We choose not to sell Vent-less or Vent-Free Gas Product. It is our opinion that with a vent-less product the room is used as a chimney. Carbon Monoxide (CO) and water are by-products of gas combustion. In the homes in our area that are well insulated, these by-products can be detrimental. Condensation of water and carbon build up on walls, furniture and ceilings are possible with a vent-less product. People with allergies or respiratory problems, pregnant women and elderly people are warned about exposure to these products in the product manuals.