You’ll want to find the date it was made. This is usually situated on a label on the outside of your system.
If your system is less than five years old, it might still be warrantied. At the same time, warranty terms and conditions vary between manufacturer and installing company.
At Wesley Wood Service Experts, we can check your warranty state with a system inspection. We also provide HVAC service memberships in West Chester for residential heating and cooling units, regardless of system age or manufacturer warranty status.