AFUE
Annualized Fuel Utilization Efficiency is a measure of your furnace's heating efficiency. It is how well you system will convert fuel to energy. The higher the AFUE percentage, the more efficient the furnace. The minimum percentage established by the DOE for furnaces is 78%.
Air Balance
HVAC term for distributing air through a system to precisely match the required amount.
Air Infiltration
The unwanted entrance of air due to leakage, temperature difference, or wind.
Airflow
The distribution or movement of air. It is how energy is transferred using and forced air system
Air-Conditioning and Refrigeration Institute (ARI)
ARI is an industry trade association that develops standards for measuring and certifying product performance. For instance, ARI Standard 270 provides guidelines for establishing sound levels for outdoor air-conditioning equipment.
Air Handler/Coil Blower
The indoor part of an air conditioner or heat pump that moves cooled or heated air throughout the ductwork of your home. An air handler is usually a furnace or a blower coil.
Blower
In HVAC the device in an air conditioner that distributes the filtered air from the return duct over the coil/heat exchanger. This circulated air is cooled/heated and then sent through the supply duct, past dampers, and through supply diffusers to the living/working space.
Building Envelope
Elements of the building, including all external building materials, windows, and walls, that enclose the internal space.
Btu
A British thermal unit is a unit of heat energy. One Btu is the amount of heat required to raise one pound of water by one degree Fahrenheit. Equals 252 calories. The higher the Btu rating, the greater the heating capacity of the system.
CAE
The Combined Annual Efficiency is a measure of the amount of heat produced for every dollar of fuel consumed for both home and water heating.
Carbon Monoxide
An odorless, colorless, tasteless, poisonous and flammable gas that is produced when carbon burns with insufficient air.
Central Air Conditioning System
System in which air is treated at a central location and distributed to and from rooms by one or more fans and a series of ducts.
CFM
Stands for Cubic Feet per Minute. This measurement indicates how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being moved through the ductwork by the system.
Combustion
The process of burning; the oxidation of a material by applying heat, which unites oxygen with a material or fuel.
Combustion Air
Air that provides the necessary oxygen for complete, clean combustion and maximum heating value.
Compressor
The part of the outdoor air conditioner or heat pump that compresses and pumps refrigerant. Typically found outside the home.
Condenser Coil
The outdoor portion of an air conditioner or heat pump that aids in the energy transfer.
Damper
A movable plate, located in the ductwork, that regulates airflow. Dampers are used to direct air to the areas that need it most. Typically used in a zoning application.
dB
A decibel is a unit used to measure the relative intensity of sound.
DOE
The Department of Energy is a federal agency responsible for setting industry efficiency standards and monitoring the consumption of energy sources.
Dual Fuel (or Hybrid)
A comfort system that pairs an electric heat pump with a gas furnace, providing an energy-efficient alternative to the conventional furnace/air conditioner combination.
Ductwork
The method by which air is channeled from the furnace or the blower coil throughout your home.
Electronic Air Cleaner
An electronic device that filters out large particles and bioaerosols in indoor air.
ENERGY STAR®
An EPA (Environmental Protection Agency) designation attached to HVAC products that meet or exceed EPA guidelines for high-efficiency performance above the standard government minimums.
EPA
The Environmental Protection Agency develops and enforces federal environmental regulations. The EPA oversees the nationwide ENERGY STAR® program.
Evaporator Coil
The part of the air conditioner or heat pump that is located inside the air handler or attached to the furnace. Its primary function is to absorb energy from the air in your home..
Filter (air)
A device that removes contaminants, by mechanical filtration, from the fresh air stream before the air enters the living space. Filters can be installed as part of a heating/cooling system through which air flows for the purpose of removing particulates before or after the air enters the mechanical components.
Flue
The structure (in a residential heating appliance, industrial furnace, or power plant) into which combustion gases flow and are contained until they are emitted to the atmosphere.
FAQ
Stands for "frequently asked questions."
Garage Heaters (or unit heaters)
Garage heaters are an excellent product for combating cold garages and workshops during the winter months. Heating capacities provide warmth for a 1 car garage up to a 4+ car garage application. Separated combustion models provide heating for hard-to-heat applications. Available in natural or propane gas, units should be installed by a Lennox dealer/installer.
Heat Exchanger
Located in the furnace, the heat exchanger transfers heat to the surrounding air, which is then distributed throughout the home.
Heat Pump
A heat pump is an HVAC unit that heats or cools by transferring energy. During the winter, a heat pump draws energy from outdoor air and circulates it through your home's air ducts. In the summer, it reverses the process and removes energy from your house and releases it outdoors.
Horizontal Flow
When an air handler or furnace is positioned on its side and circulates air in one end and out the other. Ideal for attic or crawl space installations.
HSPF
The Heating Seasonal Performance Factor is the heating efficiency rating for heat pumps. The higher the rating, the more efficient the heat pump. HSPF will be regulated in 2007.7 The higher the HSPF the less energy it will take to operate the equipment.
Humidifier
An indoor air quality device that introduces moisture to air as it passes from the air handler into the ductwork for distribution throughout the home.
Humidistat
An automatic device used to maintain humidity at a fixed or adjustable set point.
HVAC
Heating, Ventilation and Air Conditioning.
Indoor Coil
See Evaporator Coil.
Indoor Air Pollutant
Particles and dust, fibers, mists, bioaerosols, and gases or vapors.
Infiltration
Air leakage inward through cracks and interstices and through ceilings, floors, and walls of a space or building.
