Hearth Terms

A primer on fire and comfort appliances

Hearth:  The hearth industry includes all forms of manufacturing, service, design, and installation relating to fireplaces and stoves.  From tile stoves produced by artisans in Europe, to sculpted, steel stoves designed by architects, fire technology has advanced far beyond the traditional brick fireplace of Rockwell paintings and Christmas cards. 

Heating and comfort systems may include fireplaces, wood stoves, gas logs, and appliances, pellet stoves, barbecue grills, wood burning central systems, chimney sweeping, and any accessory associated with these systems.

BTU:  A measurement of heat produced by a stove, furnace, or fireplace.  In scientific terms, it is defined as the quantity of energy necessary to raise the temperature of one pound of water one degree Fahrenheit.

R-value: The higher the R-Value, the better the insulating properties. R-Values are most often used to express the thermal resistance (ability to stop heat flow) of a building wall, ceiling or floor. Because of this, most R-Values are calculated at normal temperatures of approx. 75 degrees Fahrenheit. R-Values are easy to add together so calculating the total R-Value of a wall is simply done by combining the values for the sheetrock, insulation, sheathing and siding.

K-value:  K-value is a measure of heat conductivity of a particular material. Specifically, it is the measure of the amount of heat, in BTUs per hour, that will be transmitted through one square foot of material that is one inch thick to cause a temperature change of one degree Fahrenheit from one side of the material to the other. The lower the K-value for a material, the better it insulates. If the K-value of the material is known, the R-value per inch can be determined by dividing 1 by the K-value (R-value per inch = 1/K value). The LOWER a K-Value, the better it performs as an insulator.

NG (Natural Gas):  The composition of natural gas varies in different localities. However, it is always a colorless, highly flammable gas consisting primarily of methane. Methane usually makes up from 80% to 95% of its volume. The balance is composed of varying amounts of methane, another hydrocarbon compound, and other gases such as carbon dioxide, nitrogen, helium, argon, hydrogen, and carbon monoxide.

LPG (Liquefied Petroleum Gas):  The primary source of LPG is "wet" natural gas. Wet natural gas contains impurities and heavier hydrocarbons, such as propane and butane. To turn wet natural gas into a "dry" gas, these heavier hydrocarbons and impurities must be removed. This extraction is called distilling.

More information on hearths