Glossary of Terms
Glossary of Terms
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
13 SEER
This is the new minimum efficiency standard (effective January 2006) for an
air conditioner or heat pump. All new units must now meet this
standard. Previously manufactured equipment may be used, sold, and
installed. SEER is defined later.
ACCA
The Air Conditioning Contractors of
AIR HANDLING UNIT
Equipment with a heating element and/or cooling coil and other components in a
cabinet or casing.
ARI
Air-Conditioning and Refrigeration Institute, a
non-profit, voluntary organization composed of heating, air conditioning and
refrigeration manufacturers. ARI publishes
standards for testing and rating heat pumps and air conditioners.
BALANCING or AIR BALANCING
Adjusting an air conditioning system so that the right amount of air is delivered
to the right places in your home in order to achieve the right heating or
cooling effect.
BTU
British Thermal Unit, the measurement
of heating and air conditioning capacity. A BTU is the amount of heat
that must be added to one pound of water to raise its temperature one degree
Fahrenheit.
CFC
Chlorofluorocarbons, used as a refrigerant in air
conditioners and heat pumps, linked to the depletion of the ozone layer.
COP
Coefficient of performance, an efficiency ratio that
compares the amount of heat delivered to the amount of energy used. As
with MPG on a car, the higher the score the more energy efficient the equipment
is.
COIL
A heating or cooling element made of pipe or tubing, usually with plates
or fins.
COMMISSIONING
The final step in installing a heating or air
conditioning system. Every component is checked and tested for compliance
with codes, ACCA manuals, manufacturer requirements, and occupant needs. After
commissioning, the technician will: provide documentation of testing, provide
all equipment manuals, and show the homeowner how to operate the system.
CONDENSER (HEAT EXCHANGER)
The outside unit of a heating or air conditioning
system. Here the refrigerant condenses from a gas to a liquid and hot or cold
air from the building is released to the outside.
DEHUMIDIFIER
A device that removes excess moisture from the air.
DOE
The
DUCT
Conduits used to carry air. They can be round or
rectangular, sheet metal or fiberglass or vinyl tubes. In air
conditioning systems they carry air from the home to the air conditioning
system or furnace and back to the home.
ERV
Energy Recovery Ventilator, a machine that draws fresh
air into the home and exhausts stale air from the home. It uses a process
to preheat or pre-cool (depending on the season) to reduce energy costs
associated with conditioning the air.
ENERGY STAR®
A government supported branding used to identify
energy efficient products. The branding was developed by the
EPA
The
FAN COIL
See AIR HANDLING UNIT
FURNACE
A self-contained heating unit that is designed to
deliver heated air to a home.
GAMA
Gas Appliance Manufacturing Association is a national
trade association serving the interests of manufacturers of gas, oil, and
electric appliances and equipment, components and related products used in
residential, commercial, and industrial applications.
HCFC
Hydrochlorofluorocarbons, used as a refrigerant in air conditioners and heat pumps. HCFCs were thought to contribute to the
depletion of the earth’s ozone layer.
HEAT EXCHANGER
1. The part of a
furnace that transfers heat from burning fuel to the air used to heat your
home. Also, from a boiler to water for hydronic
heating.
2. A device, such as a condenser or evaporator, in which heat is added or
removed in order to heat or cool your home.
HEAT PUMP
A single refrigeration system designed to provide both heating and
cooling. Compare to a furnace and an air conditioner, separate units that
only heat or cool.
HRV
Heat Recovery Venilator,
a machine that brings fresh air into a home through a process that preheats the
air so it has less impact on your utility bill.
HFC
Hydroflorocarbon, used as a refrigerant in air conditioners and heat pumps. It has
little or no effect on the ozone layer.
HSPF
Heating Seasonal Performance Factor, an equipment
efficiency rating. As with MPG on a car, the higher the rating the more
fuel efficient the equipment is.
HUMIDIFIER
A device that adds moisture to warm air for your home.
