Technical Definitions

Questioning “what is a chimney liner” or “what is a condensate pump”? Our website is dedicated to helping you understand and learn plumbing terms and definitions. Read below to learn about AFUE, chimney liners, compressors, evaporator coils, and more.

Glossary of Terms:

80% AFUE: This type of furnace is 80% efficient. Stated another way, approximately 80% of the gas burned goes to heat the house. The remaining 20% of the heat is expelled up the chimney.

90% AFUE: This type of furnace is 98% efficient. For every dollar of gas the furnace consumes, 90 to 98 cents goes into heating the house, and the remaining few pennies are wasted. This type of furnace is also called a condensing furnace because when gas is burned, it produces water vapor condensed inside the furnace.

AFUE:  Annual Fuel Utilization Efficiency. This measures the average efficiency of a gas-burning appliance over a year, in this case, a furnace or boiler.

Adaptive Heat Stage Control:  A control that enables the furnace to modulate the gas burner and blower speed to provide just the right amount of heat the house needs to maintain temperature without the temperature swings associated with single-stage equipment.

Air Filter:  Standard:  1″ mesh type disposal filter provides the lowest level of filtration. This type of filter must be changed once a month to prevent equipment breakdown. See “Media Air Filter,” “HEPA Filter,” and “Infinity Air Purifier” below.

Burner Stages:  A multiple-stage furnace burner can operate at partial or full heating capacity based on how much heat is required to maintain the desired temperature within the home. These systems are designed to increase comfort and reduce operating costs in all weather conditions.

Chimney Liner:  A flexible metal tube is installed in the masonry chimney to reduce the internal size of the chimney. A liner is necessary to prevent condensation due to the installation of smaller, more efficient heating equipment. If condensation were allowed, it would eventually damage the chimney.

Compressor:  The compressor is the electro-mechanical heart of the cooling system. It is a pump that moves refrigerant under pressure from the outside condensing unit to the indoor evaporator coil to extract heat from inside the home and expel that heat outside the home, thereby cooling the house.

Condensate Pump:  A receiver and pump that allows condensate from the air conditioner, 90% efficient furnace, or water from a humidifier to be pumped to a drain. A condensate pump is necessary if the furnace is not near a floor drain.

Condensing Unit:  The heart of the cooling system, which sits outside the house. The condensing unit contains a compressor and a condensing heat exchanger. The compressor circulates the refrigerant through the system to draw heat from the home’s inside and expels that heat to the outside via the condensing heat exchanger.

Condenser Pad:  This pad sits underneath, supports the condensing unit, and keeps the unit level. If an air conditioning condenser is not level, it can cause damage requiring expensive repairs or premature replacement.

Drier:  A filter installed into the air conditioning system that protects the system.

Electric Disconnect:  An exterior electric switch allowing a service technician to disconnect power to the condenser for easy maintenance.

Electronic Air Filter:  Uses metal mesh filters and electrostatic cells to remove minute particles from the return air. Mesh pre-filters must be cleaned monthly, and cells washed every 90 days. It provides a high filtration level with the least airflow resistance but consumes electricity to do so.

Evaporator Coil:  The other half of the air conditioning system. This heat exchanger sits downstream of the furnace. The refrigerant flows through the evaporator to absorb heat from the house. The evaporator must be matched to the condensing unit to obtain the stated efficiency.

Extended Warranty:  Increases the manufacturer’s equipment and contractor’s labor warranty for ten years. Please note that the customer must be able to prove that proper annual equipment maintenance has been performed for an extended warranty to remain in effect. 

Heat Exchanger:  Natural gas burns inside the heat exchanger and transfers that heat to the air in the home or water for the radiators. The combustion byproducts are then carried out of the heat exchanger through the flue system to the chimney or directly outside the house.

Heat Pump:  This is a component of a heating and cooling system.  A heat pump looks just like your outside air conditioning condensing unit but in addition to providing cooling in the summer time, it can also provide heat in the winter.  When installing this type of system we program the current cost of electricity and gas into the thermostat which will then determine if it is more cost efficient to heat with the gas furnace or with the heat pump.

