FAQ Glossary

A Glossary of HVAC, Heating & Air Conditioning Terms


Aerosol: An assemblage of small particles suspended in air

Agglomeration: The formation of larger airborne particles by the collision of two or more smaller particles

Air Flow: Quantity of air passing through a given cross sectional area at a stated velocity

Allergen: A biological or chemical substance that causes an allergic reaction

ASHRAE: American Society of Heating, Refrigeration and Air Conditioning Engineers

CADR: Clean air delivery rate

CFM: Cubic feet per minute

Dander: Small scales of animal skin

Dehumidify: To remove water vapor from an air stream

Dust: An aerosol of particles of any solid material

ERV: Energy Recovery Ventilator. A device that brings fresh air into the home, exhausting the same volume of air from the home

FPM: Feet per minute

HEPA: High Efficiency Particulate Air. These filters must have an efficiency of 99.97%

Humidifier: Device used to add moisture to air

IAQ: Indoor Air Quality

Ozone: A gas whose molecules are composed of three oxygen atoms. It is significantly toxic

Particles: Very small solid or liquid substances that are light enough to float in air

PPM: Parts per million

Radon: Radioactive pollutants which originate from rock, soil or groundwater

ULPA: Ultra Low Penetration Air. These filters have efficiencies of 99.999%

VOC: Volatile Organic Compound. VOCs are typically emitted from housekeeping and maintenance products