Gas Fireplace & Ventless Gas Fireplace Choices
Realism
If you are familiar with the gas logs of 20 to 25 years ago, don't quit reading just yet. Those older logs were very fake. The flames were not realistic and the logs themselves just didn't look right.
Today, there is a good chance that if you saw a high quality set of gas logs actually burning, you would very likely think they are real. The logs are extremely realistic. Several manufacturers even offer different wood species! Certain types of gas logs (vented) come with vermiculite and glass wool. When the gas flames lick around these items, they look exactly like glowing embers in a real wood fire. The display is dramatic. In fact, just eight days ago, I installed another set for a friend. We turned the logs on for the first time and my friend was absolutely amazed. You will be too!
The Two Types
Years ago, there was only one type of gas log, that being the vented type. These are still made today. However, energy conservation trends produced gas appliances that are vent free. This technology found its way into the U.S. gas log market not too long ago. The technology actually started in Europe many years ago.
The vented logs are those that require a working chimney. They produce vast amounts of heat (some up to 90,000 BTU's per hour.) But, since you must open the fireplace damper as if burning a wood fire, most of this heat escapes up the chimney (85 to 90 percent!)
Vented gas logs also produce massive amounts of carbon monoxide, a deadly, toxic gas. This carbon monoxide results from the low tech burner that is used to combust the gas. In most cases, the gas simply escapes from a simple pipe that has holes drilled into it. This pipe is usually covered with silica sand. The gas filters through the sand so that the entire area under the gas log set appears to be on fire.
Vent free gas logs are entirely different. They have specially designed burners that are not covered with anything. They are hidden underneath and behind the logs. These burners are adjusted so that enough air is supplied to the burner to combust the natural gas with top efficiency. This combustion process produces a minimum of carbon monoxide.
Furthermore, as an additional safety measure, to protect against the buildup of carbon monoxide in a confined space, vent free logs approved by the American Gas Association (AGA) are equipped with oxygen depletion sensors (ODS). These sensors can tell how much oxygen is left in the air near the bottom of your floor. As carbon monoxide starts to build up, it dilutes/depletes the amount of oxygen in the room(s) / confined space. This, in turn, activates the sensor and the gas shuts off to the logs. All of this happens long before you would feel the effects of carbon monoxide poisoning.
Because you cannot cover the burners of vent free logs with anything, you cannot experience the burning ember effect with these products. These logs are not as realistic as the vented gas logs.
Moisture Problem Potential
The burning of natural gas produces large quantities of water (1.5 gallons for every 100,00 BTU's of gas burned.) If you live in an area that heats with natural gas, just go outside on a cold winter's day and look at everyone's chimney. Do you see that white vapor or steam issuing out from all the chimneys? That is the water vapor that is produced inside of everyone's furnace or hot water heater.
This same thing happens when you ignite your gas log set. If you have a vented set, this vapor travels up the chimney just like that of your furnace or hot water heater. In certain instances (when the gas logs are burning on low), you may have a slight problem. If your chimney is extremely cold, this water vapor might condense and run back down your chimney. When the logs are burning with more intensity, this is usually not a problem, as the flue gets nice and warm.
Vent free logs, on the other hand, can sometimes create massive problems with regard to this moisture. Since the logs do not vent to the outside, all of this moisture is trapped inside your house. Condensation can develop on cold surfaces. If this happens in an area you cannot see (attic, inside exterior walls, etc.), you may begin to experience problems. However, some people who heat with radiators may desire and need this extra humidity in their homes. You will have to judge for yourself.
Safety Issues
If you are not proficient at working with natural gas, by all means have a professional install your gas logs. Also, if you purchase a vented set of gas logs, have your existing chimney cleaned by a professional chimney sweep. The heat and moisture from the gas logs can cause major staining problems with the soot and creosote buildup in wood burning chimneys.
If you purchase a vented set of logs, be sure to fix your fireplace damper in the open position with a clamp. If you fail to do this, carbon monoxide cannot escape out the chimney! With wood fires, you know quickly that a damper is closed because of smoke buildup. This will NOT happen with your gas logs!
Give serious consideration to purchasing a carbon monoxide detector no matter which type of gas log you buy. It's better to be safe than sorry.