Vented or Ventfree? Which fireplace is right for your family? Hearth Tips Fran Marengo Jan 05 2016 Vented or Ventfree? Which fireplace is right for your family? We offer both kinds; each has unique advantages and disadvantages. Vented Unvented 1. All exhaust fumes (including odors and moisture) are taken out of the home. 1. Unvented fireplaces burn very clean but not perfect, much like a kerosene heater. Measurable levels of carbon monoxide and other chemicals such as nitrogen dioxide (an irritant to eyes, nose and throat) vent into the home. Some people are more sensitive to this than others. Odor is usually noticable by those with a strong sense of smell. 2. Some vented models ("direct-vent" types) are excellent heaters having efficiency ratings up to 80% plus. Others are meant primarily for "looks" and have low efficiencies. Consumers must be sure to choose a model that suits their priorities. 2. All unvented models are good heaters. since the heat cannot escape up a chimney. However, labeling on the permanent metal tags attached to the unit (as of 3/96 not required to be stated in advertising literature), used to state that a window must be opened "an inch or two" when using heater. This statement was replaced a few years ago with, "Consult your installation manual for ventilation requirements." All manuals now advise that if you do not have enough cubic feet of space as compared to the amount of BTU's, you should cut a permanent hole in the outside wall of your house a install louver in it. 3. Very natural, realistic dancing flame patterns are possible. Some models meant mainly for "looks" allow rearranging and customizing of log positions for the ultimate in realism. 3. To burn as clean as possible, flames patterns tend to be noticably less realistic. Logs are placed only as per manufacturer's instructions and cannot be safely rearranged. 4. Vented models and their installation usually cost more than most unvented models. 4. Unvented models and their installation usually cost less than most vented models. 5. When considering adding a vented fireplace to the lower level of a two level home, it may be difficult to find a convenient place to run the venting. 5. Sometimes the only possible way to add a fireplace to the lower level of an existing two level home is to use an unvented model. 6. In a very tight house, direct-vent fireplace is often the method of choice. It pulls in air to feed the fire between the two layers of double vent pipe, and all exhaust is sent out through the center pipe. No heated room air can escape. 6. In an very tight house, unless a window is opened during use, an unvented fireplace can cause "indoor air pollution" consisting of traces of carbon monoxide, and various other chemicals plus large quantities of water vapor. Water vapor can form a "film" and encourage the growth of mold and mildew.