Duct Design Terms

Custom duct design refers to the creation of tailored ductwork solutions specifically crafted to meet the unique requirements of an HVAC system and the architectural layout of a building. These designs are engineered to optimize airflow, energy efficiency, and system performance while accommodating the building's specific heating, cooling, and ventilation needs.

An HVAC system stands for Heating, Ventilation, and Air Conditioning. It is a technology used to manage indoor air quality, temperature, and humidity in residential, commercial, and industrial buildings. Proper ductwork design is critical to ensure the HVAC system operates efficiently and effectively.

An air duct is a passage or conduit used within HVAC systems to transport air for heating, cooling, or ventilation purposes. Properly designed air ducts are essential for maintaining even airflow, reducing energy loss, and enhancing indoor air quality.

Ductwork fabrication involves creating customized ducts from raw materials such as sheet metal or flexible materials. The process ensures the ducts fit the specific dimensions and configurations required for a building's HVAC system.

Sheet metal ducts are durable and rigid ducts made from materials like galvanized steel or aluminum. They are commonly used in residential, commercial, and industrial HVAC systems due to their strength, durability, and resistance to environmental wear and tear.

Energy efficiency in duct design involves creating systems that minimize energy loss during air transportation. This includes the use of proper insulation, sealing, and design strategies to reduce waste and optimize the performance of HVAC systems.

Airflow optimization is the process of designing and configuring duct systems to ensure an even and efficient distribution of air throughout a building. Proper optimization helps in maintaining consistent temperatures and improving energy efficiency.

A duct layout plan is a detailed schematic that outlines the design, placement, and routing of ducts within a building. These plans are critical for ensuring efficient airflow and proper system integration with the HVAC unit.

A zoning system divides a building into different sections or 'zones,' allowing for independent temperature regulation in each area. Custom ductwork plays a key role in ensuring that each zone receives the appropriate amount of airflow for optimal comfort and efficiency.

Duct insulation involves adding material around ducts to reduce energy loss, prevent condensation, and improve the efficiency of HVAC systems. Insulation helps maintain the desired air temperature as it moves through the ducts.

Duct sealing is the process of closing leaks and gaps in ductwork to improve energy efficiency and airflow. Proper sealing ensures that conditioned air reaches its intended destination without being lost through leaks.

Indoor air quality refers to the health and comfort of the air inside buildings. Proper duct design and maintenance play a crucial role in enhancing IAQ by preventing the buildup of dust, mold, and other pollutants.

Flexible ducts are made from flexible plastic and wire, making them ideal for installations in tight or hard-to-reach spaces. They are versatile and easy to install but require careful design to avoid airflow restrictions.

Rigid ducts are sturdy and durable ducts typically made from sheet metal. They are known for their long-lasting performance, resistance to damage, and superior airflow capabilities compared to flexible ducts.

A ventilation system is a network of ducts, fans, and other components designed to circulate, filter, and exchange air within a building. It plays a crucial role in maintaining healthy indoor air quality and temperature control.

Duct cleaning is a maintenance process that involves removing dust, debris, and contaminants from the interior of ductwork. Regular cleaning helps improve airflow, energy efficiency, and indoor air quality.

Static pressure is the resistance to airflow within a duct system, which impacts the efficiency and performance of HVAC systems. Proper duct design minimizes static pressure and ensures optimal system functionality.

Return ducts are components of a duct system that carry used or stale air back to the HVAC unit for reconditioning or expulsion. They are essential for maintaining balanced air circulation within a building.

Supply ducts deliver conditioned air from the HVAC system to different rooms or zones within a building. Properly designed supply ducts ensure even distribution of air for consistent temperature control.

A plenum box is a central air distribution component in a duct system. It connects the HVAC unit to multiple ducts and helps evenly distribute conditioned air throughout the building.

Duct balancing involves adjusting the airflow in a duct system to ensure that every room in a building receives the correct amount of air. This process is crucial for maintaining consistent temperatures and improving HVAC system performance.

Air leakage occurs when conditioned air escapes through gaps or cracks in the ductwork. Minimizing air leakage improves energy efficiency and reduces costs.

Static regain is the recovery of static pressure within a duct system. Proper duct design considers static regain to optimize airflow and system efficiency.

Grilles and registers are the vents that allow air to enter or exit a room from the duct system. They play an important role in directing airflow and maintaining comfort.

Pressure drop refers to the reduction in air pressure as it flows through a duct system. Excessive pressure drop can negatively affect HVAC performance.

