Common HVAC Terms You Should Know

Familiarize yourself with common HVAC terms. Trust Sandium for expert HVAC technicians and comprehensive knowledge of air conditioning systems. Contact for your queries!

Updated on Oct 22, 2023
5 min read
Common HVAC Terms You Should Know

There is a lot of technical jargon used in the heating, ventilation, and air conditioning industry. This handy guide will help you understand your equipment better in your Bay Area home or business. These terms often come up in conversations with HVAC technicians or written on the manufacturer’s website and written estimates.


HVAC stands for heating, ventilation and air conditioning and is one of the most common terms used.

Annual Fuel Efficiency Ratio

Annual Fuel Efficiency Ratio or AFUE measures the heating system’s efficiency. It is applicable to boilers and furnaces. AFUE measures the amount of fuel used by a boiler or furnace to heat a given space. It also indicates the amount of fuel lost to exhaust. AFUE rating reduces with equipment age. You should consider investing in a new unit if the AFUE is lower than 80%.


This piece of equipment facilitates heat transfer and can be found in ducts and air handling units. Coils are present in the outdoor unit of an air conditioner or heat pump as well.


Air ducts or ductwork are special pipes or channels for supply, return, and exhaust of air within a home. It can be made of different materials, such as galvanized steel, fiberglass plastic, aluminum, and polyurethane.


This piece of equipment is helpful in lowering the humidity levels of indoor air. It cools the air to a temperature point where water vapor becomes liquid. The liquid is then collected in a drain pan or reservoir.

Heat Pump

This piece of equipment has dual temperature control functions. It serves a primary purpose of moving heat energy in opposite directions. The equipment absorbs heat from one space to another with the help of compressor and a chemical refrigerant.


This is a chemical that runs within the coils of your HVAC unit. It creates a cooling effect. R410-A is a popular chemical refrigerant used in air conditioners, freezers, refrigerators, and heat pumps.

Seasonal Energy Efficiency Ratio

SEER or seasonal energy efficiency ratio is used for measuring the efficiency of an air conditioner or a heat pump. SEER measures the total cooling output of a unit during the cooling season by dividing it with the total electricity consumed during the same period. SEER rating is a great way of determining the operating cost of an air conditioner or a heat pump. Higher SEER means the system will use less electricity to cool your home.

Split System

Split or mini-split units can cool different parts of your home at different temperatures. These units don’t use ductwork to distribute cooled or warmed air. Instead, small air handlers are mounted on the ceiling or wall of each zone for complete control over the temperature. There is an individual thermostat in each zone. A major benefit of these systems is the energy you conserve by not having to cool or warm the entire house.

Variable Air Volume

Rate of air flowing through the compressor can vary in these systems. The result is conserved energy by slowing the fall speed. Larger temperature adjustments can be made by operating the compressor and fan at full capacity. By operating at the lowest air capacity, these systems reduce your carbon footprint and save money. 

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