What are HVAC air ducts, and how do they work in your home?
HVAC air ducts are tubes that transport heated or cooled air throughout your house and stand for Heating, Ventilation, and Air Conditioning. Most homes have two main types of ducts: supply and return, which work together to maintain seamless air circulation in your home throughout the year for your comfort.
Here are some important details about HVAC air ducts:
- Supply ducts push air out: Supply ducts remove warm or cool air from the system and circulate it into your rooms.
- Return ducts pull air in: Return ducts take indoor air back to the system to heat up or cool down.
- Ducts are typically made out of a metal sheet or fiberglass to make it easy to go through walls, floors, and ceilings.
- Cleaner ducts are equal to better air. Simultaneously, dirt buildup on ducts can lead to allergens, trash buildup, and bad airflow.
- Leaky ducts waste energy: You can lose up to 30% of air through leaks from holes or connections that are not secure.
When ducts are installed properly, they can provide efficient HVAC system performance, save energy, and improve indoor air quality.
What does an HVAC return duct do, and why is it important?
An HVAC return duct has one primary purpose, and that is to pull indoor air back into the HVAC system to be filtered, conditioned, and recirculated. If there are no return ducts, an HVAC system runs inefficiently due to a lack of properly balanced air distribution.
Some major characteristics of return ducts and why they are crucial:
- Returning Air: Allows for airflow to be maintained for efficient heating/cooling.
- Air Filtration: Assists in trapping dust, allergens, and dirt before recirculation.
- Temperature Control: Helps to prevent uncomfortable hot/cold spots in different areas of the house.
- Proper Airflow Balance: Return ducts aid in maintaining the balance of airflow in your house. This prevents air pressure from rising or falling too much, which could cause temperature imbalances and poor airflow.
- HVAC Efficiency: An HVAC system can overheat or freeze up without a return air duct.
If your home feels stuffy, dusty, or temperature imbalance in certain areas, it may be due to blocked, undersized, or improperly fitted return air ducts.
Have you ever thought about the process of airflow in your system? Basically, it is a cycle performed by the supply vents and the return ducts of the HVAC system. Supply air is nothing but the cooled or heated air blowing from the system via the supply air vents. But from where and how does this air come from?
The return air ducts collect the conditioned air. They then send it to the indoor AC air handler to heat or cool it again. This air duct returns the air in a cycled way for unobstructed airflow and, hence, named so. Therefore, it is pivotal to install the return air ducts rightly at the time of ac installation.
Why are return air ducts necessary?
The main job of an HVAC return air duct is to gather indoor warm air from the room. It then sends this forced air to the AC blower. This released air is cooled by the air conditioning system, and then the cooled air is finally released from the air vents. This process works in a cycle, maintaining the air pressure, proper circulation and the temperature set on the thermostat.
The most suitable location of a cold air return ductwork is the area receiving the best airflow. Choosing the right place for a return duct is important. If these ducts are inefficient, the system will not work properly.
How do I choose the suitable places to install a return duct?
As said earlier, choosing the right place to install the return ducts is essential for the correct airflow of the system. Firstly, you have to observe in which areas of your house there is the maximum level of airflow. Make that area your priority to install the return ductwork.
Also, we should note that high-traffic areas, such as hallways or living rooms, have natural airflow. Hence, they are suitable to capture the air for cooling the other rooms.
One of the most important things to keep in mind is to install the return ducts away from supply vents. In the supply ducts, the air returns too quickly. Therefore, installing the return vents in those areas will pose a risk of short-circuiting. The system will also degrade energy efficiency and provide improper heating and cooling or ac short cycling.
Never obstruct the path of return ducts with furniture or other things. This will not permit the return ducts to capture air smoothly.
Balancing the return air
Proper balance of the return ducts is pivotal for the smooth running of the HVAC system. Balancing of the ducts ensures that the system provides uninterrupted heating or cooling and prevents negative pressure. The balance of the return air vents majorly depends on the two following things:
Proper duct sizing: Return ducts should be of proper sizes for smooth airflow of the system. An undersized ductwork will obstruct air flow of the return grilles, and an oversized ductwork will not adjust with the system.
Proper duct placement: Place the ducts correctly to capture air from all areas of the room.
Size of return air ducts
The standard size for round return air ducts in homes is between 6 inches and 14 inches in diameter. On the other hand, rectangular air ducts range from 8 × 10 inches and 14 × 24 inches in dimensions. The return air duct size depends on the sizes of the air ducts as well as the size of the HVAC unit.
For the installation of one or two return vents for a 2-ton AC unit, you need a 12 inch return ductwork. Using 14-inch, 16-inch, and 18-inch return ducts for 3-ton, 4-ton, and 5-ton units is also good.
Cleaning of the return air ducts
Keeping the return air ducts clean is crucial as they circulate the air throughout your home. If they get dirty, the indoor air quality will worsen. This will also reduce the system’s overall performance. Here are some tips for cleaning the return ducts:
- Routine HVAC maintenance
Clean the air filters regularly to prevent any dust and debris buildup in the duct systems. Clean and change air filters once every three months so that they don’t get clogged.
- Professional duct cleaning
A professional technician uses special HVAC equipment and cleaners to remove any dust or mold from the ductwork. Schedule at least one commercial ductwork cleaning service every 3 years. You need a more frequent cleaning service if you have pets or you live in a dusty area.
- Repair any leaks
Regularly inspect for any leaks or cracks in the ducts, as they will allow dust and debris to enter. Seal any leaks found with a metal tape or duct sealant.
- Keep the surroundings clean
Ensure that the environment around the ductwork remains clean and free of dust and other contaminants. Regularly vacuum the area and keep the surrounding furniture clean and healthy.
- Install a return duct cover
If your ductwork is exposed or accessible, you should install a cover to protect it from dust and debris buildup. Installation of a duct cover can be a DIY job.
You have to go to the area where you cut the hole for the return vent. Adjust the cover and place it upon the holes with the help of screws and screwdriver. Make sure to fully cover the vents.
