Ductless Heating & A/C

What a ductless mini split actually is

A ductless mini split is a heat pump split into two pieces: an outdoor compressor unit and one or more indoor units mounted inside the rooms you want conditioned. Instead of pushing air through ducts, refrigerant runs between the two through a small line set, usually passing through a three-inch hole in the wall. The indoor unit handles the air right there in the room.

Because it is a heat pump, it both cools and heats. One system covers the whole year in this climate, which is why ductless is often the simplest answer for a room that has neither. The compressors are inverter driven, meaning they modulate their speed rather than cycling hard on and off. In practice that means the room holds a steady temperature and the equipment is quiet, both outside and in.

The other advantage is that there are no ducts to leak. A duct system in an unconditioned attic loses a meaningful share of its conditioned air before it reaches a register. Ductless skips that loss. Each indoor unit also has its own control, so you condition the rooms you are using rather than the whole house.

When ductless is the right answer

Ductless makes the most sense where running ductwork would be expensive, disruptive, or physically impossible. The usual cases:

• A garage conversion, ADU, or addition with no duct capacity to spare
• A house with radiant floor heat, wall furnaces, or baseboards, and no duct system at all
• One or two rooms that are always too hot or too cold while the rest of the house is fine
• A finished attic, sunroom, or bonus room the existing system cannot reach
• A home office, workshop, or nursery that needs different temperatures from the rest of the house
• An older home where adding ducts would mean losing closet space or dropping ceilings
• You want to replace gas heat with electric without tearing the house apart

Ductless is not always the right call. If your house already has sound ductwork and a failing system, a conventional A/C installation or heating system installation is usually the better value. If the ducts are the problem, sometimes duct repair and sealing fixes the comfort complaint for far less. We will tell you which situation you are in.

How we plan and install a ductless system

Ductless installs live or die on placement and sizing, so most of the work happens before anything is mounted:

• 1. Room-by-room assessment. We calculate the load for each space you want conditioned rather than the house as a whole, because that is how a zoned system is sized. Oversized heads short cycle and never settle.
• 2. Placement and routing. We work out where each indoor unit goes for good air throw, where the outdoor unit sits for service access and noise, how the line set routes, and how condensate drains. Gravity drainage if we can, a pump if the room demands it.
• 3. Electrical and permit. Ductless needs a dedicated circuit and a disconnect. We check panel capacity, plan the circuit, and pull the permit with your city.
• 4. Installation. Mounting plates, wall penetration cored and sealed, line set run and brazed or flared to spec, outdoor unit set on a pad or wall bracket, electrical terminated, then the system evacuated to a deep vacuum and held.
• 5. Commissioning and handover. We verify charge, check operation in both heating and cooling, confirm airflow and drainage, then show you the controls and how to clean the filters.

System types and configurations

The main choice is how many rooms you are conditioning and what the indoor units should look like. Everything else follows from that.

Single-zone systems pair one outdoor unit with one indoor unit. They are the most efficient arrangement per room and the simplest to service, and they suit a garage conversion, an addition, or one problem bedroom.

Multi-zone systems run several indoor units off one outdoor unit, each with its own control. That keeps the outside of the house tidy. The tradeoff is that every zone depends on one compressor, and sizing gets more demanding.

Indoor units come in several forms. High-wall units are the common and least expensive option. Floor-mounted consoles sit low on the wall and suit rooms with full-height windows or sloped ceilings. Ceiling cassettes recess into a ceiling and throw air in four directions. Slim ducted air handlers hide in a soffit or closet and feed two or three nearby rooms through short duct runs, which is how you get ductless efficiency without visible equipment.

New ductless equipment now ships with A2L refrigerants such as R-454B as R-410A is phased down, so a system installed today uses refrigerant that will still be serviceable years from now.

What shapes the cost of a ductless install

The number of zones drives the cost more than anything else, followed by the type of indoor unit and how hard the line set is to route. A single high-wall head on an exterior wall with the panel nearby is the low end of the work. Four ceiling cassettes across two floors is not.

Beyond zone count: the style of indoor unit, since cassettes and ducted air handlers cost more to buy and considerably more to install than wall units. Line set length and routing matter, and a run through a crawlspace, up a wall cavity, or along the exterior in a line-hide cover is more labor than a short direct penetration. Electrical is often the deciding factor, because a dedicated circuit is required and older panels sometimes have no room. Then there is wall construction, since coring stucco, brick or post-and-beam differs in difficulty, plus condensate handling, the outdoor mounting method, the efficiency tier and permit fees.

Ductless in Santa Clara County homes

This county has an unusual amount of housing that ductless was made for. Homes built between the 1950s and the 1970s often use radiant slab heating or wall furnaces, with no duct system anywhere in the structure. The Eichler tracts in San Jose, Sunnyvale, Palo Alto and Mountain View are the clearest example: flat roofs, no attic, post-and-beam ceilings, and nowhere to put a duct without visibly changing the house. Ductless solves that without a remodel.

The ADU boom is the other driver. California has made it far easier to build accessory dwelling units and garage conversions, and Santa Clara County homeowners have built a lot of them. Those spaces almost never have duct capacity to borrow from the main house, and a single-zone ductless heat pump is usually the cleanest way to condition them.

Climate works in favor of ductless here. Winters are mild enough that a heat pump carries the whole heating season without backup strip heat, and inland peaks in Morgan Hill and Gilroy are what sizing gets checked against. Cool nights mean a modulating inverter system spends most of its time at low speed, which is where it is most efficient.

Two local realities worth planning for. First, permits: ductless installations require mechanical and electrical permits and must meet Title 24. There is no duct leakage test, since there are no ducts, which removes a step ducted changeouts cannot avoid. Second, air quality. Wildfire smoke from August into October and heavy spring pollen from oak, olive and grass mean the washable filters in each indoor unit need rinsing more often than the manual suggests. A clogged head loses capacity quietly, and nobody notices until the room stops keeping up.

Why homeowners pick Premium Heat and Air

We are family-owned, we have over 30 years in the trade, and we are a proud Carrier dealer. Ductless rewards careful planning more than most HVAC work, because a head in the wrong place or a zone sized wrong is not something you fix later without patching a wall.

So we spend the time up front. We size per room. We walk the line set route with you before we core anything. We are honest when ductless is not the right tool, and we handle the rest of the house too, from A/C repair and heating repair to thermostat installation and thermostat repair on the ducted side of a mixed system.

Areas we serve

We install ductless heating and cooling throughout Santa Clara County from our shop at 1724 Junction Ave, Ste E in San Jose. Four of those markets have pages of their own: Morgan Hill, Gilroy, Los Gatos and Saratoga.

Beyond those, we cover San Jose, Los Altos, Los Altos Hills, Palo Alto, Cupertino, Campbell, Santa Clara, Mountain View, Sunnyvale, Milpitas, Monte Sereno and Stanford. Call (408) 612-6711 or tell us about the room and we will take a look.