• Appliance - A solid or fossil fuel burning stove, fireplace, furnace, boiler, water heater, heater or cook stove.​

  • Ash - Noncombustible solid byproduct of solid fuel combustion.


  • B-Vent Fireplace - B Vent gas fireplaces use air from inside your home to fuel combustion and rely on the buoyancy of hot gases to vent exhaust through dedicated pipe systems.

  • Baffle - An obstructing device or partition in a wood burning appliance, used to direct the flow of gases and heat.

  • Blower - An electric, motor-driven fan used to circulate air at an increased pace and velocity through the fireplace convection air chamber.

  • BTU (British Thermal Unit) - A unit for measuring energy, equal to the amount of energy needed to increase the temperature of 1 pound of water by 1 degree Fahrenheit.

  • Burn Rate - Combustion rate, usually expressed in pounds of fuel consumed per hour.


  • Cap - Also called termination or chimney cap.  Covering for factory-built chimney that minimizes the effect of wind, and prevents entry of rain, snow, and debris into the chase.

  • Carbon Dioxide (CO2) - Colorless, odorless noncombustible gas produced by the complete combustion of carbonaceous fuel; is nontoxic.

  • Carbon Monoxide (CO) - Colorless, odorless, combustible, and toxic gas produced by the incomplete combustion of carbonaceous fuel.

  • Chase - A structure built around, and enclosing, portions of chimney exterior to the house.

  • Circulating Fireplace - A fireplace with multiple-wall construction around the fire chamber which permits air to circulate between the walls, become heated, and enter the house directly.

  • Clearances - Minimum distance, composed only of an air space, which must be maintained between a heat source such as a fireplace or vent and combustible surfaces.

  • Combustible Material - Material made of or surfaced with, wood, compressed paper, plant fibers, or other material that will ignite and burn, as applied to materials adjacent to or in contact with heat-producing appliances.

  • Convective Heating - The natural movement of air as it heats up and expands. This creates a natural flow of air as the warmer air moves upward and is replaced by cooler air.


  • Damper - Movable plate that directs the flow of gases and air in a solid fuel appliance or chimney connector.  In fireplaces, a pivoted metal plate, set just above the firebox, primarily used to close off the chimney when not in use. 

  • Direct Vent - Method of venting appliance whereby all air for combustion is derived directly from the outside atmosphere and all flue gases are discharged directly to the outside atmosphere. No chimney required.


  • Efficiency - The percentage of heat that goes into the room instead of up the chimney.


  • Factory-Built Fireplace - Prefabricated metal fire chamber and its chimney, commonly called “zero clearance.” Consists of listed manufactured components that are assembled in accordance with the terms of the listing to form the completed fireplace.

  • Firebox - The inner most compartment of a fireplace designed to support the combustion of fuel.

  • Fireplace Inserts - Solid fuel appliance designed to be installed partially or fully in the fire chamber of an existing masonry fireplace, and that vents into the fireplace chimney by means of full relining or appliance to flue methods.

  • Flashing - A metal device that covers a factory-built chimney roof penetration and helps stabilize the chimney.

  • Flexible Chimney Liner Listed, factory-built, double walled, continuous, flexible metal pipe for venting gas appliances. Used strictly within masonry or factory built chimneys to vent flue gases vertically to the outdoors.

  • Flue The passageway in a chimney for conveying flue gases to the outside atmosphere.

  • Furnace - A central heating appliance that supplies hot air, through ducts, to the house.


  • Gas Insert A gas appliance designed to be installed within an existing masonry fireplace opening or a metal factory-built firebox. It offers superior efficiency.

  • Gas Logs - An open flame type appliance consisting of a burner and metal pan or base supporting simulated logs.  May also include various ember media.

  • Gas Vent A factory made, listed venting system designed to remove flue gases to the outside atmosphere.


  • Hearth The surface under and/or in front of your stove or fireplace, often made of brick, or tile.

  • Hip Roof - A roof that rises by inclined planes from all four sides of a building.


  • Linear A widescreen format fireplace.

  • Liquefied Petroleum Gas Colorless, odorless, and non-toxic gas separated from wet natural gas, light crude oil, and oil refinery gases.


  • Mantel - Shelf over and above the fireplace opening. Stone, brick or wood may be used.


  • Natural Gas Clean-burning fossil fuel available in vast quantities throughout North America and delivered to homes via an extensive pipeline network.

  • Noncombustible - A material that, when used properly, will not ignite, burn, support combustion, or release flammable vapors when subjected to heat.


  • Odorant - Material added to natural gas or propane in small amounts to create a detectable distinct odor.


  • Pilot Light  A small flame used to ignite the gas at the main burner.

  • Pressure Test  - Method of checking for leaks in the gas supply line prior to installation of appliances.

  • Propane A colorless, odorless, nontoxic LPG containing more heat value than natural gas.

  • PSI - Pounds of pressure per square inch.


  • Radiant Heat - Heat that moves out in waves from a central point and heats objects in its path. The invisible and harmless radiation emitted by a hot object. This radiation is converted into heat when it is absorbed.

  • Reduced Clearance (RC)  - RC backing plates are larger and ease installation when replacing a wood or gas fireplace with tighter framing dimensions.

  • Remote Control - A wireless handheld remote control system which allows the user complete control of the fire from anywhere in the room.


  • Safety Shutoff - A device, powered by a thermocouple, designed to shut off the gas supply to the pilot and or main burner if the source of ignition fails.

  • Secondary Air Combustion air directed downstream of the primary combustion zone (but still in the appliance) to support the combustion of remaining combustible gases; does not directly influence the rate of primary combustion.

  • Soot - Soft, black or brown, velvety deposit of carbon particles inside appliances, chimneys, and connectors.

  • Steady State Efficiency  - The ratio of the heat or BTU output vs. the heat or BTU input under steady conditions.

  • Storm Collar - Metal plate or collar fastened and sealed with high temp. sealant around the chimney just above the roof flashing. Prevents water from entering the space between the chimney and the roof flashing.


  • Thermal Efficiency - The percentage of heat, which is released in the fire, that gets through the appliance to become useful heat in the house.

  • Thermocouple  A device consisting of two pieces of dissimilar metals joined together at one end (hot junction). When the hot junction is heated, the thermocouple produces DC voltage across the other end. Used to power thermoelectric gas valves.

  • Thermostat An automatic device for regulating the temperature in a building by controlling the heating or cooling source. Acts strictly as an on/off switch - does not modulate the heating or cooling source.


  • Unvented  - Unvented or vent-free refers to the kind of hearth appliances that draws its combustion air from inside the home and is designed to burn so efficiently that it eliminates the need for venting.


  • Zero Clearance Fireplace Factory built units for installation into combustible construction.