I started my first grow last May and ran through the summer, harvesting a couple of weeks ago. The temps here (Oregon) were 70 - 90 but my grow room which is in my shop stays cooler than the outside temperature (70's to mid 80's). This worked great for the summer months. The only issue that arose is that I had to buy a chiller to keep the roots in good shape for the weeks where the temp exceeded 80*F.
Now I am about to start grow #2 and it occurred to me that the opposite problem needs to be addressed which is how to keep my grow room heated in the winter since the room is in an uninsulated shop. The grow room will be insulated however.
My room is 7' x 8' with 8' ceiling. I currently have a 6" intake fan sitting outside the grow room (but inside the shop) blowing air in. I have an 8" fan mounted to the ceiling inside the room, pulling warm air from the room, blowing through the hood (glass intact), then out the room. Both fans have filters and I ran them 24/7 throughout the first grow.
So for this next winter grow, I have been thinking about taking the glass out of the 1000w HPS hood and then reconnecting the ducting so that air is exhausted without going through the hood so that I can use the heat from the light to help keep the room warm. I would think that this would still be pretty inefficient though since I am drawing cold air from outside the room through the intake fan and then the warmest air at the ceiling is still being blown out fast with the 8" fan. So my first question is; can I put both fans on a timer or thermostat so that I can let the heat stay in the room longer? If this is OK, how long can the fans be off without causing issues with the plants? In other words, how often does the air need to be recycled?
Next; I read where some folks state that they shut off their exhaust fan but not the intake fan. I don't understand how this would work? My room is completely enclosed so the only place air could escape would be around the door. I doubt that the small seams around the closed door would allow enough air to escape. I think the room would become so positively pressurized that my intake fan might fail. Please advise regarding this issue.
There are a couple of other options I would appreciate some advice on. First, I have an oil furnace (normal home furnace) in my shop that I use only to keep the shop from freezing in the winter. I could run some ducting from the furnace to the grow room and put the thermostat inside the room. The issue here is that when the furnace kicks on, again, the pressure in the room would be positive for the short time the furnace is running. I don't know if this would negatively affect the fans, plants, or the humidity in the room?
The last option that I can think of is to buy a combo AC/heater unit like a LX-140 WITH 14,000 BTU AC AND 14,200 BTU HEATER. I like this idea because I could control temp and humidity year round but I don't understand how a system like this would work with intake and exhaust fans? This unit draws air from outside the room and expels back out again so there would be no air exchange with outside (fresh) air. So if i understand correctly, with this unit running, and no supplemental CO2, I would still need to run the fans which leads me back to the problem of rapidly expelling warm air from the room. I have no idea if the unit could keep the room warm faster than the fans would expel the warm air. It seems like the opposite problem would arise in the summer when the unit tries to keep the room cool but the strong fans would remove the cool air faster than the unit could keep up? So again, I guess I am back to how long do the fans need to run?
I have no experience with any of the options above so my assumptions are just that. My assumptions may not be accurate so I would really appreciate any advice you could give based on your experiences. I would love to hear other ideas also. I really don't want to wait until next spring to start another grow yet I need figure out a way to efficiently keep the room warm for the next several months if I want to grow antoher crop.
TIA
Now I am about to start grow #2 and it occurred to me that the opposite problem needs to be addressed which is how to keep my grow room heated in the winter since the room is in an uninsulated shop. The grow room will be insulated however.
My room is 7' x 8' with 8' ceiling. I currently have a 6" intake fan sitting outside the grow room (but inside the shop) blowing air in. I have an 8" fan mounted to the ceiling inside the room, pulling warm air from the room, blowing through the hood (glass intact), then out the room. Both fans have filters and I ran them 24/7 throughout the first grow.
So for this next winter grow, I have been thinking about taking the glass out of the 1000w HPS hood and then reconnecting the ducting so that air is exhausted without going through the hood so that I can use the heat from the light to help keep the room warm. I would think that this would still be pretty inefficient though since I am drawing cold air from outside the room through the intake fan and then the warmest air at the ceiling is still being blown out fast with the 8" fan. So my first question is; can I put both fans on a timer or thermostat so that I can let the heat stay in the room longer? If this is OK, how long can the fans be off without causing issues with the plants? In other words, how often does the air need to be recycled?
Next; I read where some folks state that they shut off their exhaust fan but not the intake fan. I don't understand how this would work? My room is completely enclosed so the only place air could escape would be around the door. I doubt that the small seams around the closed door would allow enough air to escape. I think the room would become so positively pressurized that my intake fan might fail. Please advise regarding this issue.
There are a couple of other options I would appreciate some advice on. First, I have an oil furnace (normal home furnace) in my shop that I use only to keep the shop from freezing in the winter. I could run some ducting from the furnace to the grow room and put the thermostat inside the room. The issue here is that when the furnace kicks on, again, the pressure in the room would be positive for the short time the furnace is running. I don't know if this would negatively affect the fans, plants, or the humidity in the room?
The last option that I can think of is to buy a combo AC/heater unit like a LX-140 WITH 14,000 BTU AC AND 14,200 BTU HEATER. I like this idea because I could control temp and humidity year round but I don't understand how a system like this would work with intake and exhaust fans? This unit draws air from outside the room and expels back out again so there would be no air exchange with outside (fresh) air. So if i understand correctly, with this unit running, and no supplemental CO2, I would still need to run the fans which leads me back to the problem of rapidly expelling warm air from the room. I have no idea if the unit could keep the room warm faster than the fans would expel the warm air. It seems like the opposite problem would arise in the summer when the unit tries to keep the room cool but the strong fans would remove the cool air faster than the unit could keep up? So again, I guess I am back to how long do the fans need to run?
I have no experience with any of the options above so my assumptions are just that. My assumptions may not be accurate so I would really appreciate any advice you could give based on your experiences. I would love to hear other ideas also. I really don't want to wait until next spring to start another grow yet I need figure out a way to efficiently keep the room warm for the next several months if I want to grow antoher crop.
TIA