MERV Rating
The MERV (Minimum Efficiency Reporting Value) rating of a filter describes the size of the holes in the filter that allow air to pass through. The higher the MERV rating, the smaller the holes in the filter, the higher the efficiency.
Micron
A unit of measure equal to one millionth of a meter, or one thousandth of a millimeter.
Natural Ventilation
In HVAC the movement of outdoor air into a space through intentionally provided openings, such as windows and doors, or through non-powered ventilators or by infiltration.
Negative Pressure
Condition that exists when less air is supplied to a space than is exhausted from the space, so the air pressure within that space is less than that in surrounding areas. Under this condition, if an opening exists, air will flow from surrounding areas into the negatively pressurized space.
Odors/Chemicals
Air contaminants in the form of gases.
Outdoor Coil
See Condenser Coil.
Pascal
A unit of measurement in determining overall pressure on ductwork of fans.
Particles
Any substances measuring less than 100 microns in diameter. The EPA has found that small particles (less than 2.5 microns) are responsible for the health effects of greatest concern.
Positive Pressure
Condition that exists when more air is supplied to a space than is exhausted, so the air pressure within that space is greater than that in surrounding areas. Under this condition, if an opening exists, air will flow from the positively pressurized space into surrounding areas.
Programmable Thermostat
A thermostat with the ability to record different temperature/time settings for your heating and/or cooling equipment.
Pressure, Static
In flowing air, the total pressure minus velocity pressure. The portion of the pressure that pushes equally in all directions inside ductwork or a room.
Preventative Maintenance
Regular and systematic inspection, cleaning, and replacement of worn parts, materials, and systems. Preventive maintenance helps to prevent parts, material, and systems failure by ensuring that parts, materials and systems are in good working order.
R-Value
A measure of the capacity of a material to resist heat transfer. The R-Value is the reciprocal of the conductivity of a material (U-Value). The larger the R-Value of a material, the greater its insulating properties.
R-410A Refrigerant
A chlorine-free refrigerant that meets the EPA's newest, most stringent environmental guidelines.
Refrigerant
The compound (working fluid) used in air conditioners, heat pumps, and refrigerators to transfer heat into or out of an interior space. This fluid boils at a very low temperature enabling it to evaporate and absorb heat.
Refrigerant Lines
Two copper lines that connect the outdoor air conditioner or heat pump to the indoor evaporator coil.
Relative Humidity
A measure of the percent of moisture actually in the air compared with what would be in it if it were fully saturated at that temperature. When the air is fully saturated, its relative humidity is 100 percent.
Return Air
Air that is returned to a heating or cooling appliance from a heated or cooled space.
Scroll Compressor
A specially designed compressor that works in a circular motion, as opposed to up-and-down piston action.
SEER
The Seasonal Energy Efficiency Ratio is an energy efficiency rating for air conditioners. The higher the SEER, the better the energy performance, the more you save. The DOE's established minimum SEER rating for cooling is 13.00. The higher the SEER the less expensive the unit is to operate.
Single Package System
A heating and cooling system contained in one outdoor unit.
Split System
An HVAC system in which some components are located inside the structure of the house and some are located outside. Split systems should be matched for optimal efficiency.
Stack Effect
The overall upward movement of air inside a building that results from heated air rising and escaping through openings in the building super structure, thus causing an indoor pressure level lower than that in the soil gas beneath or surrounding the building foundation.
Static Pressure
Condition that exists when an equal amount of air is supplied to and exhausted from a space. At static pressure, equilibrium has been reached.
Supply Duct
HVAC term for the duct(s) of a forced air heating/cooling system through which heated or cooled air is supplied to rooms by the action of the fan of the central heating or cooling unit.
Therm
A unit of heat containing 100,000 British thermal units(BTU).
Thermidistat
Monitors temperature and humidity and adjusts heating or cooling system to maintain desired levels.
Thermostat
Usually found on an inside wall, this device operates as a control to regulate your heating and cooling equipment, allowing you to adjust your home comfort at the touch of a switch.
Ton
Unit of measurement for determining cooling capacity. One ton equals 12,000 Btu.
Two-Stage Operation
Provides two levels of heating or cooling output for greater temperature control, energy efficiency and improved indoor air quality.
Up flow
When an air handler or furnace is installed in an upright position and circulates air through the side and bottom and out through the top. Typically used in basement, closet and attic installations.
Variable Speed Motor
A motor that automatically adjusts the flow of air based on the firing rate of the equipment.
Ventilator
A system that exchanges indoor air with outdoor air.
Ventilation
The process of moving air (changing) into and out of an interior space either by natural or mechanically induced (forced) means.
Ventilation Air
Defined as the total air, which is a combination of the air brought inside from outdoors and the air that is being re-circulated within the building. Sometimes, however, used in reference only to the air brought into the system from the outdoors; this document defines this air as "outdoor air ventilation."
Ventilation Rate
The rate at which indoor air enters and leaves a building. Expressed in one of two ways: the number of changes of outdoor air per unit of time (air changes per hour, or "ach") or the rate at which a volume of outdoor air enters per unit of time (cubic feet per minute, or "cfm").
Zone
In HVAC an area within the interior space of a building, such as an individual room(s), to be cooled, heated, or ventilated. A zone has its own thermostat to control the flow of conditioned air into the space.
Zoning
The combining of rooms in a structure according to similar heating and cooling patterns. Zoning requires using more than one thermostat to control heating, cooling, and ventilation equipment.
