AFUE: (Annual fuel Utilization Efficiency) An official heat source measurement rating for fireplaces and wall heaters

ANSI: (American National Standards Institute) This organization is comprised of more than 900 companies, many of them specialists in fireplace installation and maintenance.

Ash Drawer: Container beneath the combustion chamber that catches and contains ashes until removal.

Ash Trap: Compartment below the hearth that catches and contains ashes until removal, usually in a true masonry fireplace.

B-Vent: A gas fireplace that draws air from inside the home through ports in the firebox itself. (Also referred to as Natural vent.)

Bellows: These are triangular shaped bags on a wooden frame with a nozzle at one end and two handles at the other end. They are used to aid combustion in wood burning fireplaces by pumping air into the flames.

BTUs: This is an abbreviation of British Thermal Units. It is a measurement used to describe the heating capacity of the fireplace or stove and is calculated according to how much heating s required to raise the temperature of one pound of water by one degree Fahrenheit. It is also used to calculate gas line size.

Carbon Dioxide: (CO2) This gas is produced from carbon units with sufficient oxygen and is a component of several types of natural gases.

Carbon Monoxide: (CO) An odorless, colorless, tasteless poisonous gas.

Catalytic Combustor: A device used on some wood burning stoves to reduce the temperature at which smoke is ignited.

Chase: A structure built around, and enclosing, potions of the chimney and in some cases, housing the appliance.

Chimney: The passageway where flue or vent gases and vapors can escape to the outside atmosphere.

Circulating Firebox: Firebox with slatted ventilation where fans can be installed for air circulation. These vents should not be covered.

Clearance: This is the distance between the stove, fireplace, or chimney to combustible materials needed by the building and fire code.

Cord: A stack of wood logs which measures 4 x 4 x 8 feet (128 cubic feet).

Creosote: A very flammable by-product of combustion that can build up within the chimney and ignite.

Damper: A device used to reduce or close the opening between the firebox and flue.

Direct Vent: An appliance that draws combustion air from outdoors and exhausts its combustion products to the outdoors eliminating the need for a standard chimney system. A glass panel in direct vent units is critical to keeping the combustion system sealed from the home, maintaining high efficiency and indoor air quality. These can be vented horizontally or vertically.

Electronic Ignition: Requires electricity to start the unit either 110 volt or battery.

Emission: Waste products caused by combustion which can sometimes be seen as smoke.

EPA Regulations: Government regulations of wood burning appliances mandating that products sold after July 1, 1992 emit no more than 4.1 grams of particulate matter per hour for catalytic-equipped units and no more than 7.5 grams for non-catalytic-equipped units.

Fire Box: The chamber of the fireplace or stove that contains the fire.

Firebacks: A thick cast iron plate that protects the masonry and mortar from the heat of the flames. These also retain heat very well, radiating it back into the room.

Fireplace Insert: This is an appliance (wood, gas or pellet) designed to fit or insert into your existing fireplace to make it efficient.

Firestop: As a chimney component, a plate that surrounds the vent pipe or chimney system as it passes through a floor or wood barrier. Also sometimes has a radiation shield built into it.

Flue: Small vent through which combustion waste is discharged.

Gas Log: Although a direct vent fireplace or stove is gas and has logs, typically a gas log is described as a log set kit installed into an open wood burning fireplace converting it to gas.

Grate: A cast iron or steel structure or frame that holds wood or coal in the firebox.

Hearth: The floor of the fireplace where the fire is built. It can also include or refer to the portion of that floor that extends into the room.

Heat Exchanger: A device within the fireplace or stove that exchanges cold air in the room with heat generated from the firebox.

High-Efficiency Wood-Burning Fireplace: This is an energy efficient wood burning appliance that is EPA approved that burns the gasses in the smoke giving long burn times and heating from 1,000 to 3,000 square feet.

Kindling: Thin strips of dry wood, which are easily ignited, used to start a fire.

Mantel: A protruding shelf above the fireplace.

National Fuel Gas Code: This is the standard for gas hearth installation standards.

ODS Oxygen Depletion Sensor: A safety device that activates the fire’s flame monitoring device in case excessive levels of CO2 (deadly carbon monoxide), are detected. This would reduce the levels of oxygen, causing the pilot flame to become unstable and lift off the thermocouple tip. The fire then turns off automatically before the situation becomes dangerous.

Pilot Light: A small gas flame that ignites the main burner to produce fire in the gas fireplace.

Safety Pilots: This is a safety shutoff for gas flow, consisting of three components that includes the thermocouple, electromagnetic power unit (EMU), and pilot assembly. Normally used on gas logs installed into a wood burning fireplace.

Seasoned Wood: This is a term referring to fire wood that has been allowed to dry before being burned. This drying process usually takes approximately 12 months but is advantageous as the wood burns easier. Burning dry wood also releases fewer by-products during combustion than freshly cut wood, which holds more than 20% moisture.

See-through Fireplace: A fireplace placed within the wall between 2 rooms and that is visible from both rooms.

Surround: the area along the top and sides surrounding the fireplace itself; it usually includes the mantel and hearth.

Therm: This is a unit of heating that is equal to 100,000 BTUs.

Vent-Free, Ventless, or Unvented: Uses room air for combustion then vents combustion byproducts back into the room.

Zero-Clearance: Factory built fireplaces that have been sufficiently insulated and sometimes air-cooled to enable them to be placed in direct contact with combustible materials such as walls and floors.