HVAC
Heating, ventilating, and air conditioning
HVACR
Heating, ventilating, air conditioning, and refrigeration
INFILTRATION
Air that enters your home through holes, gaps, and
cracks, (e.g., plumbing or electrical holes, the heating and air conditioning
system, doors, and windows).
IAQ
Indoor air quality
LATENT HEAT
The energy that suspends moisture vapor in the air.
LOAD CALCULATION
A mathematical determination of how much cooling and
heating (BTUs) an HVAC system must deliver for occupant safety and comfort.
It is based on a variety of factors: square footage, building
orientation, number of occupants, size and placement of rooms, number and size
of windows and doors, amount of insulation, number of floors, and climate.
MANUAL D®
An ACCA procedure covering the proper design,
installation, maintenance, and repair of ductwork.
MANUAL J®
An ACCA procedure covering the method for calculating
heating and cooling requirements (load calculation) for single-family detached
homes and mobile homes.
MANUAL RS®
An ACCA publication covering the design, installation,
and commissioning of a residential HVAC system.
MATCHED SYSTEM
An air conditioner or heat pump system composed of
equipment that has been certified by ARI to work together to deliver the
specified heating and cooling capacity at the stated efficiency rating.
MOLD
A natural byproduct of the fungi family that thrives
when organic substances and water combine under certain circumstances.
Mold reproduces via spores that can remain dormant, yet viable, for
years. Many molds are beneficial. For example, they are the “bleu”
in bleu cheese, and we use them to make wine, penicillin, and antibiotics.
However, some molds can cause health problems.
NATE
North American Technician Excellence, the nonprofit
organization that tests and certifies HVACR technicians.
PMA
Planned maintenance agreement, which provides regular
maintenance of your HVACR system. Most ACCA member contractors offer PMAs, although they may use different names for them, such
as Maintenance Inspection Agreement, Planned Service Agreement, Energy Service
Plan, etc.
R-22
A refrigerant containing chlorine used in air
conditioning systems. The EPA has mandated that R-22 cannot be manufactured
after 2010 because it has been linked to the depletion of the ozone layer and
global warming. Most commonly referred to by its trademarked name, Freon.
R-410A
The refrigerant that replaces R-22. It does not
contain chlorine and is not hazardous to the environment.
REFRIGERANT
A fluid that absorbs heat at low temperatures and
rejects heat at higher temperatures.
REFRIGERANT CHARGE (or, “charging the refrigerant”)
The procedure an HVACR technician performs to ensure
that the system has enough of the right kind refrigerant for peak operating
performance.
RELATIVE HUMIDITY (RH)
The percent of moisture actually in the air compared
to the maximum amount of moisture the air can hold at that temperature.
RETURN, RETURN AIR, RETURN SIDE
The path the air takes to get to an air-handling unit or furnace so it can
be cooled or heated. It is the “return” path. The return side
should be “balanced” with the supply side to ensure proper air flow and
comfort.
SEER
Seasonal Energy Efficiency Ratio, an equipment
efficiency rating that measures how much energy it takes to cool the air.
As with MPG on a car, the higher the number the more
efficient the unit.
SENSIBLE HEAT
The temperature of the air. This type of heat is measured with a thermometer.
SPLIT SYSTEM
A two-component heating and cooling (heat pump) or cooling
only (air conditioner) system. The condensing unit is installed outside, the air handling unit is installed inside
(preferably in conditioned space). Refrigerant lines and wiring connect
them together.
SUPPLY or SUPPLY SIDE
The part of an HVAC system that takes (supplies) the conditioned air from
the air-handling unit or furnace to your home. The supply side should be
“balanced” with the return side to ensure proper air flow and comfort.
-Z-
ZONES, ZONED SYSTEM, ZONING
A single HVAC system that can meet different heating and cooling needs in
different areas (zones). Each zone of a home has its own thermostat with
which it can regulate the temperature and humidity in its area. One
“zoned air conditioner” could be set for a high temperature in one zone and for
a lower temperature in the other zone. Zone systems have two or more
zones.
