Direct vent gas fireplaces are the most popular hearth systems today. It makes sense, because they are convenient and safe, featuring sealed combustion systems that protect indoor air quality by drawing outside air for the fire and expelling 100% of combustion exhaust and byproducts outside the home. Venting includes a single “direct vent” with two chambers that work together to perform dual purposes: one chamber draws oxygen from outside, while another expels the fire’s byproducts and gases. Most direct vents are terminated horizontally through a wall, but they can also be routed through a top vent or side vent.