Not everyone speaks the same language. Understand all the terms related to natural gas heating and water heating systems.

A tube or conduit moving air from one place to another.

Valve, either manual or automatic, to remove air from the highest point of a coil or piping assembly.

The ratio of annual output of useful energy or heat to the annual energy input to the furnace or boiler. The higher the AFUE, the more efficient the equipment and the higher the efficiency the more savings on fuel bills.

The process of adjusting the flow of air in duct systems or water flow in hot-water heating systems. Proper balancing is performed using accurate instrumentation to deliver the right amount of heating or cooling to each area or room of the house.

The quantity of heat required to raise the temperature of a pound of water 1 degree from 59 degrees to 60 degrees. BTUH stands for British Thermal Unit Per Hour — this establishes a time reference to BTU input or output rates.

The rate at which a (heating) system maximizes fuel use. This rate is numerically described as a ratio called AFUE. As of January 1992, no furnaces can be manufactured with efficiencies lower that 78% AFUE. Boilers cannot be manufactured with efficiencies lower than 74% AFUE.

A heat exchanger transfers heat from combustion gases to the air blowing through the ductwork. It is vital that none of the combustion gas itself gets into the air stream. The primary heat exchanger handles the hottest gases.

Calculation to determine house btu heat loss; factors include conduction through construction materials, air infiltration losses and the difference between actual or projected outside temperatures and desired temperatures inside the house. Used for determining necessary heat output from the heating appliance.

An indirect water heater circulates water through a heat exchanger in the boiler. This heated water then flows to an insulated storage tank. Because the boiler does not need to operate frequently, this system is more efficient than the tankless coil. In fact, when an indirect water heater is used with a highly efficient boiler, the combination may [..]