Just got my efm 520 hooked up and running today. The temps outside are just below 40, but this thing is running me out of the house. Wife is just smiling. I was liking the 63 inside temp. I have 2 water to air exchangers in my duct work, and let me say I'm impressed with how much heat is coming out, way warmer than with teh LP. I am set on 4 teeth, aparently that is as low as yoiu can go, and about 2 1/2 on air. Low temp set on 140 and high on 160. I have a plate exchanger in crawl space ready to hook into domestic water, maybe this week sometime.
I'm burning coal now, finally.