Your definition of comfort may be different than your neighbor’s. Knowing the definitions of some of the most commonly used terminology when referring to heating and air conditioning will tell you what you need to know when discussing your new HVAC system with a WC home comfort specialist.

[A]  [B]  [C]  [D]  [E]   [G]  [H]  [I]   [M]  [O]  [P]  [R]  [S]  [T]  [U]  [V]  [Z] A

AFUE- Annual Fuel Utilization Efficiency. The formula for conversion of a gas furnace from fuel into energy.  The higher the rating, the more efficient the unit.

Air Handler - The indoor component that moves the heated or cool air throughout the duct work in your home.  An air handler is usually a blower coil or a furnace. 

B

BTU - British Thermal Unit.  The amount of energy needed to change the temperature of one pound of water by one degree Fahrenheit. In your home, this represents, the measure of heat given off when fuel is burned for heating or the measure of heat extracted from your home for cooling.

C

CAE - Combined Annual Efficiency.  The measurement of heat produced for every dollar of fuel consumed for both water and home heating.

Capacity - The output or producing ability of a piece of  heating or cooling equipment.  Heating and cooling capacities are referred to as BTU’s.

Carbon Monoxide - A poisonous, odorless, flammable gas produced when carbon burns with insufficient air.  This gas is deadly to humans.

CFM - Cubic Feet per Minute.  A standard measure of air flow.  A conventional  system requires 400 CFM per ton of air conditioning.  

Compressor - It is part of the outdoor unit and is the central point of a heat pump or air conditioning system.  The compressor pumps down the refrigerant into the condenser, coil, then out into the evaporator coil and back to be re-circulated. This cycle occurs to meet the cooling requirements of the system.

Condensing Unit - The outdoor component consisting of; compressor, condenser, coil and fan.  

Condenser Coil or Outdoor Coil - The coil is in the air conditioner and its function, is to release heat from the refrigerant.  The cooler outdoor air that passes through the coil condenses,  that is, changes the refrigerant from vapor to liquid. 

D

DB Decimal Level - Sound Level

Damper - A movable plate that opens and closes to control air flow.  Often times, dampers are used to balance airflow in a duct system.  They can also be used in a zone system to regulate airflow to different rooms.

DOE - The Department of Energy is a federal agency  responsible for establishing  industry efficiency standards and monitoring the consumption of energy sources.

Ductwork - Pipes that carry air throughout a home/office.  The performance of your HVAC  system is dependent upon these long cylinder like tubes to carry airflow. 

E

EAC Electronic Air Cleaner - A piece of equipment that filters out large particles and bioaerosols in indoor air.

Energy Star - A label used to identify that an HVAC system meets or exceeds the EPA guidelines for energy efficiency.

EPA - The Environmental Protection Agency. The EPA develops and enforces, federal environmental  regulations.  In addition, the EPA’s responsibility is to oversee the Energy Star Program nationwide.  

G

Gas Furnace Heat Exchanger - The heat exchanger transfers heat to eh surrounding air from the blower.  It is then circulated throughout the home.

H

Heat Pump - An HVAC unit that cools or heats by moving heat.  In the winter, a heat pump draws heat from outdoor air and circulates it through your home or office air duct system.  During the summer, it reverses the process and removes heat from your home or office and releases it outdoors.  

HSPF - Heating Seasonal Performance Factor. A rating used to measure the heat efficiency of a heat pump.  The higher the number, the more efficient the unit.

Humidifier - An indoor quality, piece of equipment, that deposits moisture to heated air as it passes from the furnace into the duct work to distribute throughout the home.  

Humidistat - An automatic device used to maintain the humidity at an adjustable or fixed set point.

HVAC - Heating Ventilation and Air Conditioning.

I

Indoor Coil or Evaporator Coil - This indoor coil will get cold as the blower from your furnace passes warm air across it, consequently cooling down the indoors.  The warm indoor air will evaporate the refrigerant from a liquid to a vapor. 

ISO 9000 - A unit of international standards for quality management and assurance.

M

MERV Rating - Minimum Efficiency Reporting Value. Used to rate a filter, describing the size of the holes in the filter that allows air to pass through.  The higher the MERV rating, the smaller the holes are in the filter and the higher the efficiency.

Micron - A unit of measure equal to one millionth of a meter, or one thousandth of a millimeter.  

O

Odors/Chemicals - Air contaminants in the form of gases.

P

Package Unit - A cooling and heating system that come together in one package.

Particles - Any substances measuring less than 100 microns in diameter.  According to the EPA, small particles that are smaller than 2.5 microns cause the greatest health concern.

Programmable Thermostat - A thermostat that has the ability to record different temperatures and time settings for a heating and cooling system.

R

Refrigerant - What consumers refer to as Freon or Puron.  The fluid and gas that evaporates and condenses throughout a system; absorbing heat in the evaporator coil and then releasing heat in the condenser coil.  R-22 refrigerant is used in 95% of residential air conditioning equipment. R-22 is regulated by international controls under the Montreal Protocol and in the United States, by the Environmental Protection Agency.  R410 A (Puron) is rapidly becoming mainstream for residential systems.  

R410 A Refrigerant - A chlorine-free refrigerant that meets the EPA’s most up to date, stringent environmental guidelines.  

Refrigerant - A chemical that produces a cooling effect, when expanding or vaporizing.  

Refrigerant Lines - Two copper lines that connect the heat pump or outdoor air conditioner to the indoor evaporator coil.

S

Scroll Compressor - A compressor specially designed that operates in a circular motion as opposed to up and down piston action.

SEER - The Seasonal Energy Efficiency Ratio . A rating referring to the energy efficiency of an air conditioner. The higher the SEER, the superior the energy performance, resulting in savings.  

Single Package - A heating and cooling system contained in one outdoor unit.

Split System - A combination air conditioner or heat pump with indoor components.  For example, a blower coil or a furnace.

T

Thermidistat - Monitors humidity and temperature and adjusts cooling or heating system to preferred levels.

Thermostat - A device consisting of a series of sensors and relays that monitor and control the functions of a cooling and heating system, in order to regulate indoor temperature.  

Ton - Unit of measurement for determining cooling capacity.  

Two-Stage Operation - Provides two levels of heat output for greater temperature control.

U

Upflow - A type of furnace that draws cool air from the bottom and blows the warm air out the top in the duct system.  This type of furnace is designed for closet or basement installations.  

V

Variable Speed Motor - Automatically adjusts the control of heat airflow for supreme comfort.

Ventilator - A system that exchanges stale, re-circulated indoor air with fresh, filtered outside air.

Z

Zoning - A method of dividing a home or office into independently controlled comfort areas for enhanced comfort and efficiency.