Ventless gas fireplaces are controversial but potentially beneficial sources of heat for a single room. Since they do not require a flue, chimney, or external venting ducts, they are much less expensive to install compared to traditional gas or wood fireplaces. Ventless fireplaces or heaters uses natural gas or propane as fuel and burns the gas with air from the room.
Some people install this type of fireplace to add an alternate source of heat to their homes, such as in a bedroom that gets especially chilly. Of course, the fireplace can also bring a cozy, decorative element to a corner, as they are available in many colors and styles. All that a homeowner needs is a line to deliver propane from a tank or a natural gas pipeline into the home, so they are gaining in popularity.
To choose from among the different types of ventless gas fireplaces, a homeowner should consider how he will primarily use it. Each has a rating for how much energy they consume and how much heat, measured in BTUs, they provide. Consumers should pay closest attention to the BTUs, because this figure will determine how large the room can be for the fireplace to function properly. A high-output fireplace should not be installed in a small room for the purpose of generating more heat.
All kinds of combustion, whether gas or wood, requires the oxygen in air to create flames. Therefore, no fire could ever be truly "ventless," or it would extinguish itself. Ventless gas fireplaces are really using ductless or chimney-less technology, so they vent out into the room. That's why the volume of air in a room is very important. These fireplaces may take the place of central heating if the electricity in a home ever goes out, but most manufacturers recommend only using such a fireplace as a secondary source of heat.
Several states within the United States, as well as other countries, have completely outlawed such fireplaces because of health concerns. Canada, Massachusetts, and California don't allow people to install them because they could cause a build up carbon monoxide in a room, deplete the oxygen, and cause unconsciousness or even suffocate individuals in the room. Homeowners should check their local building codes before purchasing one of these appliances and make sure that they know how to use the device safely.
This type of fireplace also has other, milder health hazards. It can cause an increase in the room's humidity, for example, since burning gas or propane creates water vapor that can build up in a room. This may lead to mold and mildew growth, and although most forms of mold aren't truly dangerous, they will certainly increase allergies and could spoil fabric, photographs, and books.