HEPA Filter:  This system filters a percentage of the air returning to the furnace, providing the highest level of particle filtration.

Home Care Club:  A low-cost preventative maintenance agreement for your heating and cooling system. The equipment manufacturer and the extended warranty company require that new equipment be adequately maintained for the warranties to remain in effect. Even though the equipment is new, one year of usage will make a new unit just as dirty as one year on an old unit. For this reason, we recommend our customers take advantage of our Home Care Club pricing on preventative maintenance equipment tune-ups. Click here to see all the benefits of our Home Care Club.

HRV (Heat Recovery Ventilator):  Exchanges stale building air with fresh outdoor air. Fresh air is filtered and heated (or cooled) with a recovery system allowing more energy-efficient operation.

HSPF2: Heating Seasonal Performance Ratio 2 is used to measure a heat pump’s heating efficiency. The Department of Energy has established 7.5 HSPF2 as the minimum efficiency for residential, air-source, split-system heat pumps. While some of the highest-performing air-source heat pumps are rated at 10.5 HSPF2, anything rated at 9 HSPF2 or greater is considered to be a high-efficiency model.

Humidifier:  A device that maintains the proper humidity level in the home. The humidifier attached to the furnace ductwork adds moisture to the air. Acceptable humidity levels, typically between 20% to 50% relative humidity, are necessary to make your home comfortable during the heating season. Proper humidity reduces dry throat and skin, reduces static shocks, keeps furniture and your home from cracking, and increases equipment energy efficiency. It’s become well known that a home with proper humidity feels warmer than a dry home, even at lower temperature settings.

Humidity Control:  The furnace and air conditioner work together to reduce the humidity levels in the home without providing significant cooling. This mode of operation can increase comfort on humid days with mild temperatures.

HVAC:  Stands for Heating, Ventilation, and Air Conditioning. It refers to the entire system that heats and cools your house, including the furnace, air conditioner, air cleaner, and humidifier, and the ductwork that conveys the conditioned air throughout the house.

Infinity Air Purifier:  The Infinity Air Purifier is Carrier’s premier air purification solution. It’s ideal for homeowners with allergy concerns, those susceptible to airborne germs, such as infants and the elderly, and those sensitive to the effects of mold, pollen, pets, and more.

  • The Infinity Air Purifier offers extremely high air filtration efficiency and patented germicidal technology so effective it even captures and kills airborne pathogens such as bacteria, viruses, and mold.
  • Treats the air throughout the entire home.
  • Technology is trusted to protect secure government facilities and hospital room patients.
  • No cleaning is required; remove and replace the media cartridge to maintain peak performance.
  • Replacement cartridges (replaced annually) currently cost $95.00

Infinity Control:  The infinity system combines Carrier’s best products into the world’s most complete residential comfort system. This system maximizes comfort, energy savings, and peace of mind by combining Carrier’s variable speed furnaces, a Carrier air-conditioning unit, and the Infinity Control. At the heart of the system is the Infinity Control, which features the industry’s largest backlit liquid crystal display, making it easier to read, even at night. Intuitive prompts let you program everything from humidity levels to fan speeds, giving you the ultimate control over your home comfort. Standard features include:

  • 4-wire installation means less expense associated with pulling new thermostat wire.
  • Intuitive on-screen prompts for ease of installation and service.
  • Ideal humidity settings to automatically control humidity levels.
  • Complete integration of the temperature, humidity, and ventilation in every season.
  • 7-day programmability with 2 or 4 periods per day.
  • Easy timed programming override schedule.
  • It simplified my vacation schedule.
  • Day-at-a-glance programming for simplified ease of use.
  • Programmable fan by period.
  • Automatically detects and notifies you of a dirty air filter.
  • Indoor Air Quality pop-up reminders.
  • General maintenance reminder messaging.
  • 5-year warranty

Line-set:  Tubing that connects the outdoor condensing unit to the indoor evaporator coil. The line set allows the refrigerant to circulate through the system.

