Quick answer
- Mini-splits are ductless heat pumps: one outdoor unit, one or more indoor heads, no ductwork.
- They excel in additions, ADUs, garage conversions, and homes without existing ducts.
- Zone-by-zone control means you condition only the rooms you're using.
- For a whole large home with good existing ducts, a central system is usually still the cleaner answer.
What a mini-split is
A ductless mini-split is a heat pump without ducts. An outdoor compressor connects by a small refrigerant line set to one or more wall- or ceiling-mounted indoor heads, each conditioning its own zone with its own thermostat. Because there are no ducts, there are no duct losses — the efficiency a mini-split is rated at is close to the efficiency you get.
Where ductless wins outright
- ADUs, additions, and garage conversions — conditioning the new space without touching the main system's sizing.
- Older Central Coast homes with no ductwork (or asbestos-era ducts better left sealed).
- The one problem room: a west-facing bonus room over the garage that the central system never conquers.
- Homes where zoning matters: condition the bedroom wing at night, the living wing by day.
- Wine rooms, workshops, and detached offices needing independent temperature control.
Where central still wins
- Whole-home conditioning in a larger house with sound existing ducts — one system, one filter, invisible delivery.
- Aesthetics: some homeowners simply don't want visible wall units in every room.
- Deep filtration and IAQ add-ons integrate more naturally into a single central air handler.
Sizing and placement still decide everything
Mini-splits are unforgiving of oversizing — an oversized head short cycles, dehumidifies poorly, and hunts. Each zone needs its own load calculation, and head placement (airflow path, not just wall availability) determines whether the room actually feels even. This is installation-craft territory, which is exactly where detailed, clean workmanship pays off.
When you're ready