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What’s the difference between AC and ACH? Know what the V stands for in HVAC?

When it comes to heating, ventilation, and air conditioning (HVAC), familiarizing yourself with commonly used terms and acronyms will not only help you, but it will also help a professional technician aid you in purchasing a system or addressing a problem.

Get to know your HVAC unit better with the alphabetized glossary of terms the team at Hoffner Heating and Air Conditioning is providing below. With our help, you’ll be more confident in knowing some of the ins and outs of your system.

— A

What is ACCA?

ACCA is the abbreviation for the Air Conditioning Contractors of America. The ACCA offers an online store, contractors, and other information regarding HVAC units and HVAC-related events.

What is ACH?

ACH is the abbreviation for air changes per hour. An increase in ACH indicates better quality ventilation.

What is AFUE?

AFUE is the abbreviation for Annual Fuel Efficiency Ratio. AFUE measures the heating efficiency of your furnace.

What is AGA?

AGA is the abbreviation for the American Gas Association, Inc.

What is the AHRI?

AHRI is the abbreviation for the Air-Conditioning, Heating, and Refrigeration Institute. This organization monitors the environmental changes caused by HVAC units and seeks to improve both safety and efficiency.

What is an Air Conditioner?

An air conditioner is a unit that removes heat and moisture from a space by drawing it outside, resulting in cooler air.

What is an Air Filter?

An air filter is a device that catches small particles and removes them from the air. When it comes to air filters, there is not a one-size-fits-all policy. Air filters differ by unit, size, and a wide range of appliances.

What is an Alternating Current (AC)?

An alternating current is an electric current that reverses direction.

What is ASHRAE?

ASHRAE is the abbreviation for the American Society of Heating, Refrigerating and Air-Conditioning Engineers. The ASHRAE advocates for sustainability within the HVAC industry.

— B

What is a Bioaerosol?

Bioaerosol is short for biological aerosols, which are airborne particles that come from living organisms. Biological aerosols are typically fungal or moldy in nature. These particles appear in warm, moist places and have the potential to be dangerous.

What is a BTU?

BTU is the abbreviation for British Thermal Units. British Thermal Units are a measure of heat energy. One BTU is the amount of heat needed to raise a pound of water one degree Fahrenheit.

White Pressure Gauges

— C

What is CAE?

CAE is the abbreviation for Combined Annual Efficiency. CAE measures the amount of heat produced per dollar of fuel heating your home.

What is CFM?

CFM is the abbreviation for cubic feet per minute, a measurement of airflow volume.

What is a Chiller?

A chiller is a unit attached to an evaporator that removes heat from liquids.

What is a Coil?

A coil is the integral part of a heating unit which absorbs heat from the air.

What is a Compressor?

A compressor is a pump that pushes refrigerant through your cooling unit. It is located indoors.

What is a Condenser Coil?

A condenser coil is a piece of equipment that removes heat from the refrigerant. It is primarily located outdoors.

What is a Controller?

The controller is a piece of equipment that operates the HVAC unit by directly operating its heating and cooling properties. It functions similarly to a thermostat, and is often located on a wall.

— D

What is a Damper?

Using metal plates, a damper regulates, restricts, and also redirects airflow.

What is a Dehumidifier?

A dehumidifier is a unit that removes moisture from the air.

What is DOE?

DOE is the abbreviation for the U.S. Department of Energy.

What is a Downflow Furnace?

A downflow furnace is a unit that takes in cold air at the top and dispels warm air through the bottom.

What is Dry Bulb Temperature?

Dry Bulb Temperature is a measure of temperature without considering humidity.

What is Ductwork?

Ductwork refers to the ducts that guide air throughout the home.

— E

What is EER?

EER is the abbreviation for Energy Efficiency Ratio, the ratio of cooling (British Thermal Units) to electrical energy (watts). An air conditioner is more efficient with a higher EER.

What is the EPA?

EPA is the abbreviation for the United States Environmental Protection Agency. The EPA site supplies information regarding laws and regulations for the environment as well as other environmental topics.

What is an Evaporator Coil?

An evaporator coil is an indoor coil that contains refrigerant and absorbs heat from your home.

What is an Expansion Valve?

