HVAC Glossary
The HVAC Terms Every Homeowner Should Know
HVAC stands for heating, ventilation and air conditioning, but beyond that, there's still a lot of HVAC terminology you should know. In order to be an informed homeowner about your own residential HVAC system, we've made it easy to find out what those acronyms and industry-specific jargon mean.
Residential HVAC System Equipment
Air Handler
The portion of a 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 located outside the home. It 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 which allows for alternation between heating and cooling.
Single Package
A year-round heating and air conditioning system with all components 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
Compressor
The pump that moves 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 as it circulates refrigerant in a loop.
Condenser Coil
A network of refrigerant-filled tubes where heat leaves hot refrigerant vapor. This vapor then condenses into a liquid capable of absorbing more heat.
Evaporator Coil
The portion of the heat pump or central air conditioning system located in the home. It functions as the heat transfer point for warming or cooling air.
Efficiency Ratings/Measurement
AFUE %
It stands for annual fuel utilization efficiency, a measure of a furnace's heating efficiency. The higher the AFUE, the more efficient the product. Currently, the government's established minimum AFUE rating for non-weatherized gas furnaces vented through a chimney is 81% AFUE.
BTU
It stands for British thermal unit, the amount of heat required to raise the temperature of one pound of water (or about one pint) by one degree Fahrenheit.
HSPF2
It stands for heating seasonal performance factor, a measure of a heat pump's heating efficiency. The higher the HSPF2, the more efficient the product. Unlike furnaces with AFUE, there isn't a government established minimum HSPF2 rating for heat pumps.
MERV
It stands for minimum efficiency reporting value, a measure of air filter efficiency. A higher MERV rating means a filter is more efficient in capturing particles in the air.
SEER2*
It stands for seasonal energy efficiency ratio, a measure of an air conditioner's cooling efficiency. A SEER2 rating may be as low as 13, 14, 15, or 16 with higher performing models obtaining SEER2 levels of 17, 18, 19, 20 or higher. For example, a product with a 21 SEER2 rating would be an extremely efficient product.
Ton
A ton is the cooling capacity of an air conditioning system. It's equal to the amount of heat required to melt one ton of ice over 24 hours. For instance, a one-ton air conditioner would be rated at 12,000 BTU per hour (BTUh).
*As of January 1, 2023, The U.S. Department of Energy upgraded its minimum standards and testing from SEER to SEER2.
Other Common HVAC Terms
ASHRAE
The American Society of Heating, Refrigerating and Air-Conditioning Engineers is a not-for-profit trade organization founded in 1894. Its stated goals include the advancement of heating, ventilation, air conditioning and refrigeration system design and construction.
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 this point, supplementary electric resistance heat is needed to maintain indoor comfort.
Heat Source
A body of air or liquid from which heat is collected. For example, YORK® Heat Pumps use air from outside the home as the heat source during the heating cycle.
Load Calculation
Completed by an HVAC professional, load calculation helps determine the system size necessary for a home (heating or cooling), based on how much heat is gained or lost.
Supplementary Heat
Auxiliary or emergency heat, usually electrical resistance heat, provided when temperatures are below a heat pump's balance point.
Variable Speed
Refers to a motor that operates at different speeds to more accurately control the flow of heated or cooled air around the home.
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Getting Started
If you're looking for HVAC experts or a reliable HVAC company, nothing compares to YORK®. Established in 1874 in York, Pennsylvania, YORK® has a legacy of being a trusted leader for all things residential HVAC. If you're considering YORK® HVAC equipment for your home's heating and cooling needs, here's what to think about first.
The Purchase Process
Whether you're repairing a current HVAC system or upgrading your residential HVAC equipment, there's a lot to consider.
Working With an HVAC Dealer
From choosing an HVAC dealer to preparing for your first visit, here's everything you need to know before making a call.