The ductwork system is responsible for distributing the conditioned and filtered air throughout your home and returning it back to your heating and cooling equipment. Properly installed ductwork will maintain an even temperature throughout the home, have minimal air leakage, and produce a negligible amount of noise. On the other hand, a poorly installed duct system will lead to hot and cold spots, cause higher utility bills from efficiency loss, and be a noise nuisance. The materials used, the design, and the installation practices determine the quality of the ductwork system.
Sheetmetal is without a doubt the best material… its durable, efficient, and quiet. However, this is very rarely used in the San Antonio residential market for a number of reasons including cost and framing designs. The majority of the market uses a combination of duct board and flex duct. These types of products work great if properly designed and installed, but something to think about is the different options within this product segment. Both duct board and flex duct are offered with different insulation values, and flex duct alone comes in a variety of specifications that affect the durability and efficiency. Be sure to know what products are being used and if they meet the local building codes.
How much air each room needs, the size of individual ducts, the type and size of supply and return grilles… are all design questions. It takes knowledge and experience to get it right, but most of the companies doing it right rely on the help of software. The starting point for every well-designed duct system is a Manual J (calculation to determine the heating and cooling loads of a home and individual rooms) and a Manual D (method used to determine the overall duct lay-out including the individual duct sizes). There are several industry approved software applications that help generate a Manual J and D, and ultimately a duct system “blueprint”. A contractor should be able to show you a detailed blueprint before ever installing a single duct.
The third leg of this barstool are the installation practices… how does part A connect to part B? This is the hardest component for a homeowner to evaluate. This involves all of the “little things” that a homeowner will never see… is the collar properly sealed, or is that back section that you can’t get to sealed? Of course, there are obvious indications as to the quality of the workmanship like the ducts being properly strapped up and the use of duct sealant around connections. A good contractor will be proud to show you their work and stand behind it with a warranty.
Just because you can’t see it doesn’t mean its not important. The most efficient air conditioning equipment will not fix a poor and leaky duct system. A properly installed duct system is a great investment for the health and comfort of your home.