What is the difference between a forced air and natural draft furnace?
The difference is how the air to stoke the fire is brought in the firebox. Natural draft furnaces open a damper that allows air to draw in to the firebox directly from the outside. Forced air furnaces use blowers to blow air directly in to the firebox with more control then natural draft furnaces while also having the option of using variable speeds to better control your firebox burn rate. They also allow the furnace to burn hotter.
