2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Solar ROI
Solar ROI (Return on Investment) is the percentage return generated…
Solar Roof Tile
A solar roof tile is a photovoltaic module shaped and…
Solar Self Consumption
Solar self consumption is the practice of using solar energy…
Solar Series Connection
Solar series connection links photovoltaic modules positive-to-negative to increase voltage…
Solar Shingle
A solar shingle is a small-scale photovoltaic module designed to…
Solar Space Heating
Solar space heating uses solar thermal collectors to capture sunlight…
Solar Storage Tank
A solar storage tank is an insulated vessel that stores…
Solar String
A solar string is a series of photovoltaic modules electrically…
Solar Tax Credit
A solar tax credit is a government incentive that allows…
Solar Thermal Array
A solar thermal array is a group of interconnected solar…
Solar Thermal Cooling
Solar thermal cooling uses solar heat to power cooling systems…
Solar Thermal Fluid
Solar thermal fluid, also called heat transfer fluid or HTF,…
Solar Thermal System
A solar thermal system captures heat directly from sunlight to…
Solar Tracking System
Solar tracking systems automatically adjust panel orientation throughout the day…
Solar Water Heater
A solar water heater uses thermal energy from the sun…
Solar Wire
Solar wire is specially formulated electrical conductor rated for direct…
Soldering
Soldering is the process of joining copper tubing and fittings…
Solenoid Valve
A solenoid valve is an electromechanical device that uses an…
Solid Desiccant
Solid desiccant materials are porous minerals or composite substances that…
Sorption Isotherm
A curve relating the equilibrium moisture content of a hygroscopic…
Sound Attenuator
A sound attenuator is a lined duct section or silencer…
Sound Baffle
A sound baffle is an engineered acoustic element designed to…
Sound Level Meter
A sound level meter is a calibrated electronic instrument that…
Source Control
Source control eliminates or reduces indoor air pollutants at their…
Source Energy
Source Energy represents the total raw energy consumed at power…
Specific Enthalpy
The enthalpy of moist air referenced to a unit mass…
Specific Heat
Specific heat is the amount of thermal energy required to…
Specific Leakage Rate
Air leakage expressed as cubic feet per minute per square…
Specific Volume
Specific volume is the volume occupied by one pound of…
Spiral Duct
Spiral duct is a round ductwork constructed by spirally winding…
Split System
A split system is an HVAC configuration that divides its…
Split System Installation
Split system installation involves connecting an outdoor condenser unit to…
Splitter Damper
A curved or flat blade installed at the junction of…
Spore Trap
A spore trap is a passive or active air sampling…
Spot Exhaust
Spot exhaust is a localized ventilation system that removes moisture,…
Spot Monitoring
Spot monitoring is the collection of air quality measurements at…
Spray Foam Insulation
Spray foam insulation is a polyurethane or polyisocyanurate material applied…
Spring Isolator
A spring isolator is a mechanical device using compressed steel…
Spring Return Actuator
A spring return actuator uses an internal spring mechanism to…
Spring Startup
Spring Startup is the pre-season service performed before cooling season…
SREC
An SREC (Solar Renewable Energy Certificate) is a tradable credit…
Stack Effect
The stack effect describes the natural movement of air through…
Stack Effect Pressure
The pressure difference across a building envelope driven by the…
Stack Temperature
The temperature of flue gases measured at the appliance flue…
Stainless Steel Pipe
Stainless steel pipe is a corrosion-resistant tubing made from steel…
Standby Mode
Standby Mode is a low-energy operational state where HVAC components…
Standing Column Well
A geothermal open-loop variant that draws water from and returns…
Standing Pilot
A standing pilot is a small, continuously burning flame that…