I have mine in a walkout unheated basement so it's the only heat there. I guess some heat will rise to the main floor but it's mainly to keep the basement warm where my office is located.
Hardly any here either, last year the deck was covered with them, we'd clear them and a few days later the deck was covered again. the neighbors' goats ate well last fall.
I ran ours dry watering my new lawn the other day. I ran the sprinkler all day moving it around, Now I just do a little at a time. It did recover fairly quick.