Air distribution system:
includes all building elements (duct systems, air handling units, cavities of the building structure and mechanical closets) through which air is delivered to or from the conditioned spaces.

Air handler:
the fan unit of a furnace and the fan-coil unit of a split-system, packaged air conditioner or heat pump.

Biomass:
renewable source of energy that has been stored as plant and animal material; producing fuels from living materials or decayed waste materials; examples: manure, wood, compost, ethanol from corn, methane from landfills.

Biogas from Crops:
farmers can use crop waste or entire crops that can be gasified or burned as fuel.

Btu (British thermal unit):
the IP standard unit for measuring the amount of energy consumed by a process, the amount of energy transferred from one location to another, or the amount of embodied energy (such as the heat content of fuel); it is the amount of heat energy necessary to raise the temperature of one pound of water one degree Farenheit.

Btu/h (British Thermal Units per hour):
one of the two (watts is the other) standard units of measure (IP System) for the rate at which energy is used by equipment or the rate at which energy moves from one location to another.

Building air tightness:
a measurement of a structure’s resistance to the uncontrolled leakage of air and the water vapor it contains (see infiltration).

Building envelope:
the sections of the building that enclose conditioned or inside spaces through which heat transfer may occur to or from the outside, including the floor, walls, windows, doors, ceiling and roof.

Building performance:
how well a building provides an energy efficient, comfortable and productive space.

Coal:
a black rock-like solid fossil fuel found underground. Burned or gasified to produce electricity.

COP (coefficient of performance):
for a heat pump- the ratio of the rate of heat delivered to the rate of energy input, in consistent units, for a complete heat pump system under designated operating conditions.

Celsius (C):
temperature scale used in the metric system in which water freezes at 0o and boils at 100^o.

CFL (compact fluorescent lamp):
a fluorescent lamp that is packaged as a bulb similar in size to a typical incandescent lamp.

Conduction:
heat transfer mechanism that occurs when two materials of different temperature are in direct contact or when there is a difference in temperature within a single material- the warmer material or side conducts it’s heat to the cooler one.

Conductance:
measurement of how easily heat energy can move through material.

Convection:
heat transfer mechanism that occurs when a material comes in contact with air (or other gas or liquid) - a warmer material heats up the air adjacent to its surface, and in turn the warmer air rises and is replaced with more cooler air.

Duct air tightness:
a measurement of an air duct system’s resistance to the uncontrolled leakage of air and the water vapor it contains.

Duct leakage:
unintentional air loss from or gain to (via holes, cracks etc.) an air distribution system, or the rate at which the unintentional air gain or loss occurs.

Efficacy:
ratio of light output from a lamp to the electric power it consumes. Efficacy is measured in lumens per watt (LPW).

Energy audit:
a site inventory and descriptive record of features impacting the energy use in a building; it includes building component descriptions, energy using equipment and appliance descriptions, and all energy features.

Energy source:
object or material that produces energy by changing it from one source to another.

Equipment Efficiency:
the ratio of useful energy output (at the point of use) to the energy input in consistent units for a designated time period, expressed in percent.

Fahrenheit:
measurement scale on which under standard atmospheric pressure the boiling point of water is at 212o above the zero of the scale, the freezing point is at 32o above zero.

Fluorescent:
commonly used lighting in commercial and institutional facilities; a fluorescent lamp uses electricity conducted through mercury and inert gases. Typical fluorescent lamps are manufactured as 2 to 8 foot long tubes (4 foot being the most common) or as CFLs.

Foot candle:
a lumen of light evenly distributed over a one square foot (0.09 square meter) area.

Fossil fuels:
nonrenewable energy sources that come from fossilized plants and animals and cannot be replenished; examples: coal, oil, natural gas.

Geothermal:
renewable source of energy from the internal heat in the core of the earth;
examples: hot springs, steam, volcanoes.

Geothermal energy:
harnessing heat and steam generated below earth’s surface.

Heat energy:
the capacity to increase the molecular activity of a substance and thereby increase its temperature.

Heat pump:
A mechanical refrigeration-cycle system with has been designed to accomplish space heating, water heating or both and, when the evaporator and condenser effects are reverse, may be used for space air conditioning or water chilling.

