How long does an AC last in Houston?

The national figure for a central air conditioner is fifteen to twenty years. Houston is not the nation. A system here runs around three thousand hours a year, roughly two and a half times the national average, through humidity that corrodes coils and summers that keep the condenser working at the top of its range for months. Ten to fifteen years is the honest expectation, and a system that reaches fifteen in Houston has been looked after.

What shortens it: an oversized unit that short-cycles, a condenser in full afternoon sun with no shade, a coil that is never cleaned, a refrigerant charge that has been low for seasons, and ductwork so leaky the system never gets to rest. What lengthens it: a spring service every year, a clean condenser, a correct charge, a filter changed monthly in summer, and shade on the outdoor unit that does not block its airflow.

Heat pumps run both seasons and wear accordingly. Mini splits, being inverter-driven, often last longer than conventional systems because they rarely run flat out. Furnaces in Houston last a long time for the simple reason that they hardly run.