Glossary of Terms 


    Annual Fuel Utilization Efficiency, a rating that reflects the efficiency of a gas furnace in converting fuel to energy. A rating of 90 means that approximately 90% of the fuel is utilized to provide warmth to your home, while the remaining 10% escapes as exhaust.


    British Thermal Unit. In scientific terms, it represents the amount of energy required to raise one pound of water one degree Fahrenheit. One BTU is the equivalent of the heat given off by a single wooden kitchen match. For your home, it represents the measure of heat given off when fuel is burned for heating or the measure of heat extracted from your home for cooling.


    A standard of airflow measurement. Cubic Feet per Minute. A typical system produces 400 CFM per ton of air conditioning.


    The output or producing ability of a piece of cooling or heating equipment. Cooling and heating capacity are normally referred to in BTUs.


    The heart of an air conditioning or heat pump system. It is part of the outdoor unit that pumps refrigerant. The compressor maintains adequate pressure to cause refrigerant to flow in sufficient quantities to meet the cooling requirements of the system.

Condenser Coil or Outdoor Coil

    Located in the outdoor unit, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid.


    Found in duct work, this movable plate opens and closes to control airflow. Dampers are used effectively in zoning to regulate airflow to certain rooms.

Down flow Furnace

    A furnace that pulls in return air from the top and expels warm air at the bottom.

Up flow Furnace

    A furnace that pulls return air in from the bottom and expels warm air from the top.

Horizontal Furnace (Cross space or Attic)

    A furnace that lies on its side, pulling in return air from one side and expelling warm air from the other.


    Pipes or channels that carry air throughout your home.

Evaporator Coil

    The coil that is inside your house in a split system. In the evaporator, refrigerant evaporates and absorbs heat from air passed over the coil.

Heat Exchanger

    A device for the transfer of heat energy from the source to the conveying medium.


    A device that injects water vapor into heated air as the air is expelled from the furnace.


    The amount of moisture in the air. Air conditioners remove moisture for added comfort.


    Heating Seasonal Performance Factor, a rating used in measuring the heating efficiency of a heat pump. The higher the number, the more efficient the unit.


    Heating, ventilation and air conditioning.

Package System

    A piece of air conditioning and heating equipment where all components are located in one cabinet. Used occasionally in residential applications, the package unit is installed either beside or on top of the home.

Package Unit– A heating and cooling system contained in one outdoor unit. A package unit is typically installed either beside, on top of the home, or sometimes in the attic.


    A substance that produces a refrigerating effect while expanding or vaporizing.

Refrigerant Lines

    Set of two copper lines connecting the outdoor unit and the indoor unit.


    Seasonal Energy Efficiency Ratio, a rating that measures the cooling efficiency of a heat pump or air conditioner. The higher the number, the more efficient the unit.

Split System

    Refers to a comfort system configuration consisting of components in two locations. Common examples include an outside unit, such as an air conditioner and an indoor unit, such as a furnace and coil.



Switchover Valve

    A device in a heat pump that reverses the flow of refrigerant as the system is switched from cooling to heating. Also called a reversing valve or four-way valve.


    A temperature control device, typically found on a wall inside the home, that consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system. Programmable thermostats allow you to program different levels of comfort for different times of the day.


    A unit of measurement used for determining cooling capacity. One ton is the equivalent of 12,000 BTUs per hour.


    A method of dividing a home into zones and enabling you to control the amount of comfort provided to each place.  

CFM - Stands for cubic feet per minute. This is the amount of airflow that flows through your system. When using air conditioning the rule of thumb is 400 CFM per ton of air conditioning.

For example a 4 ton system has to have a duct system capable of delivering 1600 CFM of airflow.

Energy Star - Is a program of the U.S. Department of Energy and Environmental Protection Agency. It is designed with the purpose of helping consumers identify energy efficient products. We are proud to be part of the energy star program and offer many products that meet their standards.

Heat Pumps - If you only use electricity to heat your home and have to gas then a heat pump is what you need. Heat pumps provide up to three times more heat than the energy they consume! They also double up as an air conditioner too. A heat pump is capable of reducing the amount of electricity you use to heat your home by up to 40%.

Single Stage / Single Speed - This means that the unit is designed to perform at its highest heat mode. Furnaces are always designed to be able to heat your home on the coldest day. The problem with this is that you only need this heating capability a few days of the year. Single speed furnaces do not have the capability to adjust to milder conditions, this causing high temperature swings, a less comfortable living environment and increased energy usage.

Temperature Zoning - Your browser may not support display of this image.Zoning systems allow you to control your heating and cooling comfort where and when you want it. When using zoning you no longer have the problem of over heating and cooling rooms you are not occupying, in order to be comfortable in another. Each zone is equipped with its' own thermostat and air volume damper that opens and closes as needed, based on that zones' thermostat setting. This allows for maximum efficiency with your heating and cooling system. You do not have to buy a new heating or cooling unit to do this; you simply add air volume dampers and controls to your existing duct work. Think of it like controlling the lights inside your house; you only use it where you need it. 

Two-Speed / Two-Stage - The unit is capable of performing at two heating stages. This greatly improves on indoor air circulation, overall comfort and also reduces operating noise. It operates on the lower speed over 90% of the time, which saves the consumer money on fuel and electricity. It only performs at high heat mode when there is a big demand for heat. This creates an overall more comfortable home with less temperature swings that are often associated with single speed furnaces. 

UV Treatment - Your browser may not support display of this image.U.V. air treatment systems can kill up to 87% of known airborne bacteria that passes through your heating and cooling system. This greatly reduces the amount of harmful agents such as mold, pollen, and dust that your family breathes. The lamps are similar to those used in hospitals and laboratories zapping the airborne particles that pass through the light and prevent them from being re-circulated back into the air. The U.V. bulbs are easily added to your existing heating and cooling system and are easy to replace when needed. The treatment comes with a five year warranty and meets the American Lung Association guideline. 

Variable-Speed - Variable speed furnaces offer the quietest most efficient technology on the market today. The blower motor uses only 1/8 of the power of a standard furnace and has the ability to ramp airflow up and down based on temperature demand resulting in maximized home comfort. This furnace is especially effective for those who suffer from high-energy bills or for those with air filtration needs; such as allergy sufferers, pet owners, and those with dust problems. Using this furnace also increases air conditioning efficiency 10%.