We are expecting an air temp tonight of -30-35 with wind chills in the -60-70 degree range tonight. I worked on one of my cars in my heated shop this afternoon with the gas furnace set at 55 degrees. I was comfortable with a light jacket and cap on. The furnace ran about every 45 minutes. I'm sure glad my contractor advised me to super insulate with foam insulation in the walls and double insulation in the ceiling and attic. We also put in the highest grade overhead garage doors which also have insulated glass windows. I doubt that heating my shop without these upgrades would have been practical. This shop was many years in planning and it has already proven to be my Winter sanctuary as I am now retired. So by Spring/May I will have everything buffed, polished, tweaked, tightened, adjusted, upgraded, modified, painted, lubed, inflated, deflated, jacked up, jacked down and ready for Spring!