I ran my S9 last year and it did just okay for a 20 foot section of my greenhouse double walled. Kept it above freezing the whole time but I was growing in the soil. I'm awaiting my S19 to arrive which I will try to heat the whole 40x12 foot greenhouse this year but I will be growing in pots on tables to elevate into the heat. Likely just put the miner under the tables. It's all experimenting for me now as I try to find what will work.

Here is my blog post where I set my S9 up in Feb.