absolute humidity
absorbed glass mat
absorber
absorption
absorption chiller
absorption cooling
absorption heat pump
absorption refrigeration
absorptivity
accumulator
acid rain
acoustical tile
active solar energy system
adobe
advanced house framing techniques
advanced windows
adze
aerosol
aerosol duct sealing
aggregate
air
air admittance valve
air barrier
air change rate
air conditioner
air conditioning
air conditioning intensity
air hammer
air leakage
air mass
air pollutant
air pollution
air pollution control
air retarder/barrier
air sealing
air-based collector
air-source heat pump
airtight drywall approach (ADA)
air-to-air heat pump
albedo
alcohol
algae
algal bloom, harmful
alkaline battery
alkaline fuel cell
alternating current
alternative energy sources
alternative fuels
ammonia
amorphous semiconductor
ampere (A)
ampere-hour (Ah)
anaerobic digester
anaerobic digestion
andirons
anemometer
angstrom
anode
anthracite
anvil
appliances and home electronics
apron
aquaculture
aquifer
arcology
Arkiane stoves
artesian well
atmosphere
atrium
attic acess insulation
attic fan
attic insulation
attic vent
audit (energy)
auger
aviation snips
awl
awning
axial flow compressor
azimuth