I brewed two batches last saturday, it was 10 above. I ran the burner outside. I sat my MLT just inside the door. I shot about 5 degrees high, added my strike water to the MLT about a gallon at a time with a stock pot, stirred it until i hit the correct temp, then added the grist. I did all of my mash and runoff in the house. It was a bit of a drag but it was better then standing outside the whole time and loosing temps on the MLT. have fun!