HVAC Abbreviations List part-1 | Essential Terminology for Modern HVAC Systems

HVAC Abbreviations List part-1 | Essential Terminology for Modern HVAC Systems

Welcome to Insight Control system

Introduction to HVAC Abbreviations and Technical Terms

• Understanding HVAC (Heating, Ventilation, and Air Conditioning) terminology is essential for technicians, engineers, designers, and students working in the building automation or mechanical services industry.
• This comprehensive guide compiles the most commonly used HVAC abbreviations covering air conditioning, ventilation, thermal systems, energy performance, filtration, and indoor air quality.

• These abbreviations help professionals communicate effectively, interpret technical drawings, understand equipment specifications, and follow international engineering standards. This resource is designed to be simple, clear, and highly valuable for beginners and experts alike.

🧾 HVAC Abbreviations (A to Z)

Below is the entire abbreviation list, organized alphabetically for easy navigation.

∘₊✧─────✧₊∘ A ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
ACH	Air changes per hour	✔️ Air Changes Per Hour means how many times the air inside a room is completely replaced with fresh or clean air in one hour.
ADPI	Air diffusion performance index	✔️ Air Diffusion Performance Index is a measure used in HVAC to show how comfortable the airflow feels in a room.
AQI	Air Quality Index	✔️ Air Quality Index is a number that tells you how clean or polluted the air is outside.

∘₊✧─────✧₊∘ B ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
BEER	Beverages	✔️ Beverages means rooms used for storing or processing drink products that need controlled temperature and environment.
BVU	Bi-directional Ventilation Unit	✔️ A Bi-Directional Ventilation Unit is an HVAC device that can both supply fresh air into a room and extract stale air out of the room using the same unit.

∘₊✧─────✧₊∘ C ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
CAV	Constant Air Volume	✔️ A Constant Air Volume system is an HVAC system that supplies the same amount of air all the time, no matter how hot or cold the room becomes.
CERs	Controlled environment rooms	Controlled Environment Rooms are special rooms where temperature, humidity, airflow, and cleanliness are kept at very specific levels all the time. These rooms are used when products, experiments, or processes need a stable and controlled indoor environment.
CFD	Computational fluid dynamics	✔️ Computational Fluid Dynamics is a computer-based method used to study how air moves inside a room, building, duct, or HVAC system.
CW	Chilled water	Chilled Water is cold water used in HVAC systems to cool buildings. It is produced by a chiller and then circulated through pipes to air handling units or fan coil units.
CLTD	Cooling load temperature difference	Cooling Load Temperature Difference is a simplified method used in HVAC design to estimate how much heat enters a building through walls, roofs, and windows. It represents the effective temperature difference between outdoor and indoor conditions after considering factors like sun heat, material type, time of day, and building orientation.
CNR	Composite noise rating	Composite Noise Rating is a method used in HVAC to evaluate the overall noise level produced by equipment such as fans, ducts, and air-handling units. It combines noise from different frequency bands into a single value to show how loud the system will sound to occupants.
COP	Coefficient of performance	The Coefficient of Performance (COP) is a measure of how efficiently an HVAC system (like a chiller or heat pump) uses energy. It is the ratio of useful heating or cooling output to the electrical energy input.
CTIAC	Combustion turbine inlet air cooling	Combustion Turbine Inlet Air Cooling (TIAC) is a method used to cool the air entering a gas turbine. Cooler air is denser, which increases the turbine’s power output and improves efficiency, especially during hot weather.
CRG	Cooling recovery	✔️ Cooling recovery refers to the process of capturing and reusing the cooling energy from exhaust air, condensate, or other waste cooling sources to reduce the load on the HVAC system.

∘₊✧─────✧₊∘ D ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
DIR	Dispersive infrared	Dispersive Infrared is a technology used in gas detection systems where infrared light is split (dispersed) into different wavelengths to identify and measure specific gases based on how they absorb IR light.
DHW	Downhole heat exchanger	A Downhole Heat Exchanger is a geothermal system where a loop of piping is placed deep inside a well to exchange heat with the ground. The fluid inside the pipe absorbs or rejects heat as it circulates through the well.
DTW	Dual temperature water	Dual temperature water refers to an HVAC system that uses two different water temperatures (usually hot water and chilled water) in the same piping network but at different times of the year.

