Tom's Mechanical, Inc.

GLOSSARY OF TERMS

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.

Air Balancing -

Adjusting an air conditioning system so that the right amount of air is delivered to the right places in a building 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 -

Chloroflourocarbons, 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.

Condenser -

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.

Condenser Coil -

Part of the condensing unit which converts refrigerant from gas back into liquid form. Transfers heat from the refrigerant to the outside air.

Dehumidifier -

A device that removes excess moisture from the air.

DOE -

Department of Energy, the federal agency that sets industry efficiency standards.

Duct -

Conduits used to carry air. They can be round or rectangular, sheet metal or fiberglass or vinyl.

Electronic Air Cleaner -

An electronic device that provides air filtration by drawing magnetized particles on to a collector plate.

Energy Recovery Ventilator -

A machine that draws fresh air into the building and exhausts stale air. It uses a process to precondition the incoming air to reduce energy costs.

Emergency Heat -

The auxiliary or emergency heat, usually electrical resistance heat, provided at temperatures below a heat pump's temperature capability.

Energy Star -

A government supported branding used to identify energy efficient products. The branding was developed by the Department of Energy and the Environmental Protection Agency.

Evaporator Coil -

The portion of a heat pump or air conditioning system that functions as the transfer point for warming or cooling indoor air.

Furnace -

A self-contained heating unit that is designed to deliver heated air to a building.

HCFC -

Hydrochloroflourocarbons, used as a refrigerant in air conditioners and heat pumps. HCFC's were thought to contribute to the depletion of the ozone layer.

Heat Exchanger -

The section of a furnace that transfers heat from burning fuel to the air used to heat a building. (Can also refer to any device which adds or removes heat.)

Heat Pump -

A refrigeration system designed to provide both heating and cooling by reversing the flow of refrigerant through the system.

HRV -

Heat Recovery Ventilator, a machine that brings fresh air into a building 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 a building.

HVAC -

Heating, Ventilating and Air Conditioning

HVAC-R -

Heating, Ventilating, Air Conditioning and Refrigeration

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 an HVAC system must deliver for occupant safety and comfort. It is based on a variety of factors: square footage, building orientation, occupant load, size and placement of rooms, number and size of windows and doors, amount of insulation, number of floors and climate.

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.

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. However, some molds can cause health problems.

Package Unit -

A heating and cooling system that has all of the components completely encased in one unit. These systems are typically used for commercial and industrial applications and are often mounted on the roof.

R-22 -

A refrigerant containing chlorine used in air conditioning systems. The EPA has mandated that R-22 cannot be manufactured after 2010 because ti has been linked to the depletion of the ozone layer. It is 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. Frequently known by its trademarked name, Puron.

Refrigerant -

A fluid that absorbs heat at low temperatures and rejects heat at high temperatures.

Relative Humidity -

The percentage of moisture actually in the air compared to the maximum amount of moisture the air can actually hold at a given temperature.

Return -

The path the air takes to return from a building to the furnace or air handler to be heated or cooled. An air conditioning system must have the correct amount of return to function properly.

SEER -

Seasonal Energy Efficiency Ratio, an equipment efficiency rating that measures how much energy it takes to cool the air. As with MPG in a car, the higher the number, the more efficient the unit is. As of 2006, the minimum SEER rating allowed for new residential equipment is 13.0.

Split System -

An air conditioner or heat pump that has compnaents in two locations. One part of the system (evaporator coil) is located indoors and the other part (condenser) is located outside. Split systems are the most common systems used in homes.

Supply -

The part of an HVAC system that takes the conditioned air from the air handler or furnace into the building areas which are to be heated or cooled.

Zone -

An HVAC system that can meet different heating and cooling need in different areas simultaneously. Each area (zone) of a building can be regulated by its own thermostat.