As with any highly skilled trade, heating, ventilation and air-conditioning (HVAC) contractors and technicians have their own industry language. They use a variety of concepts and terms that most of us do not deal with on a day-to-day basis. A good HVAC contractor will take the time to explain everything to you when installing a new system or performing maintenance, but it doesn't hurt to have some basic knowledge so that you can ask intelligent questions and ensure the efficiency of your equipment. Here's a list of some of the terms you may confront.
AFUE—Stands for “annual fuel utilization efficiency.” It’s a rating system of how well a boiler or furnace converts fuel into heat. The higher the AFUE, the more efficient the boiler or furnace.
ACH—Stands for “air changes per hour.” That’s the number of times the air in a given space, such as a house, is completely changed thanks to mechanical or natural ventilation.
Air filters—Placed on the return side of furnaces to remove dirt, dust and other debris from reaching the working parts of the furnace.
Air handler—The part of a heating and/or cooling system that is responsible for the air flow through the ductwork.
Boiler—A unit that converts a fuel, such as natural gas, into steam or hot water for home heating.
BTU—An abbreviation of British Thermal Units, a measurement of heating or cooling capacity. You will see it as part of equipment descriptions. It is equal to the amount of heat is required to raise one pound of water one degree Fahrenheit.
Coil—Part of the heat transfer system. There are two types of coils. In an air-conditioner or heat pump, an evaporator coil removes heat from the indoor air; the condenser coil removes heat from the system and is located outdoors. Because heat pumps provide both heating and cooling, the role of these coils can change.
Compressor—Located outdoors, the compressor converts a low-temperature, low-pressure refrigerant into a high-temperature, high-pressure refrigerant. This conversion aids the condenser in emitting heat from the air-conditioning system.
Condenser—Part of a central air-conditioning system or heat pump that ejects heat from the system. The condenser is the outdoor part of a central air-conditioning system.
Dampers—Located inside the ductwork, these plates direct air flow.
Ducts—A delivery system that carries heated or cooled air throughout the home.
Energy audit—A survey of the "energy package" of a home. The audit will include an examination of heating and cooling equipment, as well as types of windows, insulation levels, air infiltration, and ventilation.
Energy Star—A joint program of the Department of Energy and the Environmental Protection Agency that rates a variety of appliances, including heating and cooling equipment. Energy Star products are more energy-efficient than typical models. Manufacturers that meet the requirements can place the Energy Star logo on their qualifying products.
Evaporator—More in depth explanation at “coil”.
Furnace—A heating unit that coverts a fuel, such as natural gas, into heated air.
Heat exchanger—A device that transfers heat from one medium to another. In a furnace, burners heat the heat exchanger, which is a series of tubes and coils. A fan blows air over the hot coils. The coils heat the air, which then flows through the home's ductwork.
Heat pump—An appliance that can switch between heating and cooling modes.
HSPF—Stands for “heating season performance factor.” It is used to describe the heating efficiency of heat pumps. SEER is a similar term that’s used to measure cooling efficiency (see below).
Humidifier—A device that adds moisture to the air as it travels from a furnace through the ductwork.
IAQ—Stands for “indoor air quality.” Tightly sealed houses need proper ventilation to avoid poor air quality.
Load calculation—A way to determine the amount of heating and cooling capacity a home needs.
Programmable thermostat—A control device that can alter the temperature settings of the heating and cooling system depending on the time of day.
Refrigerant—A heat-transfer fluid that circulates between the evaporator coil and the condenser in an air-conditioning system and heat pump. The compressor increases the temperature and pressure of the refrigerant before it reaches the condenser.
Return side—The part of an HVAC system that returns air from the home to the furnace or air conditioner. The return side should be balanced with the supply side.
SEER—Stands for “seasonal energy-efficiency ratio.” This is an energy-efficiency rating for air-conditioners. The higher the rating, the more efficient the product.
Single-package system—A unit that contains both heating and cooling components.
Split system—An air-conditioning system that contains both indoor and outdoor components.
Supply side—The part of an HVAC system that supplies heated or cooled air to the home. The supply side should be balanced with the return side.
Ton—Used to describe a cooling system's size. One ton equals 12,000 BTU.
Zoned system—A heating and cooling system that is divided into certain sections. For example, one zone may include the first floor of a house; another zone may cover the second floor. Each section is controlled by its own thermostat.
Once you understand the basic concepts and terms of heating and cooling, you’ll be able to communicate better with your contractor. You will also be more skilled at determining which systems are more energy-efficient and keeping up with the status of your current equipment.
Written by Fran Donegan
Originally posted on proudgreenhome.com