You’ll want to look for a manufacture date. This is typically located on a label on the exterior of your unit.
If your system is less than five years old, it could still be under warranty. However, warranty terms and conditions vary between manufacturer and installing company.
At R & M Climate Control Service Experts, we can check your warranty standing through a system inspection. We also offer HVAC service memberships in Knoxville for residential heating and AC units, regardless of equipment age or manufacturer warranty status.