Actually its all a semi-sealed system, none of the joints are sealed up but the burner actually draws it's air from down below, and there is a tube coming through the floor and coming up to the bottom of the stove to supply cold air from outside. A carbon sensor wouldnt be a bad plan, really any enclosed space for occupation should have them. Since it will usually have electrical hookup, it will really be easiest and cheapest to run an electric heater when its convenient. I will say the LP stove isn't overly efficient, but it is leaps and bounds better than the old broken kerosene thing. Really it's about the same as a gas furnace once I figure some things out to make it more efficient. We use a wood stove to heat the house, when done right its darn efficient!