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