∘₊✧─────✧₊∘ E ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
ECO	Energy conservation opportunity	An Energy Conservation Opportunity is any method, upgrade, or change in an HVAC system that can reduce energy consumption, lower operating cost, or improve efficiency.
ECOP	Economic coefficient of performance	The Economic Coefficient of Performance is a measure that combines the energy efficiency of an HVAC system with its operating cost. It helps evaluate how economically beneficial the system is, not just how much cooling or heating it produces per unit of energy.
ECS	Environmental control system	An Environmental Control System is a setup that maintains and regulates temperature, humidity, air quality, and pressure in a controlled space such as buildings, laboratories, aircraft cabins, or clean rooms.
EER	Energy efficiency ratio	The Energy Efficiency Ratio measures how efficiently an air conditioner or cooling system operates. It is the ratio of cooling output (in BTU/hr) to the electrical power input (in watts) at a specific outdoor temperature.
EIFS	Exterior insulation finishing system	An Exterior Insulation Finishing System is a building wall system that adds insulation on the outside of a building and covers it with a protective, decorative finish. It improves thermal performance and reduces heating and cooling loads.
ETS	Energy thermal storage	Energy Thermal Storage is a system that stores cooling or heating energy during off-peak hours (like night-time) and uses it later during peak demand. Common examples include storing chilled water or making ice at night.
ESPC	Energy saving performance contracting	Energy Saving Performance Contracting is a method where an energy service company upgrades a building’s HVAC and energy systems, and the cost of the upgrades is paid back through the energy savings achieved over time.
ETS	Environmental tobacco smoke	Environmental Tobacco Smoke refers to the combination of smoke exhaled by a smoker and smoke released from a burning cigarette. It is a major indoor air pollutant that affects air quality and health.
ETA	Extract air	Extract air is the indoor air that is removed from a room through ducts or exhaust systems to maintain good air quality and comfort. It usually carries heat, moisture, and contaminants out of the space.
EPA	Efficient Particulate Air filter	An Efficient Particulate Air filter is a high-efficiency air filter designed to capture very small particles, such as dust, pollen, and microorganisms, from the air. It is part of the EN 1822 classification, with performance slightly lower than HEPA filters but still very effective.
EHA	Exhaust air	Exhaust air is the air that is intentionally discharged to the outside of a building by the HVAC system. It usually contains heat, moisture, odors, or contaminants that need to be removed.

∘₊✧─────✧₊∘ F ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
FRP	Fiberglass reinforced plastic piping	Fiberglass Reinforced Plastic piping is a strong, lightweight, and corrosion-resistant pipe made from fiberglass and resin. In HVAC systems, it is used for chilled water, cooling tower water, and chemical-handling applications where corrosion protection is important.

∘₊✧─────✧₊∘ G ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
GCHP	Ground coupled heat pump	A Ground-Coupled Heat Pump uses the stable temperature of the ground to provide heating and cooling. Pipes buried underground exchange heat with the earth, allowing the heat pump to work more efficiently than air-source systems.
GLF’S	Glass load factors	Glass load factors are values used in HVAC design to estimate the amount of heat gain through windows and glass surfaces. They consider sunlight intensity, glass type, shading, orientation, and time of day.
GWHP	Ground water heat pump system	A Groundwater Heat Pump System uses water from an underground well as the heat source (for heating) or heat sink (for cooling). The heat pump extracts or rejects heat to the groundwater and then discharges it back into another well or the same aquifer.
GF	Ground Floor	The Ground Floor is the level of a building that is at the same height as the surrounding ground. It is the floor you enter directly from outside without using stairs or elevators.

∘₊✧─────✧₊∘ H ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
HACCP	Hazard analysis and critical control point	Hazard Analysis and Critical Control Point (HACCP) is a systematic safety method used to identify, evaluate, and control potential hazards in food processing and handling.
HEPA	High Efficiency Particulate Air filter	A HEPA filter is an ultra-efficient air filter used in HVAC systems to remove very tiny particles, including dust, pollen, bacteria, and some viruses. It must capture at least 99.97% of particles as small as 0.3 microns.
HTW	High temperature water	High Temperature Water refers to water heated to a higher temperature range typically above 150°C (300°F) and used in HVAC systems for space heating or industrial processes.
HRS	Heat Recovery System	A Heat Recovery System captures waste heat from exhaust air or processes and uses it to preheat fresh air or water, reducing the load on heating and cooling equipment.

∘₊✧─────✧₊∘ I ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
IGU’S	Insulating glazing units	Insulating Glazing Units are double or triple-layered glass panels separated by an air or gas-filled space to reduce heat transfer and improve energy efficiency.
IAQ	Indoor air quality	Indoor Air Quality refers to the cleanliness, health, and comfort level of the air inside a building. It depends on factors like ventilation, temperature, humidity, and the amount of pollutants present.

