Answer first, context after
How do I know if my HVAC system is still under warranty?
Find the model and serial number on the outdoor unit's data plate, then run it through the manufacturer's warranty lookup page; every major brand has one. Two catches decide most cases: many brands grant their full parts term only if the system was registered shortly after install, and warranties often shrink when a home changes hands. Check before paying for any major repair.
A surprising number of homeowners pay full price for parts a manufacturer would have covered, simply because nobody checked. Five minutes with a serial number prevents that, so here is the whole procedure, plus the fine print that decides the borderline cases.
Step one, find the plates: the outdoor unit carries a data plate with the model and serial number, usually on the side or back of the cabinet. The furnace or air handler has its own, inside the front panel or on the cabinet. Photograph both; the serial is also how you date the system, which matters in a minute.
Step two, look it up: every major manufacturer runs a public warranty lookup where the serial number returns the coverage status. Search the brand name plus “warranty lookup.” If the website defeats you, text us the photos at (661) 374-0624 and we will run it, free, no visit required. We do this before every significant repair quote anyway, because quoting you for a part the manufacturer owes you is not a business we want to be in.
The registration catch: many brands ship with a base parts warranty, commonly five years, that extends to the full term, commonly ten, only if someone registered the system within the window after installation, often 60 to 90 days. Good installers register it for the homeowner; plenty never did. The lookup reveals which kind installed yours.
The home-sale catch: warranties frequently shrink or lapse when a house changes owners, with some brands offering a paid transfer within a deadline after closing. If you just bought the house, running the serial number belongs on the move-in list next to changing the filter, while any transfer window is still open.
What warranties never cover, so the invoice makes sense: parts warranties cover parts, not the labor to diagnose and install them, which is why a covered compressor still carries a real repair bill. Labor coverage comes from whoever installed the system, and it is why we ask every contractor question in writing: our installs carry 10 years parts and 2 years labor, our repairs 12 months, and the distinction sits in the quote where you can read it, not in a footnote where you find it later.
Still stuck? That's what the truck is for.
The diagnostic is $89, waived when you book the repair, with a written flat price before any work starts.