How It Works
A natural gas or propane fireplace provides the warmth and distinctive
beauty of a natural fireplace without the mess associated with wood, pellets or
coal. Gas fireplaces come in three basic configurations: natural vent, direct
vent and vent free.
In a natural vent fireplace, the
chimney is combined with a double wall pipe - known as a B-vent flue - which runs
from the fireplace to the exterior of the home. Some models use a firebox or fireplace insert inside the larger fireplace to retain
more heat and reduce energy cost.
vent fireplaces draw air from outside and return exhaust outdoors with a
flue system. Vents leading to the outdoors can be installed behind the
fireplace so there’s no need for a chimney. This tightly sealed design only
uses air from the outside for superior energy efficiency. The airtight system
also works to prevent harmful emissions from entering the room.
fireplaces are the easiest to install and operate; they vent exhaust
straight into the room so there’s no need for a chimney or direct vent system.
However, the main disadvantage of this type of fireplace
is the potential for carbon monoxide (CO) buildup in the air. Excess CO
can be seriously or fatally harmful if the person affected is not removed to an
area with normal oxygen and CO content in the air. To minimize this danger, vent-free
systems have an oxygen-detection feature that shuts the fuel gas off when the
room’s oxygen level becomes hazardous.
What Can Go Wrong?
Many gas fireplaces use a small blower to move air and
improve heating efficiency. These blowers are
powered by motors that can fail over time.
Gas fireplaces burn cleaner and more efficiently than
wood-burning fireplaces, operating between 12,000 and 60,000 British Thermal
Units per hour (BTUh). Depending on usage and energy efficiency,
they can produce hundreds of pounds of carbon dioxide (CO2)