Load Calculation:  This is necessary to ensure that the heating and cooling equipment we will install in your house is appropriately sized for the home. This job is performed by measuring the entire house, or at least the zone controlled by the HVAC system being replaced and applying a bit of science related to the heat transfer properties of the various building materials used in the construction of your home coupled with our average weather data. Bigger is not better as it relates to heating and cooling equipment. An oversized unit will short cycle, significantly reducing efficiency, and run hotter than it should, shortening its life. An oversized air conditioner will leave the occupants with a cold and clammy feeling or not work.

Media Air Filter:  A 4″ to 5″ thick filter to catch smaller particles. Requires replacement once every six months.

Modulating:  This type of furnace can regulate the amount of gas to meet the heat required to keep the home comfortable. This allows for the most efficient furnace operation during all weather conditions.

Return Air Box:  A sheet metal box that sits under the furnace, which helps increase airflow. Increased airflow improves the overall efficiency of the heating and cooling system.

Return Drop:    Sheet metal duct that conveys the return air to the furnace. The return drop sometimes includes a 1″ thick filter rack.

Reversing Valve:    This is a component of a heat pump (see definition above).  The reversing valve allows the outside condensing unit to let the refrigerant in its system to run in one direction for cooling or in the reverse direction for heating.

RGF Guardian Air Purifier:  Stated this system disinfects your home like an invisible spray of Lysol. To be more exact, this system uses a combination UVC lamp with a photohydroionization (PHI) cell. This unit creates 0.01 to 0.02 parts per million (as diluted in the air within the home) of hydroperoxide and hydroxide ions, which are friendly oxidizers. By friendly, the oxidizers will revert back to oxygen and hydrogen after the destruction of the pollutant. The system will reduce or eliminate odors, air pollutants, VOCs (chemical odors), smoke, mold, and bacteria and viruses, including Swine Flu, Candida, Bird Flu, Norwalk, Listeria, MRSA, E.coli, Bacillus sp, and Strep with a 99+% kill rate on surfaces and airborne. Kill rates confirmed by independent testing laboratories. 

SEER:  Stands for Seasonal Energy Efficiency Ratio, which is a measure of the overall efficiency of the air conditioning condensing unit. For example, a 12 SEER unit will use ½ the electricity as a 6 SEER unit under the same operating conditions. For comparison, a 16 SEER unit will use about 23% less electricity than a 13 SEER unit under the same operating conditions.

SEER2:  This is the new and updated SEER standard.  This updated testing standard that more accurately reflects the air flow through ductwork in the average house.

Single Stage Burner:  The furnace burner operates at one continuous rate from the time the burner starts until the thermostat is satisfied and the furnace burner shuts off.

Thermostat:  The thermostat controls the temperature in the home by turning the furnace and air conditioner on and off. Installing an electronic programmable thermostat is the simplest way to cut your heating and cooling bills. These thermostats provide pinpoint accuracy and control for improved efficiency over old-fashioned mechanical thermostats. Programmable thermostats will automatically adjust your home’s temperature on the schedule you decide and are far easier to program than earlier models. Internet-based thermostats can be programmed and monitored via smartphones, tablets, or computers. These thermostats can alert you if the temperature in the home becomes hotter or colder than the emergency threshold set by the homeowner.

Two-Pipe Vent System:  Our venting will consist of two appropriately sized PVC pipes running from the furnace to the outside of your home. One line will bring combustion air to the furnace, and the other will exhaust the combustion products. Many competitors will only install one pipe for exhaust, drawing combustion air from your living space and adversely affecting your home’s air quality. 

Two-Stage Burner:  The furnace burner operates at 70% of capacity on startup and only increases to its total capacity when needed. This system is designed to increase comfort and reduce operating costs in all weather conditions.

UV Filter:  Installed in the furnace ductwork, these units reduce odors and kill bacteria, mold, and mildew. Requires bulb replacement once per year.

Variable Speed Blower:  The furnace blower motor can run at the speed necessary to provide the proper heat to heat the house adequately. This allows the system to maximize energy savings and comfort. Manufacturers show an average savings of $300.00 annually with this blower motor.

Zone Control System:  This system is installed to separate the structure into heating and cooling zones. The environment of each zone is controlled by a separate thermostat (or zone controller). Typically, the number of possible zones depends upon the ductwork layout within the structure.a