Glossary of Ductless Terminology

Ductless Heat Pump Terminology


Every industry seems to have their own jargon and acronyms.  Using this glossary of ductless heat pump terminology will help in your understanding of ‘the language’ and will help you stay on the same page as your ductless contractor.

We know if can feel daunting, so we created The Ductless Directory to guide and educate you through what should be a painless and potentially life-changing process.

Here’s the ductless heat pump terminology cheat sheet on everything you need to know:

AFUE – Annual Fuel Utilization Efficiency. AFUE is a rating that reflects how efficiently a gas furnace converts fuel to energy. An AFUE of 90 means that approximately 90 percent of the fuel is utilized to provide warmth to your home, while the remaining 10 percent escapes as exhaust.

Air Filtration System – A device that removes allergens, pollutants and other undesirable particles from air that is heated or cooled.

Air Handler -The indoor component of your air conditioner or heating system that moves air through your home.

Allergen – A substance that causes an allergic reaction. It includes dust, pollen, pet hair and dander, dust mites, mildew, lint, fungus, most tobacco smoke, cooking grease and bacteria.

BTU – British Thermal Unit. In scientific terms, it represents the amount of energy required to raise one pound of water one degree Fahrenheit. One BTU is the equivalent of the heat given off by a single wooden kitchen match. For your home, it represents the measure of heat given off when fuel is burned for heating, or the measure of heat extracted from your home for cooling.

Capacity – The output or producing capability of a piece of cooling or heating equipment. Cooling and heating capacity are normally referred to in BTUs.

CFM – Cubic Feet per Minute, a standard of airflow measurement. A typical air conditioning system produces 400 CFM per ton of air conditioning.

Compressor – The heart of an air conditioning or heat pump system. It is part of the outdoor unit that pumps refrigerant. The compressor maintains adequate pressure to cause the refrigerant to flow in sufficient quantities in order to meet the cooling requirements of the system and your home.

Cycling – Refers to the process of an HVAC system turning on and off. Some systems require less cycling than others, leading to higher energy efficiency and less wear on the system.

Damper – Found in ductwork, this movable plate opens and closes to control airflow. Dampers are used effectively in zoning to regulate airflow to certain rooms.

Ductless AC (air conditioning) – Refers to the ease of adding AC to your home via a ductless heat pump or ductless mini-split system. The system provides Air Conditioning to your home or business.

Ductwork – Pipes or channels that carry air throughout your home.

Energy Star ® – A program developed by the Environmental Protection Agency (EPA) in order to reduce the nation’s energy consumption. ENERGY STAR® -qualified heating equipment can be up to 15 percent more efficient than standard models. ENERGY STAR® -qualified cooling equipment can be up to 7 percent more efficient than minimum standard equipment.

FAD – Factory Authorized Dealer.  When hiring a ductless contractor make sure that they are an authorized dealer for the brand they are representing.

Furnace – An indoor heating unit that works in conjunction with an air conditioner or heat pump.

Heat Pump – An outdoor unit that warms your home in winter and cools your home in summer.

HEPA Filter – A High-Efficiency Particulate Absorbing filter. A HEPA filter removes particles from the air by trapping them as air flows through.

Home Automation – Anything that gives you remote or automatic control of things around your home, including but not limited to your HVAC, lighting or security system.

HSPF – Heating Seasonal Performance Factor. Refers to the efficiency of the heating mode of heat pumps over an entire heating season: The higher the number, the more efficient the unit.

Humidifier – A device that adds moisture to dry indoor air during wintertime and in hot, dry climates.

Humidity – The amount of moisture in the air. Variable speed systems can reduce this moisture for added comfort.

HVAC – The classic acronym for Heating, Ventilation and Air Conditioning. Today, an HVAC system also includes air cleaning and moisture control.

Hybrid Comfort System – A home comfort system that combines a heat pump with a gas furnace (also available in packaged systems). For areas with colder temperatures, combining electric heating (heat pump) with gas heating (furnace) lets you choose from two fuel sources in order to respond to fluctuations in utility costs.

Inverter Technology- An inverter is an energy saving technology that eliminates wasted operation in air conditioners by efficiently controlling motor speed.  Motor speed in non-inverter type air conditioners remains constant and the temperature is adjusted by turning the motor ON and OFF, which consumes more energy. With Inverter type air conditioners, the temperature is adjusted by changing motor speed without turning the motor ON and OFF. Compared to non-inverter type air conditioners, air conditioners with inverters have less power loss and can save 30% more in energy.

Load Calculation – A detailed analysis of your home’s energy needs conducted by your dealer to help determine which comfort system is best for your home.

NATE – North American Technician Excellence. This is the nationwide certification program for home heating and cooling technicians. It’s the only certification that is recognized by the entire industry.

Outdoor Unit – The outdoor portion of a split system, such as an air conditioner or heat pump. May also be a packaged air-conditioning and/or heating system in which all components are located in one cabinet.

Refrigerant – A substance that produces a cooling effect. It’s used in most air conditioning and cooling systems.

SEER – Seasonal Energy Efficiency Ratio. This is a rating that measures the cooling efficiency of a heat pump or air conditioner. The higher the number, the more efficient the unit.

Split System – Refers to a comfort system consisting of components in two locations. Common examples include an outside unit, such as an air conditioner, and an indoor unit, such as a furnace with a coil. Also referred to as a mini split system or ductless heat pump.

Thermostat – A temperature-control device, typically found on a wall inside the home. It consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system. A programmable thermostat allows you to program different levels of comfort for different times of the day.

Variable-Speed Motor – The fan motor inside higher efficiency indoor and outdoor units is designed to change its speed based on your home’s heating and air conditioning requirements. Working in conjunction with your thermostat, it keeps the appropriate temperature air (e.g., warm air on cold days) circulating throughout your home, reducing temperature variances. The variable-speed motor also increases dehumidification and is quiet because it runs at a lower speed most of the time. Plus, the consistent air circulation eliminates noisy startups and shutdowns.

Zoned Heating And Cooling –  A system that divides a home, office or space into different regions in order to better control the temperature and effectiveness of a heating and cooling system.

Please bookmark this Glossary, so you can return to it whenever you have the need.