By knowing more about your equipment and how it works, you can make more informed and better decisions when it is time to repair, replace, or purchase new equipment.


Heat Pump: A heating and air conditioning piece of equipment used to both HEAT and COOL a building. This really is a “Reverse Acting Air Conditioner”. It is capable of reversing the flow of refrigerant in a cooling system, therefore, extracting heat from outdoors which is then brought to the indoor coil in the AIR HANDLER and distributed to the building through ductwork. Additional ELECTRIC HEAT STRIPS are added to the AIR HANDLER to help heat the building if the outdoor temperature is extremely low.

Split System: The combination of an outdoor unit (air conditioner or heat pump) with an indoor unit (furnace or air handler). Split systems must be matched for optimum efficiency.

Package Unit: A heating and cooling system contained in one outdoor unit. A package unit is typically installed either beside or on top of a home. There are no refrigerant lines to run and no indoor section because it is self-contained unit.

Gas Furnace Heat Exchanger: Located in the furnace, the heat exchanger transfers heat to the surrounding air, which is then pumped throughout your home.  This must be checked over time to ensure there are no cracks, or it will need to be replaced for safety reasons.

Ductless mini-split – What the rest of the world uses for air conditioning. It’s a split system heat pump that’s smaller and (usually) has no ducts. The blower and evaporator coil are in the head, which is mounted on a wall or ceiling in the room you’re trying to cool.

Compressor:  The heart of an air condition or heat pump system.  It is part of the outdoor unit and pumps refrigerant in order to meet the cooling requirements of the system.

Condenser Coil or Outdoor Coil: In an air conditioner, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid. In a heat pump system, it absorbs heat from the outdoors.

Evaporator Coil or Indoor Coil: The other half of your air conditioning system located inside your home in the indoor unit.  This is where the refrigerant evaporates as it absorbs heat from the air that passes over the coil.

Thermostatic Expansion Valve (TXV): Refrigerant control which monitors the flow rate according to the superheat at the evaporator outlet.

Filter Drier: A device that removes moisture, acid and foreign matter from the refrigerant. A new filter drier has to be installed any time the refrigerant circuits are opened.

Capacitor: An electric device consisting of two or more conducting plates separated from one another by an insulating material and used to store an electrical charge. There are RUN capacitors and START capacitors. These parts are replaced every few years due to any electric surges that makes them weak, swollen or not operate at manufacturer specs.

Contactor: An electrical relay which controls the flow of electricity to different components in the system.

Ductwork: Pipes or channels that carry air throughout your home. In a home comfort system, ductwork is critical to performance in fact, it’s as critical as the equipment.  The equipment can only function as well as the ductwork that delivers it to your home.

Damper: Found in ductwork, this movable plate opens and closes to control airflow.  Dampers can be used to balance airflow in a duct system. They are also used in zoning to regulate airflow to certain rooms.  Dampers can be manual or motorized.

Zoning: A method of dividing a home into different comfort zones so each zone can be independently controlled depending on use and need.

Thermostat: A thermostat consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system.

SEER: Seasonal Energy Efficiency Ratio. A Measure of cooling efficiency for air conditioners and heat pumps. The higher the seer, the more energy efficient the unit. The government’s minimum SEER rating is 14, as of Jan. 2015. (It’s similar to comparing miles per gallon in automobiles).

HSPF: Heating Seasonal Performance Factor.  This rating is used in measuring the heat efficiency of a heat pump. The higher the number, the more efficient the unit.

Ton: A unit of measurement used for determining cooling capacity.  One ton is the equivalent of 12,000 BTUs per hour.

Capacity:  The output or producing ability of a piece of cooling or heating equipment. Cooling and heating capacities are referred to on BTUs.

CFM: Cubic Feet Per Minute. A standard measurement of airflow. A typical system requires 400 CFM per ton of air conditioning.

BTU: British Thermal Unit.  This is the amount of heat it takes to raise one pound of water one degree Fahrenheit.  For your home, it represents the measure of heat given off when fuel is burned for heating or measure of heat extracted from your home for cooling.

AFUE: Annual Fuel Utilization Efficiency. A measure of a gas furnace’s efficiency in converting fuel to energy the higher the rating, the more efficient the unit. For example: A rating of 90 means that approximately 90% of the fuel is used to provide warmth to your home, while the remaining 10% escapes as exhaust.

Refrigerant: A chemical that produces a refrigerating effect while expanding and vaporizing. Most residential air conditioning systems contain Puron R-410A refrigerant.  R-410A is regulated by international controls under the Montreal Protocol and in the US by the Environmental Protection Agency.  It is the environmentally friendly refrigerant that came out after R-22 (which will not be produced after 2020).