Here are a few of the more common terms you will hear when discussing your homes heating and cooling systems.

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Air Conditioner (A/C)
An air conditioner is an outdoor unit that cools air for your home and sends it to the indoor unit such as an air handler or furnace to circulate through the house for maximum comfort. This equipment operates off of electricity. You may hear this equipment referred to as the compressor or condensor. Air conditioners also require refridgerant to operate.

Air handlers
The air handler is the indoor unit that runs off of electricity that circulates warm air in your home in the winter and cool air in your home in the summer. The air handler works with your outdoor equipment, so either your air conditioner or your heat pump.

Annual Fuel Utilization Efficiency (AFUE)
The AFUE is the most widely used measure of a furnace’s heating efficiency. It measures the amount of heat actually delivered to your house compared to the amount of fuel that you must supply to the furnace. Thus, a furnace that has an 80% AFUE rating converts 80% of the fuel that you supply to heat — the other 20% is lost out of the chimney.

Note that the AFUE refers only to the unit’s fuel efficiency, not its electricity usage.

The US Department of Energy (DOE) determined that all furnaces sold in the US must have a minimum AFUE of 78%, beginning January 1, 1992. Mobile home furnaces are required to have a minimum AFUE of 75%.

The DOE’s technical definition of AFUE is as follows:

The measure of seasonal or annual efficiency of a furnace or boiler. It takes into account the cyclic on/off operation and associated energy losses of the heating unit as it responds to changes in the load, which in turn is affected by changes in weather and occupant controls.

A boiler is an indoor unit that heats and circulates water throughout your home. A homeowner can opt to contract for one that operates off of electricity, gas or oil.


The main component in the outdoor unit that produces the cooling comfort inside your home.

Condenser Coil

This is located in the outdoor unit and dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid.

A device that removes humidity, or moisture, from the air.

Heat Pump
A heat pump is an outdoor unit that runs off electricity and it heats your home in the winter by drawing air from the outdoors and cools your home in the summer by using your indoor air.

An indoor air quality device that introduces moisture to heated air as it passes from the furnace into the ductwork for distribution throughout the home.

Electronic air cleaner
A filter that uses electricity to create a slight magnetic charge to help collect smaller particles. The EAC then draws tiny particles that are magnetized, such as viruses and bacteria, to a collector plate to remove them from the indoor air in your home.

The furnace is an indoor unit that is usually located in an attic, equipment closet or a crawl space. Homeowners can opt to contract for a furnace that powers off of electricity, natural or propane gas. Either are designed to work with an outdoor unit such as an air conditioner or heat pump. The furnace circulates warm air in your home in the winter and cool air from the air conditioner in the summer. You may hear this equipment also referred to as a heat exchanger.

Package Unit
A package unit is an all in one outdoor unit that provides central air for winter and summer months. In a packaged system, all equipment is built into an outdoor unit, usually on a concrete slab or other platform. The “package” that gives it its name provides central air conditioning during the summer and heat in colder months.

Models available use:

  • Electricity for resistance heating and cooling
  • Gas for heating and electricity for cooling
  • Heat pump models using electricity

The efficiency of packaged systems are rated using SEER (for cooling efficiency), AFUE% (for gas heating efficiency) and HSPF (for heat pump efficiency). Ductwork is required to transfer the heated or cooled air throughout the home.

SEER (Seasonal Energy Efficiency Ratio)

The efficiency of air conditioners are measured and referred to as SEER ratings.  The Department of Energy regulates the minimum standard rating for equipment manufacturers.  The lowest produced SEER is 14 in the current market.  The higher the efficiency rating, the less energy the equipment uses which in turn lowers your energy costs.


A wall mounted device that connects to and operates the heating and cooling equipment that regulates the indoor temperature.

UV Treatment

A comfort system enhancement improves indoor air quality and eliminates allergens, mold and bacteria that grow in the moist environment of your indoor coil.