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, ventless gas fireplaces are much less expensive to install compared to traditional gas or wood fireplaces. Ventless gas fireplaces or heaters uses natural gas or propane as fuel and burns the gas with air from the room.

Some people install ventless gas fireplaces to add an alternate source of heat to thier 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 you need is a line to deliver propane from a tank or natural gas from your city's supply, so these are gaining in popularity.

To choose from among the different types of ventless gas fireplaces, consider how you will primarily use it. Each has a rating to tell you how much energy they consume and how much heat, measured in BTUs, they provide. Pay closest attention to the BTUs, because this figure will determine how large the room must be for the fireplace to function properly. Do not install a high-output fireplace in a small room, thinking that you will receive 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 chimneyless technology, so they vent out into the room. That's why the volume of air in a room is very important. Ventless gas fireplaces may take the place of central heating if your electricity 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 ventless gas fireplaces because of health concerns. Canada, Massachusetts, and California don't allow people to install these types of heaters because of their potential to build up carbon monoxide, deplete oxygen, and lead to unconsciousness or even suffocation. Check with your local building code before purchasing one of these appliances.

A milder health hazard offers another disadvantage to this choice. Ventless gas fireplaces lead to an increase in the room's humidity. Burning gas or propane creates water vapor that can build up in a room and possibly lead to mold and mildew growth. If most forms of mold aren't truly dangerous, they will certainly increase allergies and could spoil fabric, photographs, and books.