As with any product, there are pros and cons associated with both vented and ventless gas logs. Most manufacturers recommend that gas logs be vented somehow so that your home is free of hazardous carbon monoxide fumes. However, it is possible for you to install a fireplace that uses ventless logs if you follow certain safety precautions. These logs have burners that produce a very high heat without any exhaust. For this reason, they can by used in your existing fireplace with the damper closed. On the opposite side, vented gas logs can only be used in fireplaces that have the damper open.
The most important advantage that you will get from ventless logs is that they produce a very high heat that stays in the room and is not expelled out through the chimney. They also use less gas than their vented cousins and are friendlier to the environment. But, they do have many disadvantages that you need to consider before purchasing them.
Vent free gas logs put excess moisture into the air which can ultimately cause mold and mildew to appear throughout your home. You must always be sure that you have fresh air circulating throughout the room when the logs are on. Otherwise, you run the risk of depleting the oxygen level in your home. Of course, by opening a window during a cold winter day counteracts the warming affect from the logs.
There are additional negative features that you should be aware of. Vent free logs tend to give off an odor resembling burning kerosene while they are burning. They also are illegal in some geographical areas and are often monitored and controlled by local building codes. The flame emitted by vent free logs is not near as realistic as the one given off by vented logs and it doesn’t actually look like a real fire is burning.
The bottom line is that ventless gas logs seem to be less popular among consumers than vented gas logs. Most manufacturers lean towards promoting and selling their vented logs because they are safer, quite energy efficient and give off a flame that looks like real wood is burning. As with any business, they are there to sell products that appeal to the most customers. Vented logs appear to fit snugly into this category.