Grow tent heater suggestion?

jonnynobody

Well-Known Member
My basement grow tent with the inline fan on circulating fresh air in and out drops to 70 degrees F. A bit cold for clones and seedlings. What type of heater would be best to place inside of the tent? I don't want to strip all of the humidity out of the tent which seems to be difficult with any type of heater that's not oil filled and radiated.
 

MichiganMedGrower

Well-Known Member
Im about to set up a tent in my 50 degree open porous walled and old unfinished floored basement.

Im going to leave space in the 4x8 for an oil filled radiator heater on low and the circulation fans will blow the heat around as it mixes with the air intake. Exhausted into the room with the tent (plenty of fresh air available as basement is not closed off from the house).
 

jonnynobody

Well-Known Member
That's kind of what I was leaning towards. They suck down a lot of power but they don't drop the RH like forced air heaters and I feel like they're safer. I have a tray of 8 seedlings and 4 5 gallon hempy buckets on the floor right now, so floor space is very limited at the moment for the oil filled radiator. I wound up buying one of these (https://www.target.com/p/honeywell-360-surround-indoor-heater-black-1500w-hhf360b/-/A-49107839) to place inside of the tent set to low (750 watts) with the thermostat set to kick on anytime it dips below 75. If it takes the RH down too much then back it goes and I will bite the bullet and move my 8 seedlings to another room so I can put the electric radiator in there. I have a strong feeling that I may wind up returning the heater I bought today for the oil filled radiator. I'll report back later once I have it up and running and give it a few hours to test things out with the ventilation running. Lights don't come on for another 2 1/2 hours and I'm chomping at the bit here :)
 

MichiganMedGrower

Well-Known Member
That's kind of what I was leaning towards. They suck down a lot of power but they don't drop the RH like forced air heaters and I feel like they're safer. I have a tray of 8 seedlings and 4 5 gallon hempy buckets on the floor right now, so floor space is very limited at the moment for the oil filled radiator. I wound up buying one of these (https://www.target.com/p/honeywell-360-surround-indoor-heater-black-1500w-hhf360b/-/A-49107839) to place inside of the tent set to low (750 watts) with the thermostat set to kick on anytime it dips below 75. If it takes the RH down too much then back it goes and I will bite the bullet and move my 8 seedlings to another room so I can put the electric radiator in there. I have a strong feeling that I may wind up returning the heater I bought today for the oil filled radiator. I'll report back later once I have it up and running and give it a few hours to test things out with the ventilation running. Lights don't come on for another 2 1/2 hours and I'm chomping at the bit here :)

That looks nice. Please report results. I will be cleaning out my basement soon for my build.
 

jonnynobody

Well-Known Member
Very nice little heater. However, it dropped the RH too much. I was hovering around high 20's. I traded out the new heater for an oil filled radiator I had heating a basement bedroom. The radiated heater definitely takes the RH down, but not nearly as dramatically as the forced air heater. The tent stays right at 40-50% now. Seedlings are happy, clones are happy, and poppa bear is happy :)
 

shimz

Well-Known Member
May not work in your situation, but I finally got around to installing a ventless natural gas wall unit for extra winter heat and I'm kicking myself for not doing it sooner. Not only did it heat up my minimally vented space to the right temperature, it keeps the RH up to combat the dry winter air and as a bonus CO2 levels are consistently over 1000ppm now!
 

Fatmat19

Active Member
Probably not going to interest any of you but I use a 250watt heat lamp since I’m growing outdoors in the middle of a Michigan winter it never gets too hot, I have to use a space heater as a backup for really cold nights and when I open the door.
I block the light by having it in a metal trash can with dividers in the middle to block the light coming out the hole on the opposite side where I have a computer fan blowing the heat into my room.
For a duct system you could pretty easily and cost effectively place a lamp in a heat box connected to the cold air supply. I’m not sure but my theory is since it’s a sealed heat source it doesn’t affect RH at least not by much.
Also not sure how much heat that would put into your area but there are lower wattage bulbs that produce heat and being in a duct the light shouldn’t be an issue like it is for me
 

Renfro

Well-Known Member
If you have a given amount of water in the air and the air warms up the RH% goes down. If the air cools RH% goes up. So heating the air, no matter how you do it, lowers the RH%. Thats why it's "relative" humidity. It's all about how much humidity the air can hold at a given temperature.
 

mordynyc

Well-Known Member
If you have a given amount of water in the air and the air warms up the RH% goes down. If the air cools RH% goes up. So heating the air, no matter how you do it, lowers the RH%. Thats why it's "relative" humidity. It's all about how much humidity the air can hold at a given temperature.
Exactly heat is heat.

I just got a heat mat thermostat for 15 bux; I plug it in to a ceramic heater near intake, set probe in corner of tent in a cold garage, and set it to 80f .
Im using smart pots and trying to maintain 68f root zone using a meat probe to check.
I also have one of these https://www.amazon.com/gp/product/B00PAK245E/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 in a 2 gallon bucket home made floater with a cup, foam, and rubber band -helps with RH immensely.
Plastic containers would clearly stay warmer but I like the fact of not over watering and the added oxygen.
 
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