HVAC Terminology

To familiarize yourself with equipment used in typical HVAC projects, here are a few definitions of common terms.

Common HVAC Terms and Definitions

The list below contains terminology you may hear or read when speaking with an HVAC dealer or when researching home comfort products.

System Equipment

Air Handler
The portion of the central air conditioning or heat pump system that moves heated or cooled air throughout a home's ductwork. In some systems, a furnace handles this function.
Condensing/Outdoor Unit
The portion of a central air conditioning system that is located outside the home and functions as a heat transfer point for collecting heat from and dispelling heat to the outside air.
Heat Pump
An air conditioner that contains a valve that allows it to alternate between heating and cooling.
Single Package
A year-round heating and air conditioning system that has all of the components completely encased in one unit outside the home.
Split System
A heat pump or central air conditioning system with components located both inside and outside the home. The most common design for home use.

Unit Components

The pump that moves the refrigerant from the indoor evaporator coil to the outdoor condensing unit and back to the evaporator. The compressor functions as the heart of the system, because it circulates the refrigerant in a loop.
Condenser Coil
A network of refrigerant-filled tubes where heat leaves the hot refrigerant vapor. The vapor then condenses into a liquid capable of absorbing more heat.
Evaporator Coil
The portion of a heat pump or central air conditioning system that is located in the home and functions as the heat transfer point for warming or cooling indoor air.

Efficiency Ratings/Measurement

Annual Fuel Utilization Efficiency. A measure of a furnace's heating efficiency. The higher the AFUE%, the more efficient the product. The government's established minimum AFUE rating for non-weatherized gas furnaces vented through a chimney is now 81%.
British Thermal Unit. The amount of heat required to raise the temperature of one pound of water (about one pint) by one-degree F.
Heating Seasonal Performance Factor. A measure of a heat pump's heating efficiency. The higher the HSPF, the more efficient the product. There is no government established minimum HSPF rating for heat pumps.
Minimum Efficiency Reporting Value. A measure of air filter efficiency. The higher the rating, the more efficient a filter is at capturing the smallest particles in the air.
Seasonal Energy Efficiency Ratio. A measure of an air conditioner's cooling efficiency. The higher the SEER, the more efficient the product.

Other HVAC Terms

Balance Point
An outdoor temperature, usually between 30° F and 45° F, at which a heat pump's output equals exactly the heating needs of the home. Below the balance point, supplementary electric resistance heat is needed to maintain indoor comfort.
Heat Source
A body of air or liquid from which heat is collected. With YORK® heat pumps, the air outside the home is used as the heat source during the heating cycle.
Load Calculation
Performed by an HVAC professional, this calculation helps determine what size system is needed for a home (how much heating or cooling) based on how much heat is gained or lost.
Supplementary Heat
Auxiliary or emergency heat, usually electrical resistance heat, provided at temperatures below a heat pump's balance point.

Download the Quick Study Guide

You don’t have to know all the ins and outs of an HVAC system to make an intelligent buying choice. But there are a few things you should know to ensure you get the right system for your needs. We’ve put together a brief overview to help answer a few common questions and provide some money-saving advice.

Call (877) 874-7378
Contact Us
Contact your local YORK dealer