There are many parts of a basic air conditioning unit for homeowners, and most people rarely have to think about their AC unit unless it needs repaired. For the HVAC technician, it's important to understand what options you have when repairing or installing your customer's AC unit. One fundamental part of AC units are the air ducts. Of these, there are the fiberboard ducts, the sheet metal ducts, and the flexible ducts.
Fiberboard ducts are air ducts made out of glass fibers compressed together and bound together with a resin. These rigid ducts are sealed on the inside to prevent fiberglass from reaching the AC system, and the exterior is typically a foil meant to prevent external elements from reaching the ducts and internal air from escaping. They are typically inexpensive and can be made for the specific requirements of your consumer's home. However, the surface is typically rough, leading to a less aerodynamic system than other ducts.
Sheet Metal Ducts
Sheet metal ducts are an incredibly durable choice for the HVAC installer. These air ducts are made from either galvanized steel or aluminum and easily protect the system from the elements. Sheet metal is non-porous and therefore the most resistant to mold or or other growth. They are frequently light and easy to install, but they need to be thick enough to prevent damage from any weight being applied to them. Additionally, they are rigid. If flexible air ducts are needed for your consumer's cramped home space then neither sheet metal ducts nor fiberboard ducts will be the right choice for your job.
Flexible air ducts are a great option for some kinds of spaces used for air conditioning installation, so long as care is taken to ensure the best possible performance of the AC unit. Because they are not rigid, they must be properly supported to prevent sagging or unwanted bends. Additionally, the less bends or kinks used in construction of the entire AC unit, the better your unit's air flow will be. These air ducts are extremely easy to install, and have none of the risk of that fiberglass can entail.
Finally, in addition to all of these option, you can also line your chosen air ducts with fiberglass for better insulation and protection. Fiberglass lined air ducts also help reduce the noise of the AC unit whether they are applied to the inside or the outside of the chosen air duct. However, when installed inside the air duct, they can collect mold easily as fiberglass sucks up more condensation than other duct materials. Over time, the seal above fiberglass will erode and cause tiny fiberglass particles to break off from the duct itself and move into the air of the building, leading to a variety of health concerns including rashes, eye irritation, soreness of the nose and throat, and an increase in asthma symptoms. If your air duct interior is lined with fiberglass then regular maintenance is required.
Air ducts are an important part of the air conditioning process and without them, cooled air won't reach your consumers homes nor will stale air be cycled out. There are many options for your air conditioning installation needs, with a wide range of benefits and drawbacks. Be sure to do your research and conduct a careful review of your and your consumer's needs before choosing your air conditioning ducts.