Browse 30 essential hvac contractor terms and definitions used by professionals in Lewisville.
Term Index
Open any term below for a dedicated definition page.
Air Handler is the indoor component of a heating, ventilation, And air conditioning (HVAC) system that circulates conditioned air throughout a building. Air Handlers contain a blower, heating or cooling elements, filter racks, And dampers, working together to regulate temperature, humidity, And air quality in residential and commercial spaces.
Annual Fuel Utilization Efficiency is a standardized measure of how efficiently a gas or oil furnace converts fuel into usable heat over an entire heating season. Expressed as a percentage, it accounts for cycling losses, standby losses, And combustion efficiency, providing a realistic estimate of a furnace’s performance in real-world conditions.
British Thermal Unit is a standard unit of heat energy used in heating, cooling, And power systems. One British Thermal Unit represents the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit at sea level. HVAC systems use British Thermal Units to measure heating or cooling capacity, helping determine the right equipment size for homes and buildings.
Carbon Monoxide Detector is carbon Monoxide Detectors are small, battery-powered or hardwired devices that continuously monitor indoor air for carbon monoxide, a colorless, odorless gas produced by incomplete combustion of fuels like natural gas, propane, oil, wood, Or gasoline. When dangerous levels are detected, the device sounds a loud alarm to warn occupants and prompt evacuation or ventilation.
CFM is the standard unit used to measure how much air moves through a space each minute. CFM stands for cubic feet per minute, showing the volume of air a fan, vent, Or HVAC system can push or pull. Higher CFM means more airflow, which affects heating, cooling, And indoor air quality in homes and buildings.
Compressor is the mechanical heart of an air-conditioning or heat-pump system. Compressor squeezes low-pressure refrigerant vapor into high-pressure, high-temperature gas so it can release heat outdoors and circulate cooled refrigerant back inside the home. Without compressor, no cooling or heating cycle can occur.
Condenser Coil is a heat-exchange component in an air conditioning or heat pump system that releases heat absorbed from indoor air to the outdoor environment. Condenser Coils are typically made of copper, aluminum, Or coated steel tubing and are located in the outdoor unit, where a fan blows air across the coil to cool and condense hot refrigerant gas into a liquid.
Cubic Feet per Minute is a measurement of how much air moves through a space in one minute. It tells how many cubic feet of air pass by a fixed point each minute, helping determine if heating, cooling, Or ventilation systems can handle a room’s size. Proper Cubic Feet per Minute keeps indoor air fresh and comfortable.
Ductwork is a network of tubes, typically made of sheet metal, fiberglass, Or flexible plastic, installed in homes and buildings to distribute heated or cooled air from HVAC systems. Ductwork carries air from furnaces, air conditioners, Or heat pumps to rooms and returns stale air back to the system for reconditioning, ensuring consistent indoor comfort and air quality.
ENERGY STAR is a voluntary U.S. Government-backed program created by the Environmental Protection Agency (EPA) to help consumers and businesses save money and reduce pollution by identifying energy-efficient products and buildings. ENERGY STAR products meet strict efficiency guidelines set by the EPA, often exceeding federal standards without sacrificing performance or features.
Evaporator Coil is a key component in air conditioning and refrigeration systems that absorbs heat from indoor air. Located inside the air handler or furnace, it contains cold refrigerant that evaporates as warm air passes over it, cooling and dehumidifying the air before circulating it back into the home or building.
Heat Exchanger is a critical component in HVAC systems that transfers heat from one medium to another without mixing them. In furnaces, it moves heat from combustion gases to the air circulated through ducts. In air conditioners, it removes heat from indoor air and releases it outside. Proper operation ensures efficiency, safety, And comfort in heating and cooling systems.
Humidifier is a device that adds moisture to dry indoor air to maintain a comfortable and healthy humidity level, usually between 30% and 50%. Humidifiers help prevent dry skin, irritated sinuses, static electricity, And damage to wooden furniture or musical instruments caused by overly dry air.
HVAC Load Calculation is a detailed process that determines how much heating or cooling a building needs to stay comfortable year-round. It considers factors like room size, insulation, windows, occupants, And local climate to size equipment correctly and avoid energy waste or poor performance.
Indoor Air Quality is the condition of the air inside buildings and structures, especially as it relates to the health and comfort of occupants. Indoor Air Quality measures pollutants such as dust, mold, pollen, carbon monoxide, And volatile organic compounds (VOCs), as well as temperature, humidity, And ventilation levels. Poor Indoor Air Quality can cause headaches, allergies, fatigue, And long-term respiratory issues.
