You’ll want to check for a manufacture date. This is usually located on a label on the surface of your unit.
If your unit is under five years old, it might still be protected by a warranty. Having said that, warranty terms and conditions differ manufacturer and installing company.
At Parker Pearce Service Experts, we can check your warranty state via a system inspection in Gaithersburg for residential heating and AC units, regardless of equipment age or manufacturer warranty standing.