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!
I brewed last Saturday in my shop.
Shop is heated so that was no problem. I've brewed in the cold several times.
I had planned to leave the water running slowly to prevent the line from freezing. It got turned off and froze in about 10 minutes. Realized it in time that shaking the line broke it up and started it flowing again.