I am getting my first indoor grow setup, and was just wondering how hard I should try to design my ventilation to account for dropping the temps at night. I will be using LED so there wont be THAT much heat differential when they shut down, and my intake pulls from inside a dwelling, so the air will be 70ish most of the time anyway. I know they make automated fan speed controllers, but is it really worth the money and effort to buy TWO $100ish controllers and get them dialed exactly in to a day/night + idle type of deal? Or should I just dial it in by hand with a Variac and leave the air movement the same at all stages of growing?
dropping the temperature at night isn't super important. especially when starting out, keeping a consistent temperature is far more important. keep things simple. i would recommend picking up a fan controller for each fan, if you don't need them to be full power to keep the room cool then there is no reason to use the extra electricity. Fan controller
Look into inkbird temp controllers. It's like 30$ and you can hook up your exhaust fan to it and set the high and low temp . Your fan will turn on when temps reach X and off when they hit Y
The only problem I see with that is if my temps could stay warm or cold enough for a bit, I have zero ventilation in the space until the temperature changes enough. The only unit that really "does it all" that I have seen is the Mercury 5 by Titan... That unit can set a fan speed for if the temp gets over or under a certain point, as well as an idle speed to always run even if it is below or above the required temp. It also has separate settings for night time, so this unit could achieve a temperature drop when the lights are out. However for 90 bux, I can probably get 2 variacs for that and then cut down on the noise a bit, but not have any variance in fan speed when it comes to temperature or lights being on or not. Something like...
Do not worry about it at all. I also grow indoors in a controlled (Thank god for central air) 70 degree environment. I use just under 600 watts of actual wall draw LED lights and the temp difference is about 6 degrees between lights on and lights off. I use a 6" exhaust fan in a 4x4x7 tent with a variable controller keeping fan on lowest setting running 24/7 for odor control. I allow the negative pressure to draw intake air from the tent screened openings near the floor. 5 to 6 degrees difference in on/off temp is constant.
Thank you much for this! My setup is going to be very close to this other than an active air intake pulling air from inside the house. Now to get building!