By Robert Patterson · Reviewed by Robert Patterson, TDLR-licensed · Last updated Jul 23, 2026
The short answer: replacing a full AC or heat pump system typically needs a mechanical permit inside incorporated cities; a straight repair typically does not. If you're unsure, your licensed contractor should know your AHJ's rule cold — and pull the permit for you.
Repair vs. replacement
Swapping a failed part is maintenance; swapping the equipment is an installation the code cares about. If you're deciding between the two, our one-third rule guide helps — and either way, we tell you up front whether a permit applies.
Why the permit actually helps you
A permitted job gets an inspection, which is a second set of eyes confirming the install meets code. It also protects resale (unpermitted work can surface at closing) and can protect your manufacturer warranty, which assumes a code-compliant, professional install.
The trap to avoid
A too-cheap bid that skips the permit to save time. You inherit the liability, the resale headache, and any code problems. See how permitting works across our counties for the jurisdiction details.
Your next step
Ask us before you buy — we'll confirm your city's requirement and handle the paperwork on your replacement. Request a quote or explore the Learning Center.
General information, not legal or code advice. Requirements vary by jurisdiction and change over time — confirm with your local building department (AHJ). Reviewed by Robert Patterson, TDLR-licensed, July 2026.