Ductless Mini-Splits for Palo Alto homes without ducts

A ductless mini-split is a heat pump with an outdoor unit connected to one or more indoor heads by a small refrigerant line. In Palo Alto it is the go-to option for Eichlers with radiant floors, room additions, ADUs and older homes without ductwork. Each zone has its own thermostat, so you heat or cool only the rooms you use.

Where ductless makes the most sense

• Eichler and mid-century homes in Greenmeadow, Fairmeadow and other tracts, where radiant floors handle heat but there is no duct system for cooling
• Additions and converted garages that the original system was never sized to reach
• ADUs and backyard cottages, which need their own independent system
• Upstairs bedrooms and home offices that run hot every afternoon
• Older homes in Professorville or Old Palo Alto where adding ducts would mean opening plaster walls

Indoor unit styles

Wall-mounted heads are the most common and the most affordable. Ceiling cassettes sit flush in the ceiling and spread air in four directions, a nice fit for open living spaces. Slim ducted air handlers hide in an attic or soffit and feed two or three rooms through short duct runs, so you don’t see equipment on the wall at all. Floor consoles work under windows and in rooms with low walls.

Designing a multi-zone system

A single outdoor unit can serve several indoor heads, but bigger isn’t always better. Multi-zone outdoor units run less efficiently when only one small room is calling for heat. For some homes, two single-zone systems beat one five-zone system. We size each zone with a load calculation and design line set routes that are clean on the outside of the house, especially on Eichlers, where exposed line sets on beautiful siding are a real concern.

Rebates and permits

A ductless heat pump that replaces a gas heater can qualify for the City of Palo Alto Utilities Heat Pump HVAC rebate. The Rebate Hub doesn’t list mini-splits separately, so we confirm eligibility with CPAU for your specific project. Qualifying installs can use the City’s instant permit for residential heat pumps. See the CPAU rebate guide.

Maintenance

Mini-splits need clean filters (every month or two in heavy use), a yearly coil and blower wheel cleaning, and a clear condensate path. Dirty blower wheels are the most common cause of musty smells and weak airflow. We include mini-splits in our maintenance plans.