Fireplaces emit a variety of potentially toxic substances including carbon dioxide and carbon monoxide. The vent free gas fireplace offers no venting capacity so byproducts released from the fireplace remain in the house. It should be noted that vent free or ventless fireplaces are also available in electric and propane models. Because of its popularity we will focus on the vent free gas fireplace.
With advancements in insulation efficiency and the improved methods in which it is installed and the new technologies applied to the exterior of new homes, today’s homes are airtight. If you add to this a vent free gas fireplace where do the toxic byproducts go? They are released directly into your home.
Vent free fireplaces are banned in some U.S. states and are not approved in Canada. They maybe promoted as easier to install or just as safe as other fireplaces, but I would recommend that you consider a direct vent fireplace. Equipped with a sealed firebox the direct vent fireplace is generally safer. It works by drawing in combustion air from the outdoors directly into the firebox through a pipe, while another pipe exhausts its combustion products to the outdoors. The sealed glass panel on the front is critical in maintaining the quality of the air in the home and providing high energy efficiency.