Here is a glossary of common heating and air conditioning terms and their definitions. Knowing these terms will help you better understand your heating and cooling system.
Glossary of HVAC Terms
Air Cleaner: This is the part of your indoor air quality system that filters the air, removing harmful contaminants and allergens.
Air Conditioning, Heating and Refrigeration Institute (AHRI): AHRI is an association that maintains industry standards and lobbies for reform in the government.
Air Conditioner: An air conditioner comes in either split or package systems. It is the most common way to cool your home.
Air Handler: An air handler is the part of your split system air conditioner that works with your condenser outside to force air through your ductwork.
Airflow: This is a measurement of the amount of air a device is able to force into your home. It is measure in CFM and the measurement determines how effective your system is working and if there will be hot or cold spots.
AFUE: AFUE is a measure of heating unit efficiency in furnaces. It tells you how efficient your heating unit is and how much heating power it has.
BTU: BTUs are a measure of the amount of heat it takes to raise one pound of water one degree Fahrenheit. In HVAC, this typically measures the heating capacity of a furnace or air conditioner – the higher the BTU rating, the larger the heating capacity of your HVAC unit.
Capacity: Capacity refers to how much space your heating or cooling system can effective heat or cool. Normally heating capacity is expressed in BTUs and cooling capacity is expressed in tons.
Carbon Monoxide: An odorless, colorless gas that is harmful and deadly. carbon monoxide detectors let you know if your house has levels of carbon monoxide present.
Certified Matched System: The Air Conditioning, Heating and Refrigeration Institute (AHRI) uses this system to test and certify your heating and cooling equipment can perform properly under certain conditions. Without this certification, you may not get the performance you expected.
Compressor: The compressor is the heart of your air conditioner or heat pump. This component is responsible for pumping refrigerant through your system. It also pressurizes the refrigerant and gets it ready for heat transfer in the condensing coil.
Condenser Coil: The condenser coil is part of the outdoor portion of your central cooling system. This system passes refrigerant through it and facilities heat transfer. It will either release or collect heat from the outside air.
Condensing Unit: Every split system cooling system contains two parts: the indoor furnace/air handler and the outdoor condensing unit. The condensing unit typically contains the compressor and condenser coil (among other things).
CFM: CFM is a measure of airflow in HVAC equipment.
Damper: A Damper is a movable plate used to direct air flow in your ductwork.
Downflow: A Downflow is a type of furnace usually seen in attics. It takes cool air from the top and blows warm air down. Dry-Charged Unit: A dry-charged unit is a heat pump or air conditioner that is shipped from the factory without refrigerant.
Dual-Fuel: A dual-fuel system is any unit that is powered by gas and electricity.
Ductwork: Ductwork in your home is the hollow metal box like pipes that bring air to your rooms or return air to your HVAC system.
Electronic Air Cleaner: Electronic air cleaners are air cleaners that work with electricity.
EER: EER is a measurement of cooling efficiency. It is determined by BTU/watts used. EER is not typically used to label the efficiency of new cooling equipment.
ENERGY STAR: High-efficiency heating and air conditioning equipment is rated according to ENERGY STAR efficiency standards.
Evaporator Coil: Located in either your air handler or on top of your furnace, the evaporator coil converts liquid refrigerant into gas. Heat from air blown over the coil is transferred to the refrigerant and the cooled air is then distributed throughout your house.
Fixed Speed: Fixed-speed motors maintain consistent airflow. They are the HVAC industry standard.
Formicary Corrosion: This type of corrosion is the leading cause of coil leaks especially where moisture is a problem. Organic acids, water, oxygen and copper mix together to form this type of corrosion.
Furnace: A furnace is a heating unit that uses either natural gas or oil to heat your home.
Gas Pack: A packaged HVAC unit that contains all of the components of a furnace and an air conditioner.
Heat Exchanger: The main part of the furnace that transfers heat into the air in your furnace, before it is distributed throughout your home.
Heat Pump: An HVAC unit that handles both heating and cooling.
HEPA Filter: HEPA stands for ‘High-Efficiency Particulate Absorption’ and is a standard for the most effective air filters. HEPA filters are high-efficiency filters that block the tiniest particles and allergens from entering your home.
Horizontal Flow: A type of furnace, which draws air from one side, heats the air and then sends it out the other side.
Humidifier: Humidifiers add moisture to air as it exits the furnace to bring up the relative humidity.
