- A-Coil
- AC
- AC or DC
- ACCA
- Acoustical
- AFUE
- AGA
- AHRI
- Air cleaner (also Air Filtration System)
- Air Conditioner
- Air Filtration System (also Air Cleaner)
- Air flow volume
- Air handler
- ASHRAE
- BTU
- BTUh
- Burner
- Burner Orifice
- Burner (sealed combustion)
- CADR Clean Air Delivery Rate (CADR)
- Capacity
- Celsius
- Certified Matched System
- CFM
- Charge
- Comfort™ coil (also evaporator coil or indoor coil)
- Compressor
- Condensate
- Condenser coil (or outdoor coil)
- Condenser fan
- Contactor
- Crankcase heater
- CSA
- Damper
- DB (Decibels)
- DC
- Defrost
- Degree-day
- Dehumidifier
- Diffuser
- DOE
- Downflow furnace
- Drain pan
- Dry bulb temperature
- Dry bulb thermometer
- Dual Compressors
- Ductwork
- DX
- Ecologic
- EER
- Electronic Air Cleaner (EAC)
- EPA
- Evaporator coil (also Comfort™ Coil or Indoor coil)
- Expansion valve
- Fahrenheit
- Fan
- Filter
- Flue
- Furnace
- Fuse
- GAMA
- Gas furnace heat exchanger
- Heat exchanger
- Heat gain
- Heat loss
- Heat pump
- Heat transfer
- Heating coil
- HEPA filter
- Hertz
- Horizontal flow
- HSPF
- Humidifier
- Humidistat
- Humidity
- Humidity, absolute
- Humidity, relative
- HVAC
- Hybrid heat (also Hybrid System)
- Hybrid system (also Hybrid Heat)
- Ignition
- Indoor coil (also Comfort™ Coil or evaporator coil)
- Indoor/Outdoor system (also split system)
- Inverter Compressor
- Kilowatt (kW)
- Latent heat
- Load calculation
- Media
- NATE
- NEC
- NEMA
- OEM
- Operating cost
- Orifice
- Outdoor coil (also Condenser coil)
- Packaged system (or Packaged unit)
- Packaged unit (or Packaged system)
- Payback analysis
- PSI
- PSIA
- PSIG
- PVC
- Reciprocating compressor
- Reclaiming
- Recycling
- SEER
- Self-contained system
- Sensible heat
- Sensor
- Setpoint
- Spine-Fin™ coil
- Split system (also indoor/outdoor system)
- Thermostat
- Thermostatic expansion valve
- Ton
- Two-stage compressor
- Two-stage heating/Two-stage cooling
- U-Factor
- UL
- Upflow furnace
- Vacuum
- Volt
- Voltage
- Watt
- Wet Bulb Thermometer
- Zoning
- Zoning System