Glossary of Terms
Air Handler - Indoor half of an electric split system. The air handler has a blower section and evaporator coil all in one unit. Air handlers also include a heat strip, which is available in several different sizes. Generally, air handlers are compatible with either a heat pump condenser or an air conditioner condenser.
Cased Coil - An evaporator coil that is enclosed in a protective case. In general, cased coils are used with a gas furnace and an air conditioner condenser. The condenser and cased coil work together to provide your home with cool air while the gas furnace provides heat.
Condenser - Outdoor half of an electric or gas furnace split system. The condenser has a compressor, condenser coil and fan. You can purchase either a heat pump condenser or an air conditioner condenser and they can be matched with either an air handler or a cased coil with a gas furnace.
Air Conditioner - When an air conditioner system is turned to heating, the compressor will shut off and the heat wll come from the electric heat strips. Alternatively, an air conditioner condenser could be paired with a gas furnace. In this scenario, all of the heat will come from the gas furnace.
Heat Pump - When a heat pump system is turned to heating, the entire system, including the flow of refrigerant, will run in reverse. This will be your main source of heat. Heat pump systems also have electric heat strips which are used for back-up heat.
Gas Furnace - In general, a gas furnace will be matched with an air conditioner condenser and a cased coil. The condenser and cased coil will work together to provide cool air while the gas furnace provides heat.
Split System - Refers to a system, either gas or electric, that has both indoor and ourdoor units. You can purchase an Air Conditioner Split System, Heat Pump Split System, Gas Furnace Split System or a Dual Fuel Split System.
Package Unit - Refers to a system, either gas or electric, that is completely self-contained. The condenser and air handler, or condenser, coil and furnace, are all contained in one outdoor unit. You can purchase an Air Conditioner Package Unit, a Heat Pump Package Unit, a Gas/Electric Package Unit or a Dual Fuel Package Unit.
SEER - The Seasonal Energy Efficiency Ratio (SEER) is the most commonly used measure of the efficiency of consumer central air conditioning systems. The SEER rates how many BTUs an air conditioning unit will remove for each watt of electricity consumed. The higher the unit's SEER rating, the more energy efficient it is.
AFUE - The Annual Fuel Utilization Efficiency (AFUE) is the most widely used measure of a boiler or furnace's heating efficiency. It measures the amount of heat actually delivered to your house compared to the amount of fuel that you must supply to the furnace. Thus, a furnace that has an 80% AFUE rating converts 80% of the fuel that you supply to heat -- the other 20% is lost out of the chimney. Note that the AFUE refers only to the unit's fuel efficiency, not its electricity usage.
Variable Speed - Refers to a system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. Variable speed motors are widely used in ventilation systems for large buildings; variable speed motors on fans save energy by allowing the volume of air moved to match the system demand.