You’ll want to look for a manufacture date. This is usually found on a label on the outside of your system.
If your unit is less than five years old, it may still be protected by a warranty. Having said that, warranty terms and conditions vary between manufacturer and installing company.
At Air Engineers Service Experts, we can confirm your warranty standing with a system inspection. We also provide HVAC service memberships in Jacksonville for residential heating and cooling equipment, regardless of equipment age or manufacturer warranty standing.