"Ventless" Gas Fireplace
 

I have a home that has a vented gas fireplace (large contraption on the exterior of my house where the fireplace is located), but have been visiting homes on the market where one had a "ventless" gas fireplace. Does anyone know anything about these? Where do the gas fumes go? Also, this gas fireplace didn't have a blower to blow the hot air into the room.

Never heard of these things except for the electrical "fake" fire type... if there is combustion, a vent will be needed...

Stay away from any gas heaters that do not have a vent. Even when they operate properly with no sign of carbon monoxide, they can fill your house with carbon dioxide many times the outdoor concentration. This disturbs the natural concentration of the air and is not healthy.

Ouch, would a builder put in a ventless gas fireplace because it's cheaper than a vented one?

I know what you mean about carbon dioxide. One can become asphyxiated if the % of oxygen in the air drops below normal.

Not carbon dioxide...
Carbon Monoxide....

jgarth,
No, again Carbon Dioxide. Its carbon monoxide that occurs when gas appliances do not function properly. But Carbon Dioxide is a product of all combustion. There is approximatly 340 parts per million concentration in the outside air. The use of a ventless gas heater in a well sealed home would increase this concentration many times over. This can still displace oxygen and get you sick and can possibly cause death in concentrations of 20,000 ppm.
When you read the instructions on ventless gas heaters, theres always instructions to provide plenty of fresh air because the lack of sufficient oxygen will cause carbon monoxide to form.

So it basically works like this:
Carbon dioxide is always being formed as a part of combustion. When a lot of it accumulates and sufficient oxygen still exists, then people can get ill just from that alone. But when the oxygen level is insufficient to support combustion properly, then thats where the more important danger lies and carbon monoxide forms.

I have a ventless gas fireplace in the condo I rent and I refuse to use it. Within minutes a strong gas smell permeates the house. I just cannot believe it is safe.