Duct fittings are components such as elbows, tees, and reducers used to connect sections of ductwork. These fittings help direct airflow and accommodate changes in direction or size.

The return air plenum is the area in an HVAC system where air is collected before being returned to the system for conditioning or expulsion.

Duct sizing is the process of determining the appropriate dimensions of ductwork to ensure efficient airflow and energy use within an HVAC system.

Sound attenuation in ductwork involves designing systems to minimize noise generated by airflow, fans, or equipment within the HVAC system.

Thermal conductivity is the ability of duct material to conduct heat. Materials with low thermal conductivity are preferred for energy-efficient duct systems.

Round ducts are a type of ductwork known for their efficient airflow and reduced resistance compared to rectangular ducts.

Rectangular ducts are flat ducts commonly used in commercial and industrial buildings due to their space-saving design and ease of installation.

Duct transitions are fittings that connect ducts of different sizes or shapes. They ensure a smooth flow of air through the duct system.

Fire dampers are safety devices installed in duct systems to prevent the spread of fire and smoke through HVAC systems.

Air filtration in duct systems involves removing particles and pollutants from the air as it flows through the HVAC system, improving indoor air quality.

Damper control refers to the regulation of airflow within a duct system using devices that open or close sections of the duct.

Duct rehabilitation involves repairing or upgrading existing ductwork to improve efficiency, performance, and lifespan.

HVAC load calculation is the process of determining the heating and cooling requirements of a building, which influences the design of the duct system.

Conditioned air refers to air that has been heated, cooled, or filtered by an HVAC system and is distributed through ductwork to maintain indoor comfort.

Flexible insulated ducts are a type of ductwork that combines flexibility with insulation to minimize energy loss and adapt to complex layouts.

Usually, it is a solid substance with the ability to take up or absorb another substance (usually in gas).

American Society of Heating, Refrigerating, and Air-Conditioning Engineers www.ashrae.org.

An azeotrope (or azeotropic mixture) is a mixture of two or more liquids that behaves as a single substance when boiled, meaning its composition remains unchanged during phase transitions (boiling or condensation). This occurs because the vapor has the same ratio of components as the liquid, preventing separation by simple distillation.

Since azeotropes cannot be separated by conventional distillation, special separation techniques like azeotropic distillation, pressure-swing distillation, or adding entrainers are used to break the azeotropic behavior.

Component providing heat transfer to air when mounted inside an air handling unit or ductwork. The termis normally associated with a fin and tube heat exchanger using refrigerant or water as the heat transfer medium.

A vessel or an air cooled coil that removes the superheat of compression, condensing the refrigerant gas into a high pressure liquid.

Part of a refrigeration/air conditioning system comprising a compressor, motor and condenser heat exchanger; supplied as a single unit to be matched with a suitable evaporator. Also see Condensers & Condensing Units.

The transfer of heat by the movement of electrons or by the vibration of molecules through contact of two or more bodies of differing temperatures

A modulating device for controlling airflow rates through ductwork or air handling equipment.

The process of removing moisture from the air within a conditioned space to maintain the required humidity level.

Refers to a type of air conditioning system that discharges air downward, directly beneath a raised floor, commonly found in computer rooms and modern office spaces.

Ducts are used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air including supply air, return air, and exhaust air.

Electronically Commutated (EC) fans use brushless DC motors which include in-built electronics to convert the AC supply to DC without the need for a separate DC supply. EC fans provide a more efficient (up to 30%) means of airflow through Precision Air Conditioning (PAC) units with the additional benefit of variable speed control via an output signal from the unit controller. Also see EC Fan upgrades.

An economiser is a mechanical device used to reduce energy consumption. Economisers recycle energy produced within a system or optimise environmental temperature differences to achieve efficiency improvements.

Energy Efficiency Ratio (EER) is a measure of system efficiency at a given set of rating conditions. It is a ratio calculated by dividing the cooling capacity in kW by the power input in kW.

An evaporator coil is usually located indoors as part of a split unit or within an air handler or duct system. Inside the coil, refrigerant evaporates as it absorbs heat from the air that passes over it.

A fan coil unit (FCU) is normally a chilled water device consisting of a heating and/or cooling coil, fan, valve/s and local controller. It forms part of a larger HVAC system found in residential, commercial, and industrial buildings.

