How warm can you keep a shed style greenhouse like this if you insulate the walls? Assuming it has power, could a small heater keep this space around 60 in the winter? I am running out of space and wondering if I can move my basement set up with grow lights outside . . .
by Satsuki_chan421
8 Comments
It depends on:
– size of shed
– size of heater
– winter temps in your area
– how air tight the shed is
I have a 12’x20′ shed that’s fully insulated with power that I can keep very very warm with a space heater. It’s controlled with a rainbird temperature controller. I was able to run grow lights, fan and heat. There were times (cold) however the pull was too much and the breaker would pop.
Yes this is commonly done with no problem. Its just a matter of electricity costs. I’d use oil filled heaters and circulate the air continuously with fans.
Shrink the volume of the shed to match your needs. If you are adding light, maximize the sunlight available. I use a combination of solid and bubble wrap type insulation to help as much as possible. -30 in my area.
Given enough heater (and heating cost), anything is doable. I don’t know what “small” means in your thinking of ‘small heater’ though.
I have a 12×40 insulated shed (about 5700 cubed ft), with a concrete slab floor. It can reach freezing inside if temps outside stay below freezing for more than two days and it’s not particularly sunny. I have six 240v overhead infrared heat panels, which are expensive to use (kWh) but I turn them on when necessary. That mainly fights off the freezing temps.
BUT, I do have a grow tent and one of those cheesy greenhouse racks in there too. By putting down a 2″ foam panel under them, having heating mats (my grow tent is 2×4, and I have a 2×4 heating mat at the base), plus the growlights, in those sealed little zipper boxes … I can keep the temps in the tents at 50+ F degrees while the shed is in high 30s and outside is 10F or lower (we get to -20F here as worst case).
So think about your shed as outer envelope, and don’t try to heat it all to target temp. Using grow tents within it, you can more efficiently localize the heat to where the plants are at and not have to make the whole shed up to your ideal minimum temp.
Getting to and maintaining heat is going to the issue, once an ambient temp is achieved it is easier hold,
And air circulation is your friend one fan high to push the warm air down and the other to move it back towards the other fan
If you’re using electricity, price out a small mini split heat pump for greater efficiency and utility costs.
Small heat pump should do it with minimal interaction (like loading a woodstove or refiring a pilot)