Absolute humidity - correct answer ✔Air moisture content expressed in
grains (or pounds) of water vapor per pound of dry air.
Absorptance - correct answer ✔The ratio of a solar energy absorbed to
incident solar. Also called absorptivity.
Absorption - correct answer ✔A solid material's ability to draw in and hold
liquid or gas.
Air barrier - correct answer ✔Any part of the building shell that offers
resistance to air leakage. The air barrier is effective if it stops most air
leakage. The primary air barrier is the most effective of a series of air barriers.
Air changes at 50 pascals (ACH50) - correct answer ✔The number of times
that the complete volume of a home is exchanged for outside air when a
blower door depressurizes the home to 50 pascals.
Air conditioning - correct answer ✔Cooling buildings with a refrigeration
system. More generally means both heating and cooling.
Air exchange - correct answer ✔The total building air exchanged with the
outdoors through air leakage and ventilation.
Air handler - correct answer ✔A steel cabinet containing a blower with
cooling and/or heating coils connected to ducts.
, Asbestos - correct answer ✔A material made of brittle mineral fibers that
damage lungs and other bodily tissues.
Annual fuel utilization efficiency (AFUE) - correct answer ✔A laboratory-
derived efficiency rating for heating appliances which accounts for chimney
losses, jacket losses, and cycling losses.
Annual return - correct answer ✔The yearly savings divided by the initial cost
needed to achieve the savings, expressed as a percent.
Backdrafting - correct answer ✔Continuous spillage of combustion gases
from a combustion appliance.
Backdraft damper - correct answer ✔A damper, installed near a fan, that
allows air to flow in only one direction
British thermal unit (Btu) - correct answer ✔The quantity of heat required to
raise the temperature of one pound of water one degree Fahrenheit.
Capillary action - correct answer ✔The ability of water to move through
materials, even upward against gravity, through small tubes or spaces.
Carbon dioxide - correct answer ✔One of two main products of complete
combustion of a hydrocarbon(Do you recall the other?)
Combustion efficiency - correct answer ✔Synonymous with fuelburning
efficiency or steady-state efficiency. Usually means the latter.