Greenhouse: greenhouse heaters, 1 by sal522

sal522 wrote:
I live in zone 5b. I have a portable greenhouse-the GronHaus- about 6x8x 7' high. Last winter I used space heaters meant for indoors and that was a bad idea, I went through a lot of them but somehow most of my plants survived even when temps. dropped below freezing a couple times.

Could someone please recommend the correct heater to use. Whenever I look I'm overwhelmed by the calculations they want. I don't know the the r-value of the material or how many BTU's I need.

Any help would be appreciated, thanks.