International. Carrier Enterprise (CE) shared an interesting analysis on best practices for pipeline design and installation. A high-efficiency HVAC system depends on properly designed and installed ducts. Nate Zuck, CE's Customer Assurance Manager, makes an analogy when comparing an HVAC system to blood flow in the human body. He says, "HVAC equipment is the heart, but it's useless without a good circulatory system." In this case, the circulatory system would be the duct.
He adds: "If your arteries (ducts) have restrictions, the heart (HVAC equipment) has to pump much harder to overcome the pressure. This vascular disease will make the patient (building) feel unwell and will lead to expensive long-term care (repairs) and premature failure of the heart (equipment)."
Clearly, duct design is crucial to an efficient HVAC system. By following these five best practices for duct design, you can ensure that you are installing the most efficient HVAC system possible for your customers.
1. Use only approved duct materials
Before you can even think about installing ducts, you need to make sure you are using only the approved materials that were made to be permanent. Sheet metal is the most common material for ducts, as it is lightweight and easy to handle. However, flexible fiberglass ducts are becoming increasingly popular due to their built-in insulation and malleability.
2. Place the duct strategically
Location is key when it comes to successful pipeline design. If possible, avoid ducting in crawl spaces, attics, or basements. These areas provide very little insulation and can experience massive temperature fluctuations throughout the year. This means that the HVAC system has to work harder to maintain the correct temperature, and it also means that the homeowner will pay for hot and cold spaces that they rarely visit.
3. Ensure a balanced air pressure
When it comes to duct design, having an equal amount of air return and air supply is crucial. If the air pressure is unbalanced, your customer will experience higher energy bills and a lower comfort level. To maintain a balanced air pressure in the duct installation, try to have a return grid in each room that has a supply record. If that's not possible, you should have a minimum of at least one return grid at each level of the living space. Something else to consider in duct design is how closed doors impact airflow. Be sure to use bridge ducts and transfer grids to overcome these barriers and ensure free airflow.
4. Make sure the duct fits perfectly into the space
One of the most common mistakes in the installation of ducts is the use of ones that are too small or too large. If it is too small, it can cause excessive noise, lack of air balance, and too much static pressure. Conversely, if the duct is too large, it sinks, which has a dramatic impact on the efficiency of the HVAC system.
5. Install iron seals and test them
Finally, all seals must be extremely tight. This step can save the homeowner nearly 20% on their energy bill by eliminating air leakage out of the HVAC system. To properly seal metal ducts, use metal sheet screws, along with putty paste and heat-proof metal tape. In flexible fiberglass ducts, you can use collars and straps of suitable size to seal the connections. For the two largest HVAC connections, the trunk and the plenum, use an expansion collar. And always test each stamp before considering the job done.
