Thanks for that! I'd love to hear these guys thoughts.
I've actually been reading all relevant posts on this forum and have learned quite a bit from both of their previous posts!
Now that I've learned quite a bit I can ask better questions. It sounds like insulating my slab is a must, especially if I want to keep warm temperatures inside my greenhouse in our cold winters. I wont be running radiant heating, but I'll put insulated foam board under the slab and around the sides. I'm curious how this will look on the sides once finished though. I don't like the idea of having insulation showing on the visible slab (likely a couple inches shown on the front, and several inches along the back since the greenhouse will sit on a slightly angled part of my yard). Does the insulation only come up to the ground level? If so, aren't we still losing heat from the slab where the slab is exposed to the outside ambient air?
Here's my plan right now:
Through ACF I'll purchase a GrowMore GM16 greenhouse
- It has 10mm triple wall poly
- Insulate the interior north side of the greenhouse with bubble wrap in late fall through spring
- Insulate the slab
- Heat using a natural gas vented heater (HotDawg HD45 - 45,000 BTU Heater)
Questions:
1) Details on insulating the edges (per above description) would be appreciated!
2) I'm trying to get a rough gauge of what energy costs will be to keep my greenhouse warm, so I used an online calculator (results below). I'm pretty encouraged by it, since it seems quite affordable relative to the joy I'll get out of having a greenhouse to step into during the cold drab chicago winters.
Screenshot of the calculator results below, but here's a summary:
- I'll use 6,728 cubic feet of natural gas (~70 therms) each of the 3 coldest months of winter in my area. For me this equates to about $140/month for those cold months.
- This factors in my location, greenhouse wall materials, etc.
- The other 9 months are significatly warmer and will require less or zero gas.
