HELPFUL TIP Did you know furnaces can get asthma? Carbon deposits can wreak havoc on efficiency, so have your furnace burners cleaned every 1-2 years. > More Tips   HEATING TERMS A-coil - The part of the air conditioner that is located inside the air handler. Its primary function is to absorb the heat from the air in your house. Boiler - A vessel in which water is heated. Used in traditional hot water heating systems and for radiant heat systems. Some old boilers look like a giant octopus F.Y.I. BTU - A British Thermal Unit is the amount of heat required to raise the temperature of one pound of water, one degree Fahrenheit. And you are correct has nothing to do with steeping tea or thermal underwear. Fan recycler - Electronic device that turns the furnace blower on and off in timed increments. Increases the furnace’s efficiency. Recycling is good. Flue - A flue exhausts byproducts of combustion (such as water vapor and carbon dioxide) to the outside. You can’t catch this type of flue when someone sneezes. Forced air ventilation - A type of heating system that uses a blower motor to move air through the furnace and into the ductwork. Don’t worry the air is gently forced. Heat exchanger - Located in the furnace, the heat exchanger transfers heat to the surrounding air, which is then pumped throughout the home. Heat Loss - The amount of heat lost, measured in BTU's, from a space to be conditioned, at the local winter outdoor design temperature and a specified indoor design condition. Preferred over hair loss. LP Conversion - A kit that allows a furnace to be converted to use LP instead of natural gas. Manual/Auto zone duct - Zone ducts separate trunk lines to each floor or zone. Thermostats in each zone control electronic zone dampers. Manual ones are operated by hand and must be adjusted seasonally. Plenum - Airflow passage made of duct board, metal, drywall, or wood. Joins supply and return ducts with HVAC equipment. Genz-Ryan makes all plenums of metal. Radiant floor heating - Radiant floors circulate warm water through PEX tubing embedded in the floor of your home. The heat radiates up through the floor, warming the people, furnishings and air in the room. The warmth stays down around where the people are, not up at the ceiling or lost to the outdoors every time a door or window is opened. Return air - Air drawn into a heating unit after its been circulated from the heater's output supply to a room. Also known as “Please come back air.” Secondary heat exchanger - Another heat exchanger for furnaces with 90% or greater efficiency. This allows more heat to be sent into the house instead of escaping out the flue. Set-back thermostat - A thermometer that can be programmed to change the temperature in the house automatically. Transite heating - Underground PVC pipe that carries heat to basement. Variable speed furnace blower - A variable-speed air-handling device for moving air in a distribution system. Volume damper - A device that is located in ductwork to adjust air flow. The movable plate opens and closes to control airflow. Dampers are used effectively in zoning to regulate airflow to certain rooms. There are basically two types of dampers: manual and motorized. A manual damper generally consists of a sheet metal (or similar material) flap, shaped to fit the inside of a round or rectangular duct. By rotating a handle located outside of the duct a technician can adjust (see Balancing) air flow to match the needs of a particular area or room. A motorized damper is generally used in a zoned system (see Zoning) to automatically deliver conditioned air to specific rooms or zones. Warm-air plenum - Plenum that takes air from a furnace and moves it into the duct system to circulate through the house. The air conditioner coil may be located inside this plenum. Zoned system - A method of partitioning a home into independently controlled comfort zones for enhanced comfort and efficiency. A zone is the area that one thermostat is controlling. For example: A two-story house with a thermostat on each floor has two zones, one for each floor. Zone Control Systems eliminate "hot and cold spots" and can help save energy. A Zone Control System splits your house into areas with common heating and cooling requirements, and puts every "zone" under the control of its own thermostat. Each zone is effectively heated or cooled independently of the others. A system of electronically controlled dampers directs heated or cooled air to where it is needed -- reducing energy bills as much as 30%. Now you can zone out.