Underground ductwork is becoming more and more common in recent years. This is because there are several advantages of running your ductwork underground. This allows for reduced costs in the long run. Underground ductwork does not have to be insulated in most cases, since there is not air exposure. This removes a common area of failure from your system. This system will also allow you to run HVAC for multiple buildings from one central location rather than having multiple units for each building and having to place them all. Here are just a couple of things to think about when you are deciding on an underground ductwork system.
Buried or Cemented?
This is going to be a decision to make early on. Do you want your system buried or would you rather have it cemented? The best choice is to have your ductwork cemented, but this can add thousands to installation costs. The advantages here though are numerous. You don’t have to worry about your ductwork being damaged from outside, since it is encased in concrete for one. Another major advantage is that it is not going to wear out over time like ductwork that is buried in the ground can. A buried system is constantly exposed to moisture which can shorten its life.
Materials
Making sure you choose the right materials is another very important decision you must make. You will have to choose between rigid or flexible piping. Yes, in some instances you must use flexible piping, but for the most part you can choose. Flexible piping has the advantage of being able to bend and flex, but it is not as structurally strong as rigid piping. Rigid piping is going to stand up to a lot more abuse that flexible piping, but it is not going to flex, so if you live in an area where earthquakes are common you may be better served with flex pipe.