The heater you see below is a direct vent heater designed to heat a space up to 500 square feet in size. The tiny-tower is less than 100 square feet, including the loft, so I will likely be able to roast away in here this winter. Especially with this fluffy cotton-based fiberglass bat insulation I'm installing. It is 70% efficient and uses propane gas. The insulation was on-hand left-overs from the workshop insulation so it might as well be used, although not the best insulation in the world, it is easily accessible. The heater will be replaced with a rocket stove mass heater in the spring. The trap door provides access to the bays beneath the floor for storage of important accessories like batteries for the solar panel kit we will be installing, without taking up precious real estate. The floor has been insulated with 2" foam board and topped with pine, which I will finish with linseed oil. Enjoy photos below.