Air ducts are the hidden highways allowing conditioned air to circulate throughout the home. These ducts suck in air from the house and send it to the HVAC unit, which changes the temperature before returning it through return vents.
Dirty ducts can cause problems such as high energy bills and uneven temperatures in rooms. Other problems include dust buildup, musty odors, and rodent droppings.
Air Handler
The air handler is the indoor component in two-part HVAC systems that keep you comfortable throughout your home. It is often located in the attic or basement and closely resembles a gas furnace.
An air handler uses a blower to draw in unconditioned outdoor air through return ducts. This air may be warm, cool, humid, or full of particulates. The blower also creates noise that could disrupt your indoor comfort. To minimize noise and vibration, a sound attenuator is commonly installed.
The air handler blows this incoming air over a cold evaporator coil to cool it down. This air is then blown into the building through supply ducts. It is filtered through an air filter to remove pollutants and particulates before it is distributed. During this process, condensation forms on the inside of the air handler. Drain pans and lines remove this moisture to prevent rust and corrosion. This is essential for efficient heating and cooling because damp conditions can cause damage to the duct system.
Plenum
The plenum is the gateway for air to enter your ductwork system and reach various areas of a building for heating or cooling. It receives conditioned air from the main HVAC unit and distributes it to various areas. As the air circulates, it travels through a return duct and back to your furnace or HVAC unit. This air is then re-conditioned to heat or cool your home or office. The plenum also contains air filters, which must be kept clean to prevent clogging and promote proper airflow.
An efficiently functioning plenum reduces energy consumption by minimizing air leaks and optimizing airflow distribution. It also helps maintain consistent temperature levels, which benefits occupants and increases the longevity of HVAC equipment.
Despite their many benefits, plenums can be vulnerable to damage and failure. Often, these air distribution systems can get obstructed or dislodged. When this happens, it is important to call a professional to inspect and repair your plenum box. The technician will ensure that your plenum is properly fitted, seals any holes or leaks, and is connected to your ductwork correctly.
Smoke Damper
A smoke damper is an active fire protection system installed in air ducts and wall openings that penetrate or terminate within a physical smoke barrier. It closes automatically when triggered by smoke or fire detectors. These systems can also be activated by a signal from the fire alarm control panel.
They are a crucial component in controlling the spread of smoke and supporting evacuation and firefighting efforts. Smoke dampers are important because they can keep occupants safe by limiting the smoke that enters areas where there is a danger of inhalation. They can also help maintain visibility in critical areas, making it easier for firefighters to navigate the building and extinguish the fire.
These dampers are actuated by either an electric or pneumatic actuator that is powered by air. When a smoke or fire signal is received the damper’s blades rotate to close the duct opening and form a smoke seal. A closed position indicator switch is connected to the damper to display its status in a fire command center or a separate panel. The system is protected by a high-limit temperature sensor that prevents the damper from reopening until the duct temperature has been reduced below the UL555S degradation test temperature.
Takeoffs
Takeoffs are metal fittings that connect the mother duct to every subsidiary branch. They are stationed in circular or rectangular holes drilled into every subsidiary duct. These takeoffs are a key to the even distribution of airflow in HVAC systems. Poor takeoffs can lead to hot or cold spots in a building, not to mention unbalanced air pressure and reduced system lifespan.
There are several types of takeoffs to choose from, and each has its benefits. The simplest of these is the round takeoff, which can be constructed from scrap sheet metal pipe or elbow. This takeoff is the most cost-effective, but it can create an airflow penalty. The next step up is the conical takeoff, which is wider at the base than it is at the branching size. This takeoff can be slipped over a reducer collar, which makes it even more cost-effective.
Finally, there is the high-efficiency takeoff (HETO), which is designed to transition from rectangular to round duct and includes a pre-installed balancing damper for enhanced airflow performance.
Insulation
Insulating your ductwork prevents energy loss by sealing leaks and minimizing heat transfer between the conditioned air in your house and the outside air. This reduces the strain on your HVAC equipment and lowers your energy bills. Duct insulation can also reduce annoying indoor noises like rattling, buzzing, and whistling.
Insulation for ductwork is available in several different formats. The most common is fiberglass insulation which has an outer foil that keeps the fibers intact and is available in either preformed rolls or in loose form. A trained insulation installation professional can help you choose the right type for your project.
Air duct insulation should not be installed inside the ducts themselves, but rather on the exterior of the ductwork in an attic or other suitable space. It’s important to use the proper R-value for your climate and location. In addition, it is a good idea to consider using sustainable insulation which includes rubberized asphalt self-healing and acrylic adhesion systems for cold-weather installations. This helps to prevent moisture infiltration that could lead to mold, condensation, and corrosion in the duct system.