HVAC Glossary

Common HVAC terms in one place.
Look up definitions to make learning fast and easy.

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Filter by Topic: All Topics AC Refrigerant Energy Efficiency HVAC Accessory HVAC Certification HVAC Component HVAC Sizing HVAC System Indoor Air Quality Measurements Thermostat Thermostat Wiring

A

AC recharge refers to the process of adding or replacing the refrigerant in an air conditoner or a heat pump...

Energy Efficiency

AFUE (Annual Fuel Utilization Efficiency) measures how effectively a furnace or boiler converts fuel (natural gas or propane) into usable...

Air Conditioner

An air conditioner is an HVAC system that helps regulate temperature and humidity in your home. The unit works by...

An air handler is a part of an HVAC system that circulates conditioned air throughout your home. It works in...

Indoor Air Quality

An air purifier is a device designed to clean indoor air by removing airborne particles, allergens, gases, and microorganisms. Indoor...

HVAC Certification

ASHRAE Certification

ASHRAE certification is a professional credential provided by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. It serves as...

B

A boiler is a heating system that generates heat by boiling water and distributing it throughout a building to provide...

C

Energy Efficiency

Carbon Footprint

A carbon footprint is the total amount of greenhouse gases emitted into the atmosphere by the activities of an individual,...

Cold Climate Heat Pump

A cold-climate heat pump is designed to heat homes even in extreme weather, with some systems performing reliably down to...

Thermostat Wiring

Common Wire Adapter

A Common Wire Adapter, often called a C-wire adapter (CWA), is a device that provides a dedicated C-wire (common wire)...

D

Indoor Air Quality

A dehumidifier is a device that removes excess moisture from the air, helping to maintain ideal humidity levels. Reducing excess...

Dual-Transformer System

A dual-transformer HVAC system uses two independent transformers: one dedicated to heating and the other to cooling. This setup is...

E

Energy Efficiency

Energy Efficiency Ratio (EER)

The Energy Efficiency Ratio (EER) is a key metric used by the US Department of Energy (DOE) to measure the...

Energy Efficiency

ENERGY STAR ® is a certification program developed by the US Environmental Protection Agency (EPA) to identify and promote energy-efficient...

Energy Efficiency

Energy Tax Credit

Energy tax credits are government-backed incentives for homeowners and businesses to invest in energy-efficient technologies and systems. These credits encourage...

F

Energy Efficiency

Fan Energy Rating

The Fan Energy Rating (FER) is a standard set by the US Department of Energy (DOE) that measures the airflow...

A furnace is an HVAC system that generates heat and distributes it throughout indoor spaces using ducts and vents. A...

G

Geofencing Thermostat

A geofencing thermostat is a smart thermostat that creates a virtual boundary or “geofence” around your home and automatically adjusts...

Energy Efficiency

Global Warming Potential

Global Warming Potential (GWP) measures how much heat a greenhouse gas traps in the Earth’s atmosphere over a set period....

H

Indoor Air Quality

A humidifier is a device that adds moisture to indoor air, helping maintain an optimal humidity level for comfort and...

Indoor Air Quality

A humidistat is a device that measures the humidity levels in a space. Also known as a hygrostat, it is...

Indoor Air Quality

A hygrometer is a device used to measure humidity levels in your home. Humidity refers to the amount of water...

I

Indoor Air Quality

Indoor Air Quality (IAQ)

Indoor air quality (IAQ) refers to the levels of pollutants in indoor spaces and how they affect the health and...

Inverter Heat Pump

An inverter heat pump uses a variable-speed compressor rather than a single-speed one. This allows the system to operate at...

J

Thermostat Wiring

In HVAC systems, jumper wires are those handy little electrical wires that connect two terminals on a thermostat or HVAC...

L

Load Calculation

HVAC load calculation is the process of determining the heating and cooling requirements of your home in order to find...

N

HVAC Certification

NATE Certification

NATE Certification is a credential awarded by North American Technician Excellence, a non‑profit organization, to HVACR professionals. NATE ensures HVAC...

O

O/B Reversing Valve

The O/B reversing valve in a heat pump controls the changeover between heating and cooling modes It works by reversing...

P

Indoor Air Quality

Pleated Filters

Pleated filters are air filters installed in HVAC systems, air purifiers, and other IAQ devices. They use a folded sheet...

R

R-410A Refrigerant

R-410A refrigerant was widely used in air conditioners and heat pumps from around 2010 to 2023. It is a hydrofluorocarbon...

R-454B Refrigerant

What Is A Refrigerant? A refrigerant is a chemical used in air conditioning and refrigeration systems. It is found inside...

Thermostat recovery mode starts heating or cooling earlier than your scheduled time. Instead of waiting for the set time to...

S

Sensible heat is the heat energy that causes a change in temperature of a substance but doesn’t modify its state....

T

Two Stage Cooling

A two-stage cooling system relies on a compressor that can operate at two different capacities. Instead of running at 100%...

Two Stage Heating

Two-stage heating refers to an HVAC system that can operate at two distinct output stages or capacities to meet the...

U

Indoor Air Quality

Ultraviolet lights are used to kill microorganisms such as viruses, bacteria, and fungi. In HVAC systems, UV lights are installed...

V

Variable Speed Motor

A variable-speed motor is an advanced technology utilized by modern HVAC systems. It allows your unit to run at different...

Indoor Air Quality

A ventilator plays a crucial role in today’s HVAC systems, enhancing indoor air quality by managing the flow of fresh...

W

Wet Switch Flood Detector

A Wet Switch Flood Detector in HVAC systems is a crucial safety device that detects water and prevents damage from...

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