The latest trend in fireplaces is the vent free gas log. Manufacturers market these logs based on their high burning efficiency of 92 to 99 percent and their ability to burn without requiring ventilation. Many people buy into these impressive features, thinking they will never need to open the flue again. However, those same features also come with many downsides that could be dangerous to your health.
Vent free gas logs burn natural gas fuel and do not require any ventilation. The fire utilizes the oxygen inside the home instead of drawing it down through the chimney like traditional fireplaces. The logs are specially made to burn without any venting and should not be replaced by any other types of logs in a vent free system.
The nearly perfect efficiency has to be as high as it is because otherwise too many people would fall ill from using the vent free gas logs. The one to eight percent of unburned fuel still creates harmful materials, like carbon monoxide, which can be lethal in high enough concentrations. Vent free fires do not offer any escape for these dangerous fumes, so they build up inside the house to be inhaled by all the inhabitants. Many people actually complain of aggravated asthma, allergies and other respiratory troubles upon using a vent free set up.
Another issue with vent free units is the excessive build up of water vapor. Fires create water vapor and if it has nowhere to go, it condenses on walls, floors and furniture. This leaves the home humid, uncomfortable, and open to the growth of mold. At the very least, the walls and furniture will suffer from water damage.
The vent free gas logs should not serve as a source of heat. While marketing suggests they produce high amounts of heat, that heat cannot be sustained because the fire should not stay on for more than a few hours at a time. To burn a fire any longer could deplete oxygen levels in the house and inflate fume levels and humidity. At this point, the fire would require some kind of ventilation, like opening a window, in order to continue safely, and this defeats the idea of having a vent free system.
Many newer houses have an airtight build, which can interfere with the combustion process too. If air does not regularly enter the home, then the fire will quickly use up any excess oxygen in the home. At that point, the fire burns out unless a window is opened to allow more oxygen to enter. Again, this nulls the point of a vent free fire.
While vent free gas logs sound impressive and ideal on paper, the truth is that they present more issues than they are worth. Instead of investing money into an unhealthy insert like this, look into a high efficiency traditional fireplace or a direct vent unit. If you live in the Louisville area, contact All American Chimney Service, LLC for more information on your fireplace options.