HVAC Terminology and Definitions

AFUE - An acronym which stands for Annual Fuel Utilization Efficiency wherein the higher the number, the more efficient the unit is rated. The Deartment of Energy's (DOE) minimum efficiency level is 78%.

Air Handler - This is the indoor section of a split system, also known as a fan coil, which serves to move air through your ductwork via a blower motor.

Ambient Temperature - This is the air temperature surrounding the particular piece of equipment.

BTU - Na acronym which stands for British Thermal Unit (Btu). This is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. These ratings are vailable on all hvac units. The heating Btu rating and air conditioner Btu rating typically are not the same for a single system.

Condensing Unit - This is the outdoor section of a split system air conditioning system which cools refrigerant that circulates in the HVAC system. This unit requires periodic cleaning to operate efficiently.

COP - An acronym which stand for Coefficient of Performance. This is a ratio that compares a heat pump's heating efficiency to electric resistance heating. A heat pump's system COP will decrease as outdoor temperatures drop (becoming less effective), and at this point the heating will be provided by electric heat strips.

Energy Star – HVAC products with the ENERGY STAR symbol are deemed to be environmentally friendly by meeting strict energy efficiency guidelines set by the EPA and the DOE.

Evaporator Coil – This element transfers heat to provide cooled, dehumidified air into your home or business. This element needs periodic cleaning to work efficiently.

Heat Pump – Provides heating and cooling comfort as a split system or as a packaged system. A heat pump can be combined with a gas furnace for better performance when temperatures fall below freezing.

HSPF - An acronym which stands for Heating Season Performance Factor and indicates the comparitive level of a heat pumps' heating efficiency. A higher HSPF number indicates greater efficiency.

Important! Before replacing a heating or cooling system you should get a Load Calculation done by a reputable HVAC contractor. Energy efficiency and performance factors of various units can then be considered to design the best system for your home or business. Modern equipment designs may allow for a unit that is smaller than the unit to be repalced.

Packaged System - Packaged units provide both heating and cooling from one unit that is placed outside the home or business. Packaged units are available in several combinations of fuel sources - gas heat/electric cooling; heat pump; electric heat/electric cooling; oil heat/electric cooling.

SEER Rating - A measurement of the efficiency of cooling products which stands for stands for Seasonal Energy Efficiency Rating. Higher SEER ratings indicate higher energy efficiency. SEER rating is generally more important than the size of your air conditioning unit.

Split System - This describes an air conditioning or heat pump system that is split into two sections - an outdoor section and an indoor section. A typical split system is an air conditioning condensing unit on a concrete pad on the outside of a building with a furnace and air handler in a garage, attic or mechanical room.

Thermo Coupler - a heat sensitive device used in a gas furnace which triggers the ignition of burners based.

Thermostat - is a control device located inside your home or office used to set, maintain and control temperature levels. A thermostat will automatically turn on an HVAC system to maintain a preset temperature level and should not be used as a switch. Thermostats must be matched to the type of system used and wired accordingly.

Ton - A measurement of the capacity of an air conditioning system (not weight). One ton of air conditioning equals 12,000 Btu's per hour. This means that a "one ton" air conditioning system has the capability of removing 12,000 Btu's of heat per hour from your home or business.