Glossary of Terms

Annual Fuel Utilization Efficiency (AFUE):
A rating that denotes the efficiency of gas heating equipment. It is the amount of heating your equipment delivers for every dollar spent on fuel. A higher rating indicates more efficient equipment. This rating is calculated in accordance with the Department of Energy test procedures.
Air Flow:
The distribution or movement of air.
Air Handler:
The portion of the central air conditioning or heat pump system that moves heated or cooled air throughout a home’s ductwork. In some systems a furnace handles this function.
BTU (British Thermal Unit):
The standard of measurement used for measuring the amount of heat required to raise the temperature of one pound of water by one degree (Fahrenheit). BTUH - The number of BTUs in an hour.
Carbon Monoxide:
Carbon Monoxide (CO) is a colorless, odorless gas produced by burning any fuel. CO is poisonous and symptoms of CO poisoning are similar to those of the flu: headaches, fatigue, shortness of breath, nausea and dizziness. The Consumer Product Safety Commission (CPSC) recommends a yearly, professional inspection.
CFM (Cubic Feet per Minute):
The abbreviation for cubic feet per minute, commonly used to measure the rate of air flow in an air conditioning system.
Compressor:
The pump that moves the refrigerant from the indoor evaporator to the outdoor condenser and back to the evaporator again. The compressor is often called “the heart of the system” because it circulates the refrigerant through the loop.
Damper:
Found in ductwork, this movable plate opens and closes to control airflow. Dampers are used effectively in zoning to regulate airflow to certain rooms.
Ductwork:
Pipes or channels that carry air throughout a building.
Energy Star®:
An EPA (Environmental Protection Agency) designation attached to HVAC products that meet or exceed EPA energy guidelines for high—efficiency systems.
Evaporator Coil:
Part of split system air conditioner or heat pump indoors. The evaporator coil cools and dehumidifies the air by converting liquid refrigerant into a gas, which absorbs the heat from the air. The warmed refrigerant is then carried through a tube to the outdoor unit.
Heat Exchanger:
Located in the furnace, the heat exchanger transfers heat to the surrounding air, which is then pumped throughout your home.
Heat Pump:
A heat pump is a HVAC unit that heats or cools by moving heat. During the winter, a heat pump draws heat from outdoor air and circulates it through your home’s ductwork. In the summer, it reverses the process and removes heat from inside your home and releases it outdoors.
HSPF:
The Heating Seasonal Performance Factor is a measure of the heating efficiency of a heat pump. The higher the HSPF number, the more efficiently the heat pump heats your home.
HVAC:
Term used for Heating, Ventilation, and Air Conditioning.
MERV rating:
Minimum Efficiency Reporting Value. MERV ratings are used to rate the ability of an air conditioning filter to remove dust from the air as it passes through the filter. MERV is a standard used to measure the overall efficiency of a filter. Higher MERV ratings mean fewer dust particles and other airborne contaminants pass through the filter.
Package Unit:
A self-contained heating and/or air conditioning system.
R 410A/Puron©:
Puron© refrigerant is an environmentally sound refrigerant designed not to harm the earth’s ozone layer. Federal law requires that all manufacturers phase out ozone depleting refrigerants in the next few years. Puron© is approved by the US Environmental Protection Agency as a replacement for Freon R22.
Refrigerant Lines:
Set of two copper lines connecting the outdoor unit and the indoor unit.
SEER:
The Seasonal Energy Efficiency Ratio is a measure of the cooling efficiency of your air conditioner or heat pump. The higher the SEER number, the more efficient the system is at converting electricity into cooling power and the more money you can save.
Split System:
Refers to an air conditioner or heat pump that has components in two locations. Usually, one part of the system is located inside (evaporator coil) and the other is located outside (condenser coil).
Thermidistat:
The Thermidistat Control monitors temperatures both inside and outside, as well as indoor humidity and adjusts system operation to maintain the temperature and humidity levels set by the Homeowner.
Ton:
A unit of measurement for cooling capacity. One ton = 12,000 BTU’s per hour.
Upflow:
A type of furnace that draws cool air from the bottom and blows the warmed air out the top into the ductwork. This type of furnace is usually installed in a basement or an out-of-the-way closet.
Variable Speed:
A motor that automatically adjusts the flow of warm or cool air for ultimate comfort.