Heat transfer:
how heat energy is transferred via conduction, convection, and radiation.

HSPF (Heating Season Performance Factor):
a standard measurement of the efficiency of an electric heat pump. The total heating output of a heat pump during its normal annual usage period for heating in Btu divided by the total electric power input in watt-hours during the same period.

HVAC:
heating, ventilation and air conditioning.

HVAC system:
the equipment, distribution network, and terminals that provide the processes of heating, ventilating and/or air conditioning to a building.

Hydropower:
renewable source of energy that comes from water and is harnessed to produce electricity.

Incandescent:
the most common type of home lighting; a standard incandescent lamp uses an electric current to heat a small coil of tungsten filament inside a glass bulb to produce light.

Infiltration:
The uncontrolled leakage of air and the water vapor it contains through holes (cracks etc.) in the building envelope caused by pressure differences between the indoors and outside air.

Infrared light:
invisible radiation or light contiguous to red in the visible spectrum; light energy we feel as heat.

Insulation:
material mainly used to retard the flow of heat.

Kilowatt (kW):
a measure of electricity, equal to 1000 watts.

Lamp:
a lighting industry term for an electric light bulb, tube, or other lighting device.

Load:
a device to which power is delivered.

Lumen:
a measure of light output from a lamp (often called a bulb or tube). All lamps are rated in lumens. For example, a 100-watt incandescent lamp produces about 1750 lumens.

Natural Gas:
invisible, odorless fossil fuel gas found underground. Burned or gasified to produce heat and electricity.

Nonrenewable energy source:
source of energy that is either unable to be replaced naturally or is naturally replaced very slowly; examples: fossil fuels (coal, oil, natural gas, petroleum, propane) and nuclear fuels (uranium).

Nuclear energy:
splitting radioactive uranium atoms to create heat energy.

Nuclear fission:
atoms that form Uranium are split apart and release heat energy which produce steam for electric turbines.

Orientation:
set in any definite position with reference to the points of the compass.

Photovoltaic (PV):
the effect of producing electric current using light
photo: light
voltaic: producing direct electric current by chemical action.

Photovoltaic (PV) cell:
device that converts solar energy directly into electricity.

Plenum:
an air compartment or chamber of an air distribution system to
which one or more ducts are connected.

Propane:
a gaseous hydrocarbon found in natural gas and petroleum and used as fuel.

Radiation:
heat transfer mechanism that occurs when two materials are separated by air or a vacuum- the warmer surface emits or radiates across the air space to the cooler surface.

Radiant barrier:
surface (typically a layer of aluminum foil) placed in an airspace to block radiant heat transfer between a heat-radiating surface and a heat-absorbing surface.

Reflectance:
the ratio of the light reflected by a surface to the light falling upon it.

Renewable energy source:
source of energy that is virtually inexhaustible and is naturally and quickly replenished; examples: solar, wind, hydropower (water), geothermal, and biomass.

SEER (Seasonal Energy Efficiency Ratio):
a standard measurement of the seasonal cooling efficiency of an electric air conditioner. Specifically, the estimated total cooling of a central air conditioner in Btu’s during its normal usage period for cooling (not to exceed 12 months) divided by the total electric energy input in watt-hours during the same period.

Simple payback:
number of years needed to pay for energy efficiency improvements using the energy cost savings that accrue annually from those improvements- the initial cost of the improvements divided by the annual energy cost savings from those improvements.

Solar energy:
energy derived from the sun.

Solar thermal:
sun's heat is collected to heat domestic or pool water or create steam for electricity using concentrators.

Temperature:
a method of measuring the affect of heat energy on a substance.

Uranium:
a heavy silvery-white radioactive metallic element used in nuclear fuels and weapons.

Ventilation:
the process of supplying or removing air, by natural or mechanical means, to or from any space. Such air may or may not have been conditioned.

Waste-to-Energy:
includes landfill methane and burning or gasifying trash to produce electricity.

Watt:
the SI (System International) unit of power or rate of doing work; also the rate at which energy is consumed by equipment or the rate at which energy moves from one location to another.

Wind energy:
renewable source of energy that uses wind to turn a windmill.