Air Conditioner Installation

What an air conditioning installation actually involves


A real A/C installation is a system replacement, not a box swap. The outdoor condenser, the indoor evaporator coil, the line set, the electrical disconnect, the condensate drain, the thermostat and the ducts all have to work as one matched set. Change one piece and everything connected to it has to be checked against the new equipment.


The work starts before any tools come out, with a load calculation. We measure the house: square footage, ceiling height, window area and orientation, insulation, and where the ducts run. That tells us how much heat the house gains on a hot afternoon, and it decides the tonnage. It is the difference between a system that runs long, steady cycles and one that blasts cold air for eight minutes, shuts off, and leaves rooms clammy and uneven. Oversizing is the most common mistake in this trade, and it comes from matching the old nameplate instead of measuring the house.


From there the job is recovering the old refrigerant, removing the old equipment, setting the new condenser level on a solid pad, brazing and pressure-testing the line set, pulling a deep vacuum, wiring, weighing in the charge, commissioning, and closing the permit. Most single-family changeouts here take one to two days. Attic air handlers, tight crawlspaces and ductwork that needs repair add time.


Signs it is time to replace rather than repair


Replacement usually makes sense once the equipment is old enough that the next failure is a question of when, not if, or once one repair costs a meaningful share of a new system. Residential cooling equipment typically lasts 12 to 20 years here, and the last few are the expensive ones:


  • The system is 15 years or older and has needed more than one repair in the last two summers
  • It runs on R-22 refrigerant, which has not been produced or imported in the United States since 2020 and is now costly to source
  • The compressor has failed, or the evaporator coil is leaking, on equipment past its useful life
  • Some rooms sit several degrees warmer than others no matter where you set the thermostat
  • Summer electric bills climb year over year while the house feels no cooler
  • The unit short cycles, or you hear grinding or screeching at startup
  • The same refrigerant leak has been topped off more than once


If the system is under ten years old and the failure is a capacitor, a contactor or a condenser fan motor, A/C repair is almost always the better call. We will tell you plainly which of the two you are looking at.

How we handle an installation


Every install follows the same sequence, because skipping steps is how systems fail early.


  • 1. In-home assessment. We look at the existing equipment, the ducts, the electrical panel, the access and the return air, then run the load calculation. If the ducts are the real problem, we say so before you spend money on a condenser.


  • 2. Written proposal. Equipment options in writing, tradeoffs explained. No pressure toward the largest system on the list.


  • 3. Permit and scheduling. We pull the mechanical permit with your city and schedule around your household.


  • 4. Installation. Old equipment out, refrigerant recovered to code, new equipment set, line set brazed under a nitrogen purge, system evacuated to a deep vacuum, electrical and condensate connected, thermostat installed and configured.


  • 5. Commissioning. We verify airflow, measure the charge by superheat or subcooling, check the temperature split across the coil and confirm static pressure. Those numbers separate a working install from a merely running one.


  • 6. Inspection and walkthrough. HERS verification where Title 24 requires it, final inspection, then we show you the filter, the drain and the shutoff.


Your equipment options


There are three practical choices for most South Bay homes: a straight air conditioner, a heat pump, or a ductless system. Which one fits depends on your heat source, your ductwork and your electrical service.


Single-stage air conditioners run at one speed. They are simplest and least expensive to install, and they suit smaller homes with sound ducts. Two-stage equipment runs low most of the time and steps up on the hottest afternoons, which evens out rooms and cuts noise. Variable-speed inverter systems modulate continuously and hold temperature in a tight band. They cost more up front and use less energy per hour of cooling.


Heat pumps cool the same way and reverse in winter to heat the house. Our winters are mild enough that one covers nearly the whole heating season, and California's code increasingly favors them. If your furnace is also near the end of its life, replacing both at once beats two separate projects. We can weigh that against a standard heating system installation.


Ductless systems suit additions, converted garages and houses with no usable ducts.


Worth knowing before you shop: R-410A is being phased down, and new residential equipment now ships with A2L refrigerants such as R-454B. What you install today uses the refrigerant that will still be serviceable in fifteen years.

What affects the cost of a new system


Installation price is driven by system size, the condition of what it connects to, and how hard the equipment is to reach. Anyone who quotes you over the phone without seeing the house is guessing.


The main factors are the capacity your load calculation calls for, the efficiency tier, and whether you go single-stage, two-stage or variable-speed. After that comes ductwork, since leaky or undersized ducts have to be corrected or the new system will never reach its rated performance. Access matters: an air handler in a low-clearance attic is slower work than a closet unit. Electrical is a common surprise, because older homes on smaller panels sometimes need a circuit or service change, particularly for heat pumps. Then there is line set length, condensate routing, pad or platform work, the thermostat you choose, permit fees and HERS testing. If an existing furnace is staying, its blower has to match the new coil.


What Santa Clara County means for your installation


Cooling loads vary sharply across this county, and equipment should be sized for your part of it. Morgan Hill and Gilroy run hot, with summer afternoons in the 90s and stretches in the triple digits. San Jose sits cooler. Palo Alto, Mountain View and Los Altos catch enough bay influence that peak loads are lower. Nights cool off nearly everywhere, which is why an oversized system here feels worse than a correctly sized one.


Title 24 shapes what a legal changeout looks like. Replacement systems in existing homes generally require a permit, duct leakage testing and refrigerant charge verification by an independent HERS rater. A bid that leaves that out leaves you holding an unpermitted system when you sell. San Jose, Morgan Hill, Gilroy, Los Gatos and Saratoga each run their own building department. We handle that for you.


Air quality drives equipment choices here too. Wildfire smoke season runs roughly August into October, and on those days sealed ducts and real filtration are the difference between clean indoor air and a house full of haze. Spring brings oak, olive and grass pollen. Both argue for a filter cabinet that will take a MERV 13 filter without choking the blower.


Then there is the housing stock. Much of this county went up between the 1950s and the 1970s, with undersized returns and ducts run through unconditioned attics. In the Eichler tracts of San Jose, Sunnyvale and Palo Alto it means radiant slab floors and no ducts at all. Those houses need a different plan than a 2005 build.


Why homeowners choose Premium Heat and Air


We are family-owned, we have over 30 years in the trade, and we are a proud Carrier dealer.


What customers notice is that we measure. We calculate the load instead of matching the old nameplate. We verify the charge instead of setting it by feel. We tell you when a repair will do, and when it will not. If your ducts are the real problem, we would rather fix the ducts than sell you a bigger condenser that cannot breathe. The same approach runs through our heating repair and thermostat repair work.


Where we work


We install air conditioning across Santa Clara County from our shop at 1724 Junction Ave, Ste E in San Jose. Our closest markets have their own pages: Morgan Hill, Gilroy, Los Gatos and Saratoga.


We also serve San Jose, Los Altos, Los Altos Hills, Palo Alto, Cupertino, Campbell, Santa Clara, Mountain View, Sunnyvale, Milpitas, Monte Sereno and Stanford. For an in-home assessment, call (408) 612-6711 or get in touch.