Ductless Mini-Split Heat Pump
Installation in San Francisco
The right solution for San Francisco's Victorian and Edwardian homes, condominiums, and high-rises — where running ductwork is impossible, impractical, or simply unnecessary. Heat, cool, and dehumidify every room with precision, without tearing up your walls or ceilings.
Why Most San Francisco Homes Can't Use Conventional Ductwork
San Francisco's housing stock is unlike any other city in America. More than half of the homes in neighborhoods like the Mission, Castro, Noe Valley, the Richmond, and the Sunset were built between 1890 and 1940 — a period when central forced-air systems simply didn't exist. These Victorians and Edwardians were designed around gas floor furnaces, wall heaters, and radiators. There was never any intent to run ductwork, and the structural reality of these buildings makes retrofitting it genuinely difficult.
Victorian and Edwardian homes typically use balloon framing, where stud cavities run continuously from foundation to roof. This makes dropping flex duct through walls nearly impossible without major surgery. The walls themselves are finished in original plaster over wood lath — a beautiful material that cracks unpredictably when cut. Add shared party walls with zero setback to the neighbors, and in many cases, running a duct system would cost more than the heat pump itself and leave you with a home that looks like a construction site.
For these homes, ductless mini-split heat pumps aren't just a good option — they're often the only practical one. Installation requires nothing more than a 3-inch hole through the exterior wall for the refrigerant line set, a dedicated circuit, and a wall or ceiling mount for the indoor unit. No structural changes. No soffits. No dropped ceilings. A typical single-zone installation is complete in a single day.
Common SF home challenges we navigate every day:
No existing ductwork
The majority of pre-WWII SF homes were never built with ducts. Installing them now means opening walls, ceilings, and floors — invasive, expensive, and often impossible in multi-unit buildings.
Plaster walls and ceilings
Original plaster-over-lath is extraordinarily sensitive to vibration. Cutting it requires specialized oscillating tools, careful scoring, and experience — or you end up with cracks spreading across an entire room.
Non-standard framing
Older SF homes frequently have framing at irregular intervals — not the standard 16" or 24" on center you find in modern construction. This affects where ceiling cassettes and line sets can run, and requires experienced hands to work around.
High-rise and condo installations
We work in SF high-rise buildings routinely — from SOMA condos to Pacific Heights apartment buildings. Outdoor units mount to exterior wall brackets or balconies; no rooftop access required for most units.
Ceiling Cassette Installations: An SF Specialty
Ceiling cassettes are the preferred choice for open living areas, kitchens, and spaces where wall-mounted units would feel intrusive. But in San Francisco's older homes, they require a level of expertise that most contractors simply don't have.
A ceiling cassette unit sits flush with the ceiling surface, drawing return air from the center and distributing conditioned air in four directions through adjustable louvers. In a large open Victorian flat, one well-placed cassette can condition an entire living/dining/kitchen area quietly and evenly — no bulky wall unit dominating the room.
The challenge in San Francisco is that cassette installation requires cutting a precise opening in the ceiling and then hanging the unit from the structural framing above. In modern homes with drywall and standard 16-inch framing, this is straightforward. In SF's pre-war homes, it's a different story:
- Beam spacing is frequently irregular — sometimes 12 inches, sometimes 20, sometimes a mix within the same room. We locate every framing member with professional-grade stud finders and probes before making any mark.
- Plaster ceilings crack from vibration, not just from cutting. We score the perimeter with an oscillating tool before any opening is made, and brace the surrounding field to absorb vibration.
- Access to the plenum space above varies wildly — some SF homes have a walkable attic, others have only inches of clearance. We assess this during our site visit and plan the installation method accordingly.
- Condensate drainage must be planned carefully in a multi-story building. We route drain lines to appropriate termination points without compromising adjacent units or building systems.
Mini-Split System Options
Single-Zone Wall Unit
One outdoor unit, one indoor unit. Perfect for a bedroom, home office, or studio. Fast installation, lowest cost. Ideal for older SF homes adding climate control to a specific room.
Multi-Zone Wall Units
2–5 indoor units on one outdoor unit. Heat or cool each room independently. Common in SF flats where each room needs separate temperature control.
Ceiling Cassette (Single Zone)
Flush-mount ceiling unit for open living areas. Distributes air in four directions. Requires ceiling access; our SF plaster expertise is critical.
Multi-Zone Mixed System
Combination of wall units and cassettes on one outdoor unit. Best for whole-home conditioning in larger SF homes and flats.
We Work in SF High-Rise Buildings
San Francisco has thousands of condominium and apartment units in mid-rise and high-rise buildings — SOMA, Mission Bay, Rincon Hill, Fisherman's Wharf, the Marina, Pacific Heights. These units often rely on PTAC units (the through-wall hotel-style systems) or window units that are loud, inefficient, and unsatisfying.
Mini-split heat pumps are the gold-standard upgrade for high-rise units. The outdoor unit can be mounted on a balcony railing bracket, a dedicated exterior wall bracket, or a rooftop terrace — without any building-wide infrastructure changes. We coordinate with HOA requirements and SF DBI for permit compliance, and our crews are experienced with the logistics of working in occupied high-rise buildings.
We've installed mini-splits on floors from the 2nd to the 40th. Each installation is engineered for the specific unit layout, exposure, and building rules. Our clients in high-rise condos consistently report that the switch from PTAC to mini-split is one of the most noticeable quality-of-life improvements they've made in their home.
Our Installation Process
Free Home Assessment
We visit your home, assess the space, identify ideal unit locations, plan the refrigerant line route, and evaluate electrical capacity. For ceiling cassette work, we locate all framing.
System Design & Permitting
We calculate the correct capacity using Manual J methodology, select the right system, and file for the SF mechanical permit. We handle all DBI communications.
Precision Installation
Our crew mounts the indoor and outdoor units, runs the refrigerant line set through the 3-inch exterior wall penetration, wires the dedicated circuit, and connects the condensate drain.
Commissioning & Testing
We vacuum the refrigerant lines, charge the system, test every operating mode, verify airflow and temperatures, and walk you through using your new system's controls and app.
Permit Sign-Off
We schedule and pass the SF DBI final inspection, provide you with all paperwork, and register your warranty with the manufacturer.
Mini-Split Installation FAQ
Ready to Ditch Your Wall Heaters for Good?
Get a free in-home assessment and quote. We'll measure your space, explain your options, and give you a firm price — no pressure, no surprises.