∘₊✧─────✧₊∘ L ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
LDA	Laser Doppler anemometers	A Laser Doppler Anemometer is a device that uses laser light to accurately measure the speed and direction of airflow by detecting the movement of tiny particles in the air.
LDV	Laser Doppler velocimeters	A Laser Doppler Velocimeter is an instrument that uses laser beams to measure the velocity of moving air or fluid by detecting frequency changes caused by particle motion.
LPG	Liquefied petroleum gases	Liquefied Petroleum Gas is a flammable fuel gas mainly propane and butane stored in liquid form under pressure.
LLRW	Low level radio active waste	Low-level radioactive waste is waste that contains small amounts of radioactivity. It usually comes from hospitals, laboratories, industries, and nuclear power plants.
LTW	Low temperature water	Low-temperature water is chilled water used in HVAC systems to provide cooling. It is normally cooled to around 6°C to 12°C and then circulated through the building.

∘₊✧─────✧₊∘ M ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
MTW	Medium temperature water	Medium-temperature water is hot water used for heating in large buildings or industrial systems. Its temperature is typically around 90°C to 150°C.
MRT	Mean radiant temperature	Mean Radiant Temperature is the average temperature of all the surfaces around you, such as: walls, ceiling, floor, windows, furniture. These surfaces give off heat (radiation). MRT tells how warm or cool you feel because of that heat.

∘₊✧─────✧₊∘ N ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
NPSH	Net positive suction pressure	NPSH is a value that tells how much pressure is available at the pump inlet to avoid cavitation (bubble formation that damages the pump).
NTC	Negative Temperature Coefficient	NTC is a type of temperature sensor whose resistance drops when the temperature rises used widely in HVAC for accurate temperature control.
NRVU	Non-Residential Ventilation Unit	A Non-Residential Ventilation Unit is a mechanical ventilation system used in commercial, industrial, or public buildings (not homes).
NPO	Noise Protection Ordinance	The Noise Protection Ordinance is a rule or regulation that limits how much noise HVAC equipment is allowed to produce, especially in commercial and residential areas.

∘₊✧─────✧₊∘ O ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
ODA	Outdoor air	Outdoor air is the fresh air taken from outside the building and supplied inside through the HVAC system.

∘₊✧─────✧₊∘ P ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
PTAC	Packaged terminal air conditioner	A PTAC is a self-contained heating and cooling unit that is installed through a wall opening, usually below a window.
PTHP	Packaged terminal heat pump	A PTHP is a self-contained heating and cooling unit installed through a wall opening, similar to a PTAC, but with heat pump technology.
PHE’S	Plate heat exchangers	A Plate Heat Exchanger is a device that transfers heat between two liquids without mixing them. It does this using many thin metal plates stacked together.
PPD	Predicted percentage dissatisfied	Predicted Percentage Dissatisfied is an index used to estimate what percentage of people will feel uncomfortable with the indoor thermal environment (too hot or too cold).
ppm	parts per million	Parts per million is a unit used to measure the concentration of a gas or contaminant in air. It shows how many parts of a substance are present in one million parts of air.
PMV	Predicted Mean Vote	Predicted Mean Vote is a comfort index that predicts how people will feel in an indoor environment, ranging from cold (-3) to hot (+3). It considers factors like temperature, humidity, air speed, clothing, and activity level.
PM	Particulate Matter	Particulate Matter refers to tiny solid or liquid particles in the air, such as dust, smoke, pollen, and soot. These particles can affect indoor air quality and health.

∘₊✧─────✧₊∘ R ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
RTD	Resistance temperature detectors	Resistance Temperature Detectors are temperature sensors that measure temperature by detecting changes in electrical resistance of a metal (usually platinum).
RTS’s	Resistance temperature devices	Resistance Temperature Devices refer to sensors, such as RTDs and thermistors, that measure temperature by detecting changes in their electrical resistance as temperature changes.
RMS	Root mean square	Root Mean Square is a mathematical method used to calculate the effective or average value of a varying electrical signal, such as AC voltage or current.
RTU	Refrigerant transfer units	Refrigerant Transfer Units are systems or equipment used to move, recover, or charge refrigerant between HVAC systems, storage cylinders, or recovery tanks. They ensure safe handling and accurate transfer of refrigerants during service or maintenance.
RVU	Residential Ventilation Unit	A Residential Ventilation Unit is a device used in homes to provide fresh outdoor air while removing stale indoor air. It helps maintain good indoor air quality and can include heat recovery to save energy.
RCA	Recirculation air	Recirculation air is the portion of indoor air that the HVAC system takes from the conditioned space and reuses, mixing it with fresh outdoor air before supplying it back into the room.

