You’ll want to look for a production date. This is typically situated on a label on the outside of your equipment.
If your system is newer than five years old, it could still be protected by a warranty. Having said that, warranty terms and conditions vary by manufacturer and installing company.
At Service Experts Commercial HVAC, we can check your warranty standing through a system inspection. We also have HVAC service memberships in Toronto for residential heating and AC units, regardless of unit age or manufacturer warranty status.