dsh--Line-Dampers-cln-Manual-Dampers/Categories.bok

along w/a fan and thermostat.
With this method you will have to be johnny on the spot opening or closing the dampers according to where you want the air to go.
Whichever way you choose a backdraft damper is probably a good idea to prevent cold air from coming back in when the fan is off. Bout 30 buks on ebay.

joe macclennan said:

yup like this. You will need a transformer to operate it tho.

http://www.globalindustrial.com/p/hvac/registers-ducts/diffusers/aprilaire-round-motorized-damper-8-200mm?utm_source=google_pr&utm_medium=cpc&utm_campaign=Diffusers-google_pr&infoParam.campaignId=T9F&gclid=CMT7s6TP7rUCFQmxnQodBlsAHA

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This is perfect! One of these that's normally open + one that is normally shut + thermostat + low volt transformer and I will be in business. Is there any reason in particular you listed the one you did? I found a few cheaper with a quick search from different brands... but is there a wide quality difference from manufacturer to manufacturer?

joe macclennan said:

probably the cheapest route for you would be to use a couple of manual dampers. http://stores.hvacexpress.com/-strse-In-dsh--Line-Dampers-cln-Manual-Dampers/Categories.bok

along w/a fan and thermostat.
With this method you will have to be johnny on the spot opening or closing the dampers according to where you want the air to go.
Whichever way you choose a backdraft damper is probably a good idea to prevent cold air from coming back in when the fan is off. Bout 30 buks on ebay.

Click to expand...

This is similar to what I've been doing, only by manually switching the exhaust vent instead of using dampers... it works, but like you said I have to remotely monitor temps and have to constantly change the vents based on outside temps, especially during season changes or unseasonably hot/cold temps. I have thermostats controlling my AC and my heating, so this was the last part of my temperature regulation that I had to do manually.

Yep, you got the idea. No reason for picking that one. Just the first one I found in a quick google search. Make sure you get a voltage transformer as these typically run on low voltage. Easy peezy to hook up. Again, most of these zone dampers do not shut tight so some backdraft will occur. I recommend putting a backdraft damper directly before you exit the building to prevent any cold air from feeding back in.
Enjoy your project. If done right you will be very happy w/the results.
glad I could help.

joe macclennan said:

Yep, you got the idea. No reason for picking that one. Just the first one I found in a quick google search. Make sure you get a voltage transformer as these typically run on low voltage. Easy peezy to hook up. Again, most of these zone dampers do not shut tight so some backdraft will occur. I recommend putting a backdraft damper directly before you exit the building to prevent any cold air from feeding back in.
Enjoy your project. If done right you will be very happy w/the results.
glad I could help.

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I appreciate the advice, thanks!