2,400+ Definitions

HVAC GLOSSARY

Every HVAC term, acronym, and industry phrase — defined in plain English.

All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Reversing Valve Failure
Reversing valve failure occurs when the component that switches between…
Revit MEP
Revit MEP is Autodesk’s specialized BIM software designed for mechanical,…
Rigid Foam Board
Rigid foam board is a lightweight sheet insulation material manufactured…
Riser Diagram
A riser diagram is a vertical representation of piping or…
Rolling Brownout
A Rolling Brownout is a temporary, rotating reduction in electrical…
Roof Mount Solar
Roof mount solar refers to photovoltaic panels installed directly on…
Roof Reflectance
Roof reflectance, also called albedo, measures the percentage of solar…
Rooftop Equipment
Rooftop equipment includes HVAC units, cooling towers, air handling units,…
Rooftop Unit
A Rooftop Unit (RTU) is a self-contained heating, ventilation, and…
Rooftop Unit (RTU) Heat Exchanger
The gas-to-air heat exchanger inside a packaged rooftop unit through…
Room Air Cleaner
A room air cleaner is a portable or wall-mounted device…
Room Air Distribution
Room air distribution describes the movement and mixing patterns of…
Room Condition Line
A line on the psychrometric chart connecting the room design…
Room Occupancy Detection
Room occupancy detection uses sensors to identify whether spaces are…
Rotary Heat Exchanger
A slowly spinning wheel or drum that transfers heat between…
Rotating Vane Anemometer
A rotating vane anemometer measures air velocity through a calibrated…
Roughness Factor
A parameter representing the surface texture of duct walls used…
Round Duct
Round duct is cylindrical metal tubing used to distribute conditioned…
RTD Sensor
An RTD (Resistance Temperature Detector) sensor measures temperature by monitoring…
Rubber Isolator
A rubber isolator is a resilient elastomer element that absorbs…
Run Capacitor
An AC electrolytic or film capacitor that remains in the…
Run-Around Coil System
A heat recovery system in which two separate coil-and-fan assemblies…
Runaround Coil
A runaround coil system consists of two heat exchanger coils…
Runway Damper
A runway damper is a fire damper engineered to compartmentalize…