HVAC Terminology Glossary

HVAC Efficiency and Core Components

AFUE (Annual Fuel Utilization Efficiency): A rating that measures how efficiently a furnace or boiler converts fuel into usable heat over the course of a year.
Air Handler: The indoor unit of an HVAC system that circulates conditioned air through the ductwork. Commonly used with heat pumps.
Air Filter: A component designed to capture dust, pollen, and airborne particles to improve indoor air quality.
BTU (British Thermal Unit): A unit of measurement that represents the amount of heat required to raise one pound of water by one degree Fahrenheit. Used to describe heating and cooling capacity.
BTU Capacity: Indicates how much heat an HVAC system can add or remove per hour.
CFM (Cubic Feet per Minute): Measures the volume of air an HVAC system moves each minute.
Compressor: The primary component of an air conditioner or heat pump that pressurizes refrigerant and enables heat transfer.
Condenser Coil: Located in the outdoor unit, this coil releases heat from the refrigerant into the outside air.
Carbon Monoxide (CO): A colorless, odorless, and dangerous gas produced by incomplete combustion.
Carbon Monoxide Detector: A safety device that alerts occupants when CO levels become hazardous.

Ventilation, Air Quality, and System Types

Damper: A movable valve within ductwork used to control or balance airflow.
Dehumidifier: A system or device that removes excess moisture from indoor air.
Downflow Furnace: A furnace that draws air in from the top and delivers heated air downward.
Dual-Fuel System: A hybrid HVAC system that uses both a heat pump and a gas furnace, switching automatically based on temperature.
Ductless Mini-Split: A heating and cooling system that does not require ductwork and uses individual indoor air handlers.
Ductwork: The network of passages that distribute heated or cooled air throughout a building.
EER2 (Energy Efficiency Ratio 2): Measures cooling efficiency at a specific outdoor temperature under updated testing standards.
Electronic Air Cleaner: A filtration system that uses electrostatic charge to trap airborne particles.
ENERGY STAR®: A government-backed certification indicating energy-efficient appliances and systems.
Evaporator Coil: An indoor coil that absorbs heat from indoor air during the cooling process.

System Operation and Refrigerants

Fan Coil: An indoor unit containing a fan and coil that provides heating or cooling.
Freon® (R-22): A trademarked refrigerant formerly used in HVAC systems, now phased out due to environmental concerns.
Furnace: A heating appliance that produces warm air using gas, oil, or electricity.
Gas Furnace: A furnace that uses natural gas or propane as its fuel source.
Geothermal System: An HVAC system that uses stable underground temperatures for highly efficient heating and cooling.
HSPF2 (Heating Seasonal Performance Factor 2): Measures the seasonal heating efficiency of heat pumps.
HVAC: Heating, Ventilation, and Air Conditioning; systems that regulate indoor temperature, humidity, and air quality.
Heat Exchanger: Transfers heat from combustion gases to air in a furnace.
Heat Pump: A system that provides both heating and cooling by transferring heat between indoor and outdoor environments.
Horizontal Furnace: A furnace designed for installation in tight spaces such as attics or crawl spaces.

Controls, Sizing, and Certifications

Humidifier: Adds moisture to indoor air to maintain comfortable humidity levels.

Humidistat: A control device that monitors and regulates indoor humidity.
Hybrid Heating System: Automatically switches between heating sources to optimize efficiency.
Indoor Air Quality (IAQ): Refers to the cleanliness and health of indoor air.
Load Calculation: A technical assessment used to determine the correct HVAC system size.
Lowboy Furnace: A compact furnace designed for low-clearance installations.
MERV Rating: Measures how effectively an air filter captures airborne particles.
Matched System: HVAC components designed to work together for optimal performance.
Multipoise Furnace: A furnace that can be installed in multiple orientations.
NATE Certification: An industry-recognized credential validating HVAC technician expertise.

Refrigerants and Environmental Innovation

Oil Furnace: A heating system that uses fuel oil to generate heat.
Puron® (R-410A): A refrigerant that replaced R-22 with improved efficiency and reduced environmental impact.
R-22: A refrigerant phased out due to ozone depletion.
R-410A: A widely used refrigerant offering higher efficiency and lower environmental risk.
R-454B: A next-generation refrigerant with significantly lower global warming potential.
Reciprocating Compressor: A piston-based compressor typically found in older systems.
Refrigerant Recovery: The process of capturing and recycling refrigerant for environmental compliance.
Refrigerant Lineset: Copper tubing that carries refrigerant between indoor and outdoor units.

Smart Technology and Seasonal Ratings

Remote Access: The ability to monitor and control HVAC systems via smartphone or internet-enabled devices.
Remote Sensor: A temperature sensor placed away from the thermostat for improved comfort accuracy.
Retention Head Burner: A high-efficiency burner used in oil furnaces.
SEER2: A revised efficiency rating measuring seasonal cooling performance under updated standards.
Scroll Compressor: A quiet, efficient compressor using spiral scroll technology.
Smart Thermostat: A programmable thermostat that adjusts temperature automatically to save energy.
Thermal Learning: A thermostat feature that anticipates heating or cooling needs based on past behavior.

Need Help Understanding Your HVAC System?

Knowing HVAC terminology helps you make confident decisions about comfort, efficiency, and system upgrades. If you have questions or want expert guidance, contact Tidelands A/C & Refrigeration Inc. at (843) 705-4822 or email brett.eason@tidelandsairconditioning.com to speak with an experienced HVAC professional.

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