Running Line Sets Underground – What You Need to Know

In most installations, refrigerant line sets are run along an exterior wall or through an attic space before connecting to the indoor air handler. This approach makes the system easier to install, maintain, and service over time.

We do not recommend running line sets underground. While it may seem like a cleaner or more discreet option, it can create challenges both during installation and throughout the life of your system.

If you do decide to install line sets underground, here are a few important considerations:

1. Protection is required
   Line sets must be installed inside a PVC chase or conduit. This helps protect them from soil pressure, shifting ground, rocks, or other factors that could cause the lines to become crushed or damaged.

2. Moisture and corrosion risks
   Underground environments naturally hold more moisture. Without proper protection, this can increase the chance of corrosion over time.

3. Future service and maintenance
   If a problem occurs—such as a refrigerant leak, restriction, or physical damage—your technician may need to access the underground portion of the line set. This often means digging up the buried section, which can be costly, disruptive, and time-consuming.

4. Long-term planning
   When choosing to bury line sets, understand that while the system may work initially, future maintenance will be more difficult. Planning for accessibility can save significant time and expense later.

In summary: We strongly recommend avoiding underground line set installations whenever possible. If it cannot be avoided, always run the lines through a properly sized PVC chase to protect them, and be prepared for the possibility of excavation if maintenance is needed in the future.