An expansion valve measures levels of refrigerant.

— F

What is a Flue?

A flue is a duct that directs and removes smoke.

— G

What is GAMA?

GAMA is the abbreviation for the Gas Appliance Manufacturers Association. It is an association of manufacturers of gas, oil, electric appliances, equipment, and other related products.

What is a Grille?

A grille is a cover for an air duct.

Two N95 white masks and one blue masks

— H

What is HSPF?

HSPF is the abbreviation for Heating Seasonal Performance Factor. The HSPF measures the efficiency of heat pumps. A higher rating indicates more efficiency.

What is a Humidistat?

A humidistat controls the amount of moisture in the air.

What is HVAC?

HVAC is the abbreviation for Heating, Ventilation, and Air Conditioning.

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— I

— J

— K

What is a Kilowatt?

A Kilowatt (kW) is a unit of power equal to 1,000 watts.

— L

What is Latent Heat?

Latent Heat is the amount of heat remaining after a change of moisture in the air.

What is Load?

Load indicates the amount of heating or cooling necessary to control the temperature in your home.

— M

What is a MERV Rating?

Minimum Efficiency Reporting Value Rating, MERV Ratings range from 1-16, indicating the efficiency of an air filter. Higher ratings ensure that less particulate matter passes through a filter.

— N

What is NATE?

NATE is an abbreviation for North American Technician Excellence. It is a non-profit certification organization for heating, ventilation, air conditioning, and refrigeration technicians.

What is NEC?

NEC is an abbreviation for the National Energy Council and National Electric Code.

What is Net Metering?

Net Metering is a system that allows homeowners who generate their own solar electricity to redirect and store energy back into the grid.

— O

What is OAT?

OAT is the abbreviation for Outside Air Temperature.

White and blue thermostat set to 63 degrees

— P

What is a Pilot Light?

A pilot light is a continuous gas flame that allows for the lighting of a burner.

What is Plenum Space?

Plenum Space is a designated area that controls airflows for heating and cooling purposes.

What is PSI?

Pound per Square Inch, PSI is a unit of pressure measurement.

What is PSIA?

Pounds per square inch absolute, PSIA is a measure of absolute pressure relative to vacuum.

What is PSIG?

PSIG is the abbreviation for pounds per square inch gauge.

— Q

— R

What is a Radiant Floor?

A radiant floor heats a room through the floor through water-heated tubing or electric coils.

What is Refrigerant?

Refrigerant is a liquid-based chemical that induces a cooling effect.

— S

What is a Scroll Compressor?

A scroll compressor is a device that works in a circular motion for compressing air or refrigerant.

What is SEER?

SEER is the abbreviation for Seasonal Energy Efficiency Ratio. SEER measures the efficiency of the HVAC system with a minimum rating of 13 and a maximum of 24 with 24 being the most productive.

What is Sensible Heat?

Sensible heat is the amount of energy needed to change the temperature without a phase change. A phase change is when matter changes from one state to another—for example, a liquid to a solid or a liquid to gas.

What is Subcooling?

Subcooling is the act of lowering the temperature of the refrigerant.

— T

What is a Thermidistat?

A thermidistat is a device that maintains both temperature and humidity in the home.

— U

What is an Upflow Furnace?

An upflow furnace, taking in cold air from the bottom and dispersing heat through the top, moves air upward from the lowest level of your home.

— V

What is VAV?

VAV is the abbreviation for Variable Air Volume, which is a type of HVAC system with fluctuating airflow.

— W

What is a Wet-Bulb Thermometer?

A wet-bulb thermometer is a thermometer covered in a water-soaked cloth indicating the lowest temperature air can be cooled by evaporation.

— X

— Y

— Z

What is Zoning?

Zoning is an HVAC system that uses dampers to control the temperature in specific areas of the home.

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Want to Learn More About Your HVAC System?

We know: It’s a lot to consider and take in. Rest assured that Hoffner Heating and Air Conditioning is here to help you with all of your heating and cooling inquiries, from the basics to the most advanced questions. No prior knowledge required—we’re here to help you become an expert on your HVAC unit. To learn more and connect with our team, visit our contact page, blog, or call us at 412-376-9080.