AMI Services, Inc. Heating, Air Conditioning, Ventilation The HVAC/R Specialists

Glossary of Terms

AFUE- Annual Fuel Utilization Efficiency. A measure of a gas furnace's efficiency in converting fuel to energy ^_ the higher the rating, the more efficient the unit.

BTU- British Thermal Unit. This is the amount of heat it takes to raise one pound of water one degree Fahrenheit. It represents the measure of heat given off when fuel is burned for heating or the measure of heat extracted for cooling.

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

Capacity- The output or producing ability of a piece of cooling or heating equipment.
Cooling and heating capacities are referred to as BTUs.

Compressor- The heart of an air conditioning or heat pump system. It is part of the outdoor unit and pumps refrigerant in order to meet the cooling requirements of the system.

Condenser Coil or Outdoor Coil- In an air conditioner, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid. In a heat pump system, it absorbs heat from the outdoors.

Damper- Found in ductwork, this movable plate opens and closes to control airflow. Dampers can be used to balance airflow in a duct system. They are also used in zoning to regulate airflow to certain rooms.

Ductwork- Pipes or channels that carry air throughout a facility. Ductwork is critical to
performance ^_ in fact, it's as critical as the equipment.

Evaporator Coil or Indoor Coil- The other half of your air conditioning system located in the indoor unit. This is where the refrigerant evaporates as it absorbs heat from the air that passes over the coil.

Gas Furnace Heat Exchanger - Located in the furnace, the heat exchanger transfers heat to the surrounding air, which is then pumped throughout the facility.

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

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

Refrigerant- A chemical that produces a refrigerating effect while expanding and vaporizing and is regulated by international controls under the Montreal Protocol and in the United States by the Environmental Protection Agency. It is scheduled to be in production until the year 2020. It's used in approximately 95 percent of air conditioning equipment manufactured in the U.S. today.

SEER- Seasonal Energy Efficiency Ratio. A measure of cooling efficiency for air conditioners and heat pumps. The higher the SEER, the more energy efficient the unit. The government's minimum SEER rating is 10. (It's similar to comparing miles per gallon in automobiles.)

SEET- Seasonal Extreme Environmental Test Lab. This is American Standard's torture chamber for heating and air conditioning systems, where five years of service are condensed into 16 torturous weeks. If a product doesn't make it through SEET lab, it's not manufactured. All equipment is tested by the manufacturer before it is used in your facility.

Split System- The combination of an outdoor unit (air conditioner or heat pump) with an indoor unit (furnace or air handler). Split systems must be matched for optimum efficiency.

Thermostat- A thermostat consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system.

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

Zoning- A method of dividing a building into different comfort zones so each zone can be independently controlled depending on use and need.