∘₊✧─────✧₊∘ S ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
SEER	Seasonal energy efficiency ratio	The Seasonal Energy Efficiency Ratio measures how efficiently an air conditioner or heat pump provides cooling over an entire cooling season. It represents the total cooling output divided by the total energy consumed during that period.
SHGF	Solar heat gain factors	Solar heat gain factors are values used to estimate how much heat from sunlight enters a building through windows, walls, or roofs. They help calculate cooling loads caused by solar radiation.
SWHP	Surface water heat pump	A Surface Water Heat Pump uses water from lakes, ponds, rivers, or reservoirs as the heat source (for heating) or heat sink (for cooling). The stable temperature of the water improves system efficiency.
SVF’S	Synthetic vitreous fibers	Synthetic Vitreous Fibers are man-made fiber materials such as fiberglass, mineral wool, and ceramic fibers, commonly used for thermal insulation, sound control, and fire resistance in HVAC systems and buildings.
SUP	Supply air	Supply air is the conditioned air delivered by the HVAC system into a room or space to maintain comfort, temperature, and air quality.

∘₊✧─────✧₊∘ T ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
TEWI	Total equivalent warming impact	Total Equivalent Warming Impact measures the overall contribution of a refrigeration or HVAC system to global warming, including both: Direct impact from refrigerant leaks (greenhouse gases). Indirect impact from the electricity used to operate the system.
TETD	Total equivalent temperature differential	Total Equivalent Temperature Differential is a calculated value used to estimate heat gain or loss through insulated panels, walls, or enclosures. It accounts for temperature difference, solar heat, and thermal transmission over time.
TETD/TA	Total equivalent temperature differential method with time averaging	The TETD method with time averaging is used to calculate heat gain or loss through insulated surfaces (walls, roofs, cold storage) by considering both temperature differences and solar radiation over time. Time averaging smooths out short-term fluctuations to provide a more accurate estimate of the total thermal load.
TLV	Threshold Limit Value	Threshold Limit Value is the maximum concentration of a chemical or substance in air that most workers can be exposed to without harmful effects during a standard workday.

∘₊✧─────✧₊∘ U ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
UHT	Ultrahigh temperature sterilization	Ultrahigh Temperature sterilization is a process where liquids mainly milk, juices, or other food products are heated to very high temperatures (135–150°C) for a few seconds to kill microorganisms and extend shelf life.
ULPA	Ultra Low Penetration Air filter	An ULPA filter is a high-efficiency air filter that removes at least 99.999% of airborne particles as small as 0.12 microns. It is used in clean rooms, laboratories, and other environments requiring extremely clean air.
UVU	Unidirectional Ventilation Unit	A Unidirectional Ventilation Unit delivers air in a single, uniform direction (usually vertically or horizontally) to minimize turbulence and prevent contamination in controlled spaces.

∘₊✧─────✧₊∘ V ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
VOC	Volatile organic compound	Volatile Organic Compounds are chemicals that easily evaporate into the air from paints, solvents, cleaning products, and building materials. High levels of VOCs can affect indoor air quality and health.
VRT	Virgin rock temperature	Virgin Rock Temperature refers to the natural, undisturbed temperature of the ground or rock before any geothermal system or drilling activity alters it. It is important for designing geothermal heat pump systems.

∘₊✧─────✧₊∘ W ∘₊✧─────✧₊∘

Abbrev.,	Full Form	Notes
WSHP	Water source heat pump	A Water Source Heat Pump uses water from a lake, river, well, or closed-loop system as a medium to transfer heat for heating or cooling a building. It extracts heat from the water in winter and rejects heat to the water in summer.
WBGT	Wet bulb globe temperature	Wet Bulb Globe Temperature is an index that measures heat stress on humans, combining temperature, humidity, wind speed, and radiant heat. It’s commonly used to assess safe working or exercise conditions.
WHU	Waste Heat Utilisation	Waste Heat Utilisation is the process of capturing and reusing heat that is normally lost from industrial processes, exhaust gases, or HVAC systems to perform useful work, like heating water or generating power.

🏁 Conclusion

• This complete HVAC abbreviation guide provides a quick and reliable reference for understanding the most commonly used terms in heating, ventilation, and air-conditioning systems. 
• Whether you're working on system design, maintenance, installation, or building automation, knowing these abbreviations will make your work faster, clearer, and more accurate.
• Keep this list bookmarked it is a valuable resource for both beginners and experienced professionals in the HVAC industry.

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