This may apply to a system using fresh air for cooling the space or a water cooled or glycol cooled system with an additional coil that provides chilled water cooling when the outdoor ambient is cold; thereby reducing or eliminating compressor operation. These systems may provide free cooling for up to 80% of their operating life, particularly when operating in Northerly climates. See our Free Cooling page for more information.

A type of air conditioning system using a water/glycol solution as a condensing medium. Typically, the glycol-cooled condenser is located inside the air conditioner with the rest of the refrigeration components. Water/glycol is piped to the unit from a drycooler or other suitable source. The glycol keeps the solution from freezing during winter operation.

The amount of heat needed to raise the temperature of a given mass by 1 degree Kelvin.

A heat pump is a mechanical device that absorbs low grade heat from a lower temperature location andupgrades and transfers the resultant higher temperature medium, created by mechanical work, to heat aspace to a sufficient comfort level. Heat pumps may be air to air, air to water, water to water or ground towater.

Heat transfer describes the exchange of thermal energy between two interacting media passing through a heat exchanger, such as refrigerants, air and water.

The process of adding moisture to the air within a space.

HVAC (heating, ventilation, and air conditioning) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality.

The amount of energy added or removed from the air in order to increase or reduce the moisture content of the air during the air conditioning process. It is measured in kg/kg of dry air.

Intake supply fan to replace air exhausted from a building. MUA may be heated or cooled so that the air coming in does not have a major impact on the building air conditioning systems, but is not designed to cool or heat the building.

A self-contained air handling unit made specifically for outdoor installation; it includes all heating and cooling devices pre-assembled prior to installation.

A split air conditioning system consists of two main parts: the outdoor (condensing) unit and the indoor unit. Although any size of unit could be defined as a split system it normally refers to smaller equipment, specifically air to air heat pumps.

Values of parameters that define indoor air quality, thermal and acoustical comfort, energy efficiency and the associated system controls that should be achieved by the design.

Fan performance is controlled by means of a damper, either on the inlet or on the outlet, creating a variable additional system resistance. (EN 12792)

Vanes mounted at the fan inlet, which can be adjusted in order to change the fan performance by controlling the swirl at the fan inlet. (EN 12792)

Device for removing particulate material and gases from air. Buy Here.

The filter rack is designed to be installed between the side of the furnace and the return air duct, and usually requires some basic transitioning unique to each application. Changing your air filter regularly can help to avoid a lot of problems and ensures your furnace blower is not overworked. Buy Here.

A self-contained heating unit that is designed to deliver heated air to a home. Buy Here.

Heat Recovery Ventilator is a machine that brings fresh air into a home through a process that preheats the air so it has less impact on your utility bill. Buy Here.

Hydroflorocarbon, used as a refrigerant in air conditioners and heat pumps. It has little or no effect on the ozone layer.

The energy that suspends moisture vapor in the air.

A mathematical determination of how much cooling and heating (BTUs) an HVAC system must deliver for occupant safety and 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.

An ACCA procedure covering the proper design, installation, maintenance, and repair of ductwork.

An ACCA procedure covering the method for calculating heating and cooling requirements (load calculation) for single-family detached homes and mobile homes.

An ACCA publication covering the design, installation, and commissioning of a residential HVAC system.

The path the air takes to get to an air-handling unit or furnace so it can be cooled or heated. It is the “return” path. The return side should be “balanced” with the supply side to ensure proper air flow and comfort.

The temperature of the air. This type of heat is measured with a thermometer.

A two-component heating and cooling (heat pump) or cooling only (air conditioner) system. The condensing unit is installed outside, the air handling unit is installed inside (preferably in conditioned space). Refrigerant lines and wiring connect them together.

The part of an HVAC system that takes (supplies) the conditioned air from the airhandling unit or furnace to your home. The supply side should be “balanced” with the return side to ensure proper air flow and comfort.

A single HVAC system that can meet different heating and cooling needs in different areas (zones). Each zone of a home has its own thermostat with which it can regulate the temperature and humidity in its area. One “zoned air conditioner” could be set for a high temperature in one zone and for a lower temperature in the other zone. Zone systems have two or more zones.

An "angle boot" refers to a specialized duct fitting used in HVAC systems, designed to create a 90-degree transition between a round pipe and a rectangular register or grille, essentially allowing the airflow to change direction at a right angle

A straight boot is a type of duct boot used in HVAC systems to connect ductwork that runs straight and convert it into a vent.

An end boot is a fitting that changes ductwork into a vent. It's typically used at the end of a ductwork system. Buy Here.