Here's an industry truth that should be printed on every quote: the installation determines more of an air conditioner's lifespan than the brand does. Two identical units, one installed carefully and one rushed, will live very different lives. So instead of a brand debate, here's what a proper replacement day includes — the checklist we work from, and the one you're entitled to ask any installer about.
Before the old unit comes out
The refrigerant in your old system gets recovered into a cylinder with a recovery machine — it's federal law, and it's also the first honesty test of any crew (venting it to the sky is faster, illegal, and still happens). Then sizing: a replacement should be sized to the house's actual load, not automatically to the old unit's sticker — homes get new windows and insulation over 15 years, and the oversized units of past eras short-cycle and dehumidify poorly.
The details that decide the lifespan
Line set: reused lines get flushed and pressure-verified, or replaced when the refrigerant change or condition demands it — old oil and debris are compressor poison. Brazing with nitrogen flowing: brazing copper without nitrogen inside creates oxide scale that circulates through the new system like sand; you can't see this corner being cut unless you know to look for the nitrogen rig. The deep vacuum: after assembly, the system gets evacuated to a measured deep vacuum — verified with a micron gauge, held to prove tightness — because moisture left inside forms acids that eat compressors slowly. Weighed-in charge: refrigerant added by scale to the manufacturer's spec, then verified by measured performance numbers, not "feels cold."
The supporting cast
A new pad or leveled mounting, a new disconnect and correctly sized breaker/fuses, a new filter drier (non-negotiable on any opened system), condensate handling checked, and a commissioning sheet with the measured numbers — pressures, temperatures, amp draws — that becomes the baseline for every future service visit.
What you should walk away with
A system that cools quietly at its rated capacity, paperwork with real commissioning numbers, registration for the manufacturer's warranty, and a written price that didn't move between quote and invoice. Around here the replacement conversation increasingly includes the heat pump option — same install day, and it covers your heating too; we'll price both so the decision is yours with numbers on the table.