- AC
- ACCA
- Access Chamber
- Accessible
- A-Coil
- AC or DC
- Acoustical
- AFUE
- AGA
- AHRI
- Air Break
- Air cleaner (also Air Filtration System)
- Air Conditioner
- Air Filtration System (also Air Cleaner)
- Air flow volume
- Air Gap
- Air handler
- ASHRAE
- Authority
- Backflow
- Backpressure
- Backsiphonage
- Backwater Valve
- Black Water
- BTU
- BTUH
- Building Drain
- Building Sewer
- Building Subdrain
- Burner
- Burner Orifice
- Burner (sealed combustion)
- CADR Clean Air Delivery Rate (CADR)
- Capacity
- Celsius
- Certified Matched System
- CFM
- Charge
- Check Valve
- Cistern
- Cleaning Eye
- Colour Marking
- Combined Building Drain
- Combined Building Sewer
- Comfort™ coil (also evaporator coil or indoor coil)
- Compressor
- Condensate
- Condenser coil (or outdoor coil)
- Condenser fan
- Conservation
- Contactor
- Corrosion
- Crankcase heater
- Cross-Connection
- CSA
- Damper
- DB (Decibels)
- DC
- Defrost
- Degree-day
- Dehumidifier
- Diffuser
- Disinfection
- DOE
- Downflow furnace
- Downpipe or Downspout
- Drain
- Drainage System
- Drain Cock
- Drain pan
- Dry bulb temperature
- Dry bulb thermometer
- Dual Compressors
- Dual System
- Ductwork
- DX
- Ecologic
- EER
- Electrolysis
- Electronic Air Cleaner (EAC)
- EPA
- Evaporator coil (also Comfort™ Coil or Indoor coil)
- Expansion valve
- Fahrenheit
- Fan
- Filter
- Fixture
- Fixture Unit
- Flammable Waste
- Float Valve
- Flue
- Flushometer Valve
- Frost Protection
- Furnace
- Fuse
- GAMA
- Gas furnace heat exchanger
- Grease Interceptor
- Grease Trap
- Green Water
- Greywater
- Heat exchanger
- Heat gain
- Heating coil
- Heat loss
- Heat pump
- Heat transfer
- 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
- Indirect Connections
- Indoor coil (also Comfort™ Coil or evaporator coil)
- Indoor/Outdoor system (also split system)
- Industrial Waste
- Inspection Chamber
- Interceptor
- Inverter Compressor
- Kilowatt (kW)
- Latent heat
- Liquid Waste
- Load calculation
- Manhole
- Media
- Mixing Valve
- NATE
- NEC
- Negative Pressure
- NEMA
- Non-Return Valve
- OEM
- Oil Trap
- Operating cost
- Orifice
- Outdoor coil (also Condenser coil)
- Overflow System
- Packaged system (or Packaged unit)
- Packaged unit (or Packaged system)
- Payback analysis
- pH
- Plumbing Fixture
- Potable Water
- Pressure Reduction Valve
- Pressure Relief Valve
- PSI
- PSIA
- PSIG
- PVC
- Reciprocating compressor
- Reclaimed Water
- Reclaiming
- Recycling
- Refrigerant
- Refrigerant charge
- Refrigerant lines
- Roof Drainage
- Safe or Potable Drinking-Water
- Sanitary Building Drain
- Sanitary Building Sewer
- Sanitary Sewer
- SEER
- Self-contained system
- Sensible heat
- Sensor
- Setpoint
- Sewage
- Sewer
- Sewerage
- Sewer System
- Spine-Fin™ coil
- Split system (also indoor/outdoor system)
- Stop Valve
- Storm Drain
- Storm Water Drainage
- Subsoil Drain
- Temperature and Pressure Relief Valve
- Thermostat
- Thermostatic expansion valve
- Ton
- Trap
- Two-stage compressor
- Two-stage heating/Two-stage cooling
- U-Factor
- UL
- Upflow furnace
- Vacuum
- Vent
- Volt
- Voltage
- Waste
- Wastewater
- Water Closet
- Watt
- Wet Bulb Thermometer
- Zoning
- Zoning System