A ductless mini-split pairs an outdoor unit with one or more indoor units on a wall or ceiling, linked by a refrigerant line set, a drain and a control cable through a small opening. In Sunnyvale, Santa Clara and Cupertino it is the usual answer for homes without ducts, room additions, converted garages and upstairs rooms that a central system never cooled well. Each indoor unit has its own setting, so you cool only the rooms you use.
Why Eichler homes often go ductless
Eichlers, best known in Sunnyvale and Cupertino, are heated by radiant tubing in the concrete slab and have flat or low-slope roofs with no attic. There is no space to run ducts, so central air is impractical without major construction. Wall-mounted mini-splits add cooling while the radiant floor keeps doing the heating. The line sets usually run along an outside wall inside a cover, and indoor units sit high on interior walls where they can blow across the main living space. For the heating side, see radiant floor heating and the pros and cons of radiant heat.
Single-zone or multi-zone
A single-zone system has one outdoor unit for one indoor unit: simple, and a fault affects only that room. A multi-zone system runs several indoor units from one outdoor unit, which means less equipment outside, but every zone depends on that one unit. Each indoor unit should be sized for its own room; an oversized unit in a small bedroom short-cycles and leaves the air clammy.
Indoor unit styles include high-wall units (the most common), ceiling cassettes, floor consoles and slim ducted units hidden in a soffit or closet.
Heating with a ductless heat pump
Most mini-splits are heat pumps, so the same equipment heats in winter, and our mild winters suit them. Ductless heat pumps can take over the heating in an addition or back up an aging radiant system. For whole-house options, compare heat pump installation.
Installation: getting the placement right
The decisions that matter most in a mini-split installation:
- Indoor unit position — high enough to throw air across the room, not aimed straight at a bed or desk, with room around it for airflow and filter access.
- Outdoor unit — on a pad or wall bracket, with clearance for airflow and service, away from bedroom windows.
- Line set route — short and tidy, covered outdoors; long runs are checked against the manufacturer’s limits.
- Condensate — drained by gravity where possible, with a small pump where it is not.
- Electrical — a dedicated circuit from the panel.
The lines are pressure-tested and evacuated before refrigerant is released into them, just as on a central system.
Repair: common ductless problems
| What you notice | Likely cause |
|---|---|
| Indoor unit blinking or showing an error code | Sensor, communication or board fault; the code narrows it down |
| Water dripping from the indoor unit | Clogged drain line, kinked hose or failed condensate pump |
| Weak airflow or a musty smell | Dirty filters, coil or blower wheel |
| One room not cooling while the others are fine | A fault at that indoor unit or its line set |
| Outdoor unit will not start | Power supply, control board or inverter fault |
More detail is on the mini-split repair page.
Maintenance
Washable filters in each indoor unit clog quickly during heavy use, so check them at least monthly. The coil and the drum-shaped blower wheel collect dust and growth that cut airflow and cause odors; they need a professional cleaning, which is part of ductless maintenance.
Brands we work on
We install, repair and maintain mini-splits from Mitsubishi, Fujitsu, Daikin, LG and other common makers, in single-zone and multi-zone setups. We are independent, and replacement parts are matched to the exact model and its warranty status.
What shapes the scope
The number of zones, the indoor unit type, the line-set length and route, your panel capacity and the wall construction. You get the findings and the cost factors before any work begins. Our article on ductless mini-split benefits helps if you are still deciding, and larger buildings with many zones are covered under VRF/VRV systems. City pages: Sunnyvale, Santa Clara, Cupertino.