Ductless Mini-Split

Definition

A mini-split is a heat pump with a different distribution method. Instead of ducting cooled or heated air from a central air handler through ductwork to room registers, it sends refrigerant through small (3/8" to 5/8") copper line sets to indoor head units mounted in each conditioned space. Each head has its own evaporator coil, blower, and thermostat — so each room is its own zone.

Three configurations are common in Austin: single-zone (one outdoor unit, one indoor head — typical for a garage conversion or ADU), multi-zone (one outdoor unit serves 2-5 indoor heads — typical for additions or whole-house ductless retrofits), and concealed-duct mini-split (an indoor head ducted to a small zone of a few adjacent rooms, when wall-mount aesthetics aren't acceptable).

Mini-splits use variable-speed inverter compressors as the standard (not optional), so they ramp up and down with load instead of cycling on/off. The result is exceptional humidity control and very even temperatures — both qualities that matter in Austin summers.

Why it matters in Austin

Older Austin homes — especially 1940s-1970s pier-and-beam construction — often have no ductwork or have ducts running through unconditioned crawl spaces that lose 25-30% of the conditioned air before it reaches the room. Mini-splits skip that whole problem.

They're also the right fit for additions, garage conversions, and ADUs (accessory dwelling units), which Austin homeowners build to add rental income or family space without extending the main system. A central AC pushed past its design capacity creates more problems than it solves; a dedicated mini-split is the cleaner answer.