AIR HANDLING UNIT

The section of an air conditioning and/or heating system usually located inside the house that consists of a heating component, a blower, and often a cooling coil all in a single cabinet.  When the heating element consists of gas burners, this referred to a furnace.

AIR BALANCING

Adjusting the conditioned airflow to provide even temperatures throughout the building. This is achieved by adjusting manual dampers located inside the ductwork, near the air handler.

BTU

A British Thermal Unit is used to measure heating and air conditioning capacity.  In layman’s terms, a BTU is the approximate amount of heat put out by a wood match.  The average air conditioning unit removes 36,000 BTUs of heat per hour, or 36,000 matches’ worth, whereas a typical gas furnace adds 60,000 BTUs of heat to the air.

COIL

A component used for heating or cooling that is made up of rows of copper or aluminum tubing, connected to each other with plating.  A coil is used to transfer heat out of or into a building.  A car radiator functions in much the same way.  On split systems, there are two coils, an evaporator/cooling coil on the inside which removes heat from the air, and a condensing coil on the outside, which dissipates that heat into the outside air.

CONDENSER

The outdoor cabinet on a split heat pump or air conditioning system.  This cabinet houses a compressor, a coil, a fan, and other smaller components.  In the summer, this unit dissipates the heat removed from the interior of the house into the outside air.  If it is a heat pump condenser, it can run in reverse, removing heat from the outside air, sending it inside.

DOE/EPA

The U.S. Department of Energy and the Environmental Protection Agency are the federal agencies that set industry efficiency standards, and require consumer efficiency ratings, such as the Energy Star standards.

DUCTWORK

Conduits used to carry conditioned air.  They can be round or rectangular, sheet metal or fiberglass or insulated flexible plastic tubes.  In air conditioning systems they recirculate conditioned air inside a building.

EER

Energy Efficiency Rating which measures the steady state efficiency of a cooling system at an outside temperature of 95 degrees.  This is calculated by dividing the capacity of the unit in BTUs by the electrical power in watts.  The higher the rating the less energy the appliance requires.  Ratings range from 8 to 14.

ENERGY STAR®

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

FURNACE

A combination gas fired heating unit and blower that is designed to deliver heater or cooled air into the home.

HEAT EXCHANGER

1.  The part of a furnace that transfers heat from burning fuel to the air used to heat your home.
2.  The part of an air handler that transfers heat from a hot water source into the air, i.e. hydronic heating.
3.  An HVAC component, such as a condenser or evaporator coil, in which heat is added or removed in order to warm or cool your home.

HEAT PUMP

An air conditioning system that not only extracts heat form the inside a building and dissipates it to the outside, but also can run in reverse to extract the heat from the outdoor air and dissipate to the inside.

HSPF

Heating Seasonal Performance Factor, which measures the heating efficiency of a heat pump system during the entire heating season.  The higher the rating the less energy the appliance requires.  Ratings range from 7.7 to 10.

HVAC

Heating, ventilating, and air conditioning.  This acronym is usually interchangeable with ‘heating and cooling system.’

HVAC LOAD CALCULATION

A mathematical determination of how much cooling and heating (BTUs) an HVAC system must deliver for occupant comfort.  It is based on a variety of factors: square footage, building orientation, number of occupants, size and placement of rooms, number and size of windows and doors, amount of insulation, number of floors, and climate.  It is also dictated by an occupant’s comfort goals.

INFILTRATION

Air that enters your home through holes, gaps, and cracks, (e.g., plumbing or electrical holes, doors, and windows).  The worst offender is recessed lights.  The main driver is the HVAC distribution system.

R-22 REFRIGERANT

The former refrigerant of choice in cooling systems that can no longer be used in the manufacturing of air conditioning systems since January of 2010. The EPA has mandated that the quantity of R-22 manufactured will decrease yearly and be phased out entirely by 2020.  It is most commonly referred to by its trademarked name, Freon.

R-410A REFRIGERANT

This non-chlorine based refrigerant that has replaced R-22 in air conditioning systems.

REFRIGERANT CHARGE

Checked using special gauges connected to an air conditioning or heat pump condenser which measures refrigerant pressure inside the system.  This information is used to determine equipment functionality relative to manufacturer specifications.  If these specifications are not met, it is then used as a diagnostic tool to identify the cause of the discrepancy.

RETURN AIR

It is the ‘return’ part of the conditioned air circulating system where the air enters openings that are connected to the air handler or furnace so it can be conditioned and recirculated throughout the house.  Their size, configuration, and location must be properly designed to ensure sufficient air flow and comfort.

SEER

Seasonal Energy Efficiency Ratio, which measures the energy efficiency of an air conditioning system during the entire cooling season.  The higher the rating the less energy the appliance requires.  Ratings range from 13 to 26.

SPLIT SYSTEM

A split system is by far the most common configuration used in homes. It is a two-component system.  The heating, blower, and cooling coil component of the unit are installed inside, and the condensing component is installed outside.  Refrigerant lines and wiring connect them together.

SUPPLY AIR

It is the ‘supply’ part of the conditioned air circulating system where the air exits openings (vent registers) that are connected to the air handler or furnace delivering conditioned air throughout the building.  Their size, configuration, and location must be properly designed to ensure sufficient air flow and comfort.

ZONING SYSTEMS

A zoning system is installed on a central air conditioning system in order to better control the temperatures of up to four distinct sections (zones) of a building.  This is done by installing motorized dampers to control the amount of air flowing to each zone.  Each zone has its own thermostat, which are wired to an electronic control board along with the dampers.  When any zones’ thermostats call for conditioned air, those dampers will open and the other dampers will close, forcing the conditioned air to the zones that need it.