Humidity: Humidity is an indication of the amount of moisture in a given volume of air. In HVAC, humidity levels are measured in terms of relative humidity (the amount of moisture in the air expressed as a percentage of how much water can be in a volume of air at a particular temperature).
HVAC: HVAC stands for ‘Heating Ventilation and Air Conditioning.’ This term refers to any equipment, contractor, company, etc., that has to do with heating and cooling .
IAQ: IAQ stands for ‘Indoor Air Quality’ and is the combination of air cleaners, humidifiers, filters, etc. that help improve the quality of your indoor air.
Inverter:An inverter in an air conditioner is used to control the speed of the compressor motor to drive variable refrigerant flow in an air conditioning system to regulate the conditioned-space temperature.
IQ Drive: This is a line of products that is at the peak of efficiency and quality. iQ Drive products employ temperature modulation for energy-efficient performance and include air conditioner, heat pumps, air handlers and furnaces. These units also include additional home comfort and noise reduction features for premium, quiet performance.
Lineset: The lineset is the part of your cooling system that circulates the refrigerant through the various components.
Load Calculation: Load calculations are performed to find the correct size air conditioner, heat pump, furnace, etc. for your home.
Media Filter: A media filter traps all the harmful particles in your indoor air. It is located in the air cleaner. It’s effectiveness is measured in microns.
Micro-Channel: Micro-Channel is a design used in coils to combat corrosion and reduce the overall weight of the unit. All-aluminum Micro-Channel coils are the most resistant against formicary corrosion. In addition, they require less refrigerant and transfer heat better.
Micron: Microns are the unit of measure used to define the efficiency of a filter. The smaller the micron size, the more particles your air filter will be able to block.
NATE: A technician certification network that designates the best HVAC contractors. If you are looking for contractor excellence, go with a NATE certified technician.
Packaged System: Packaged systems are one of the two types of system setups. A packaged unit combines all the necessary system components in one convenient unit. There are several types of packaged units, including: air conditioners, heat pumps, gas packs and dual-fuel systems.
R-22: R-22 is a type of refrigerant known as Freon that has been used over the years in cooling equipment. It is being replace with R-410A because it was found to be harmful to the ozone.
R-410A: R-410 is an environmentally-friendly, non-ozone-depleting refrigerant that is replacing R-22 in heat pumps and air conditioners.
Refrigerant: The refrigerant is a chemical flows through a central cooling system. Refrigerant removes heat from the air as it evaporates and adds heat to the air when it condenses.
Rotary Compressor: A rotary compressor works like any other compressor – its job is to compress refrigerant, raising the temperature and pressure.
Scroll Compressor: The scroll compressor is a type of compressor that is typically considered more efficient and quieter than the rotary compressor.
SEER: SEER is a measure of an air conditioner or heat pump’s cooling efficiency over a given cooling season (this is figured out by estimating how many hours your cooling system will be in operation during the season). If the unit has a higher SEER rating, it means it is more efficient.
Single-Stage: Basic heating and air conditioning units operate in one stage.
Split System: A split system is one of the two types of system setups. A split system contains both an outdoor and an indoor component. Outdoor components include the air conditioner or heat pump condensing unit and the indoor components can include one, or more, of the following: evaporator coil, air handler or furnace.
Thermostat: A device that monitors and controls the temperature inside your home.
Ton (of air conditioning): A ton of air conditioning refers to capacity in relation to melting one ton of ice in 24 hours. The capacity is measured in BTUs. 288,000 BTU are required to melt one tone of ice every 24 hours. A 2-ton air conditioner has a 24,000 BTU/h capacity.
Two-Stage: Two-Stage HVAC systems are as efficient as single-stage – the difference is in comfort level. These units have two capacities: a higher and a lower capacity. Two-stage systems are able to operate longer at the lower capacity that mixes the air better and is quieter to run.
Upflow: A type of furnace usually found in basements. They draw cool air from the bottom and blow the warmed air out the top.
Variable Speed: Variable-speed blower motors are able to provide more even temperatures throughout the home by varying the airflow depending on need.
UV Light Systems: UV light systems use the UV light spectrum to kill and control airborne microbes.
Ventilator: A ventilator captures heating or cooling energy from stale air and transfers it to fresh incoming air.
Zone: Zoning allows you to program or control the heating or cooling delivered to a specific area of your home. This allows for more efficient heating and cooling where it is needed.
We hope you found this glossary of HVAC terms helpful. If you have additional questions, call your ADA heating and air professional, they will be happy to help you.
