HVAC GLOSSARY
AFUE
Annual Fuel Utilization Efficiency (AFUE) measures how efficiently a furnace converts fuel into usable heat over a season. A higher AFUE rating means lower energy bills and better fuel efficiency.
AIRFLOW
Movement of air through HVAC systems or ducts. Proper airflow ensures comfort and system efficiency.
AIR-CONDITIONING AND REFRIGERATION INSTITUTE (ARI)
Industry organization that develops HVAC equipment performance standards and certifications.
AIR HANDLER/ COIL BLOWER
Indoor unit that circulates conditioned air through the home. Often includes the evaporator coil.
ATU
Air Terminal Unit; controls airflow to different zones within a building for temperature management.
BIOAEROSOLS
Airborne biological particles like mold, bacteria, or pollen that can affect indoor air quality.
BTU
British Thermal Unit; a standard measure of heat energy used in heating and cooling systems.
British Thermal Units per hour; measures heating or cooling output of HVAC systems.
BTUH
Combined Annual Efficiency, which measures the energy efficiency of a heating system based on the total heat it provides over a year.
CAE
Colorless and odorless gas produced by the incomplete combustion of fuel, posing a health risk if not properly vented in HVAC systems.
CARBON MONOXIDE
CENTRAL AIR CONDITIONING SYSTEM
A system that cools an entire building using a network of ducts to distribute conditioned air.
CFM
Cubic Feet per Minute; this is the unit used to measure airflow within an HVAC system.
COMPRESSOR
Component that pumps refrigerant through an HVAC system under pressure to enable cooling or heating.
CONDENSER COIL
Outdoor coil where refrigerant releases heat absorbed from inside the home.
DAMPER
Adjustable plate inside ducts that regulates or redirects airflow in zoned HVAC systems.
DB
Decibel; unit used to measure the sound level of HVAC equipment.
DOE
Department of Energy; sets standards for HVAC energy efficiency and performance.
DUAL FUEL
A system combining a heat pump and a gas furnace for optimal year-round energy use.
DUCTWORK
Network of air ducts that distribute conditioned air throughout a building or home.
ELECTRONIC AIR CLEANER
Device that removes airborne particles using an electric charge to improve indoor air quality.
ENERGY STAR®
EPA-backed label for HVAC products that meet energy efficiency guidelines.
EPA
Environmental Protection Agency; regulates refrigerants and air quality standards in HVAC.
EVAPORATOR COIL
Indoor coil that absorbs heat from indoor air as refrigerant evaporates inside it.
FAQ
Frequently Asked Questions; offers simple explanations for common HVAC concerns.
GARAGE HEATERS
Heating units designed for garages, workshops, or utility spaces.
HEAT EXCHANGER
Transfers heat from furnace combustion gases to indoor air without mixing them.
HEAT PUMP
An energy-efficient system that can heat and cool a building by transferring heat between the interior and exterior environments.
HORIZONTAL AIRFLOW
HVAC system setup where air is distributed horizontally through ductwork.
HSPF
Heating Seasonal Performance Factor; an efficiency rating for heat pumps that measures their heating output compared to the energy consumed.
HUMIDIFIER
An appliance that adds moisture to the air, helping to prevent dryness and improve comfort in cold weather.
HUMIDISTAT
A device that controls the humidity level in an HVAC system by activating the humidifier or dehumidifier as needed.
HVAC
Heating, Ventilation, and Air Conditioning—systems that provide temperature and air quality control for indoor environments.
INDOOR COIL
The coil inside an air handler or furnace that either absorbs heat or releases cool air into the building’s environment.
ISO 9000
International standards for quality management systems, often applied to the HVAC industry to ensure high production standards.
INTERCONNECTION AGREEMENT
A formal agreement between a homeowner and utility company that sets guidelines for connecting a residential HVAC system to the grid.
MERV RATING
Minimum Efficiency Reporting Value; a scale that rates the effectiveness of air filters in capturing airborne particles.
MICRON
A unit of measurement used to indicate the size of airborne particles that filters can capture; one micron is one millionth of a meter.
NET METERING
A billing mechanism that allows homeowners with solar panels or other energy sources to receive credit for excess energy sent to the grid.
Airborne pollutants that HVAC systems can help filter or exhaust to maintain indoor air quality.
ODORS/CHEMICALS
OUTDOOR COIL
The coil located outside in an air conditioning or heat pump system that absorbs or releases heat to the external environment.
Contaminants such as dust, pollen, and pet dander that can be removed by filters or air purifiers in HVAC systems.
PARTICLES
A thermostat that allows users to set temperature schedules for greater energy efficiency and comfort.
PROGRAMMABLE THERMOSTAT
R410A-REFRIGERANT
An environmentally friendly refrigerant commonly used in modern air conditioning and heat pump systems to replace R-22.
REFRIGERANT
A chemical used in HVAC systems to transfer heat between the indoor and outdoor units, often changing states from liquid to gas and back.
REFRIGERANT LINES
The pipes that carry refrigerant between the outdoor and indoor components of an HVAC system.
SCROLL COMPRESSOR
A type of compressor used in HVAC systems that is known for its energy efficiency and quieter operation.
SEER
Seasonal Energy Efficiency Ratio; a rating used to measure the efficiency of air conditioners in cooling over the course of a season.
SINGLE PACKAGE
An HVAC system where all components are housed in a single outdoor unit.
SPLIT SYSTEM
An HVAC system with separate indoor and outdoor units that work together to heat or cool a building.
THERMIDISTAT
A device that controls both temperature and humidity in an HVAC system.
THERMOSTAT
A device that allows users to control and set the temperature within their HVAC system.
TON
A unit of measurement for cooling capacity; one ton is equal to 12,000 Btu per hour.
TWO-STAGE OPERATION
A system that operates at either a low or high capacity depending on the heating or cooling demand.
UPFLOW
A type of HVAC system configuration where air is pushed upward into the ducts from the furnace or air handler.
VARIABLE-SPEED MOTOR
A motor that adjusts its speed based on demand, improving energy efficiency and comfort in HVAC systems.
VENTILATOR
An HVAC component that helps bring fresh air into a building while exhausting stale air to maintain air quality.
ZONING
The practice of dividing a building into separate areas that can be independently heated or cooled, offering better control over energy use.