MERV Rating is a standardized scale from 1 to 20 that measures how effectively an air filter captures dust, pollen, mold spores, And other airborne particles. Higher MERV Ratings indicate finer filtration, meaning the filter traps smaller particles and improves indoor air quality in homes and businesses.
Minimum Efficiency Reporting Value is a standardized number that shows how well an air conditioner or heat pump filters particles from the air. Higher MERV ratings mean better filtration, But they can also reduce airflow if the HVAC system isn’t designed to handle them. The scale ranges from 1 to 20, with most home systems using ratings between 5 and 12.
NATE Certification is an independent, industry-recognized credential that proves HVAC technicians have passed rigorous exams testing their knowledge of heating, ventilation, air conditioning, And refrigeration systems. NATE stands for North American Technician Excellence, And certification covers core skills like installation, maintenance, And repair of HVAC equipment.
North American Technician Excellence is an independent, non-profit organization that certifies HVAC and refrigeration technicians through standardized exams. These exams test practical knowledge and skills needed to install, maintain, And repair heating, ventilation, air conditioning, And refrigeration systems safely and efficiently.
Pounds per Square Inch is a unit of pressure that measures the force applied by one pound of weight on an area of one square inch. It shows how much push or pull a fluid or gas exerts inside pipes, tanks, Or HVAC systems. Higher values mean stronger force; lower values mean weaker force.
Programmable Thermostat is a digital device that automatically adjusts a home’s heating and cooling settings based on preset schedules. It replaces a manual thermostat, allowing users to set different temperatures for different times of day, reducing energy waste when no one is home or during sleep hours.
PSI is a unit of pressure that stands for 'pounds per square inch.' It measures how much force pushes against one square inch of area. In HVAC systems, PSI shows refrigerant pressure, air duct pressure, Or water pressure in pipes. Correct PSI keeps heating and cooling equipment safe, efficient, And long-lasting.
Refrigerant is a chemical substance used in air conditioning, refrigeration, And heat pump systems to absorb heat from indoor air and release it outdoors. Refrigerants circulate through coils, changing from liquid to gas and back, to transfer heat efficiently. Common types include R-410A, R-134a, And R-32, each with specific properties and environmental impacts.
Seasonal Energy Efficiency Ratio is a standardized measure of how efficiently a central air conditioner or heat pump cools a home over an entire cooling season. It calculates the total cooling output in British Thermal Units (BTUs) divided by the total electrical energy input in watt-hours, reflecting real-world performance in warm climates like Texas.
Thermostat is a temperature-sensitive control device that automatically regulates heating and cooling systems to maintain a set indoor temperature. Thermostats detect ambient air temperature and signal HVAC equipment to turn on or off, ensuring consistent comfort and energy efficiency in homes and buildings.
Ton of Refrigeration is a unit of measurement used to describe the cooling capacity of air conditioning and refrigeration systems. It represents the amount of heat energy removed by a system to freeze one ton (2,000 pounds) of ice in 24 hours, equivalent to 12,000 British Thermal Units (BTUs) per hour. This standard helps size HVAC equipment for homes and buildings.
Two-Stage Furnace is a type of gas furnace that operates at two distinct heating levels: a low stage for mild weather and a high stage for colder temperatures. This design allows the furnace to adjust its output automatically, improving energy efficiency and maintaining more consistent indoor temperatures compared to single-stage furnaces.
UV Air Purifier is a device that uses ultraviolet (UV) light to kill or deactivate harmful microorganisms like bacteria, viruses, And mold spores in indoor air. UV Air Purifiers are installed inside HVAC systems to continuously clean the air as it circulates, improving indoor air quality without adding chemicals or filters that need frequent replacement.
Variable Speed Motor is an advanced electric motor used in HVAC systems that adjusts its rotational speed continuously rather than running at fixed speeds like single-speed or two-stage motors, So you can the motor to match airflow or cooling/heating demand precisely, improving energy efficiency, comfort, And system longevity by reducing frequent starts and stops.
Zoning System is a heating and cooling setup that divides a home or building into separate areas, Or zones, each controlled by its own thermostat. Zoning systems use dampers inside the ductwork and multiple thermostats to direct conditioned air only where it's needed, improving comfort and energy efficiency.
