At this time of year, the big challenge of living off-grid in an earth-sheltered (read: 3 feet of insulation on 3 sides) is to remind yourself 69 on the thermostat would be T-shirt weather if it were describing the temperature outdoors, but when the only thing reflecting light back at you as you let the cat in at 5AM for his morning nap is the frost coating the world outside your door, it’s hard to remember that it’s too early in the year to light a fire.