# AC Repair in Los Altos Hills, CA

- Link: https://www.air.systems/our-hvac-service-areas/hvac-repair-los-altos-hills/ac-repair-in-los-altos-hills/
- Published: 2026-08-31T15:53:37-07:00
- Author: John Towner

# 󠀁[AC Repair in Los Altos Hills](https://www.air.systems/our-hvac-service-areas/hvac-repair-los-altos-hills/)󠁿, CA

If the air conditioning quit in Los Altos Hills, here is the short version. On cooling
equipment the size of what goes into these houses, the three complaints are one 
warm wing, ice on the indoor coil, and a system that runs all afternoon without 
ever satisfying the thermostat. They usually share a cause, that cause is usually
air rather than refrigerant, and none of the three means the compressor is finished.

I am John Towner. I own Silicon Valley Comfort, twenty five years in the trade, 
and I drive the truck myself. 408-691-5940 rings my phone directly, any hour, any
day.

## Why 󠀁[AC repair in Los Altos Hills](https://www.air.systems/our-hvac-service-areas/hvac-repair-los-altos-hills/)󠁿 is its own job

Start with my own records rather than a description of the town, because the records
here point somewhere unusual.

Every Los Altos Hills system where I have the refrigerant written down is on R-410A.
Not one R-22 machine. That is not what the rest of my route looks like. In Los Gatos,
Santa Clara and San Carlos I am still opening cabinets full of R-22, and on those
the repair or replace conversation is half about the refrigerant itself: production
ended in 2020, what is left is scarce, and a leak in an R-22 system is often the
end of the system rather than the start of a repair.

In this town that fork does not exist. Whatever is wrong with your air conditioner
here, what is in it is still made, still available, and not a reason to condemn 
the equipment.

The second thing my file says is size. The cooling equipment on file here runs four
to five and a half tons, the largest band anywhere on my route, and that number 
is really a statement about air. A five ton coil wants somewhere near two thousand
cubic feet a minute crossing it before it will hold a decent [temperature split](https://www.air.systems/ac-delta-t-test/).
That is a great deal of air to ask a duct system for, and in a house where a panel
can close most of that duct off at will, it is air the coil often does not get.

Put the two together and you have my starting position on a cooling call in this
town. The refrigerant is not obsolete and the equipment is not junk. The question
is whether the air is moving.

### What actually fails on a Los Altos Hills AC

I am not going to list every part that can fail. Here is what actually comes up 
on equipment this size.

Start with the cheap electrical failures, because they are cheap and because you
should not be paying for anything bigger until they are ruled out. A run capacitor
drifts out of tolerance, or a contactor burns and pits its points, and the condenser
will not start. It hums, or the fan turns if you push it and not on its own. Do 
not push it. Both of those parts carry the starting current of a four to five and
a half ton machine every time it cycles, which is more current than the same parts
see on a small system, and both take a meter and a few minutes to settle.

The failure that belongs to houses like these is the indoor coil icing over. A coil
that size needs a lot of air across it to work at all. Close the zones down to a
bedroom wing overnight, add a filter nobody has changed, and the coil runs cold 
enough to grow ice. Cooling stops, somebody sees frost on the copper, and the words
refrigerant leak get said out loud. That is how an airflow problem gets sold as 
a refrigerant problem. Sometimes it really is a leak. Often it is the filter, the
coil and a zone panel doing exactly what it was told to do.

Right behind it is the condensate side. A coil that size makes a lot of water, and
the drain line usually runs a long way from wherever the air handler sits to wherever
it discharges. Any sag holds water, anything growing in it plugs the trap, and when
the pan fills the float switch shuts the system off. Nothing looks broken. The air
conditioner is fine and the drain is not.

Real leaks I chase and prove, rather than quietly adding refrigerant and driving
away.

### Glass, Sun, And Hillside Exposure

Homes in Los Altos Hills are built for the view, which means big west and south 
facing glass on open hillsides with little shade. On a hot afternoon, those rooms
gain heat faster than any other part of the house. When the family room overheats
while the rest of the house is fine, the air conditioner is often doing exactly 
what it was sized to do. It was just sized for the whole house, not that one room
of glass.

Good AC repair in Los Altos Hills starts by separating equipment problems from load
problems. Measuring the charge, airflow, and [temperature split](https://www.air.systems/ac-delta-t-test/)
tells us whether the system is healthy. If it is, the fix for the hot room may be
more supply air, a dedicated zone, a ductless head, or window treatment, not a bigger
condenser.

 ⌊Air conditioner condenser on a pad with refrigerant lines routed to the house,
typical of AC repair in Los Altos Hills⌉ ⌊Condenser with refrigerant hoses connected
to the service ports during a charge check⌉

Left: a condenser with its line set routed back to the house. Right: a charge check
on the service ports. Long runs get weighed in and confirmed, not guessed.

### Long Line Sets And Remote Condensers

On large lots, condensers often sit far from the house to keep them quiet and out
of the view. Long refrigerant lines need extra refrigerant weighed in beyond the
factory charge, and the charge has to be confirmed with superheat or subcooling.
A system charged by feel on a long run is the most common reason a hillside system
never quite cools the far end of the house.

Those long runs also cross open ground where rodents chew foam insulation off the
suction line. Bare copper sweats, drips, and loses capacity. We check the whole 
run, not just where it enters the house.

### Generators And Soft Starts

Many homes up here run backup generators. An air conditioner compressor pulls a 
big surge of current when it starts, and on generator power that surge can stall
the compressor or trip the generator. A soft start kit reduces that surge and lets
a properly sized generator carry the cooling. If the air conditioner trips the generator
every time the power goes out, that is the first thing to look at. Filters matter
for these systems too, and the [MERV rating](https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating)
should match what the blower can handle, especially during smoke season.

Before the hot season, a spring check covers the outdoor coil, the electrical, the
start components, and the charge, with readings saved for next time. On a property
with several systems, each one gets its own record so a failure on one never turns
into guesswork about the others.

Clear brush and dry grass back from each outdoor unit, too. It helps airflow and
it matters in fire season.

 ⌊Electrical connections inspected inside an outdoor AC unit⌉ ⌊Digital refrigerant
scale and manifold gauges⌉

Left: electrical connections and the contactor checked. Right: a scale and digital
gauges. Generator problems often start with the compressor start circuit.

When you book, tell us which building and which system is not cooling, and where
the condenser sits on the property. On a large lot, outdoor units can be a long 
walk from the house, and knowing the layout ahead of time keeps the visit efficient.
If the system trips a generator or a breaker every time it starts, mention that 
too, since it points at the start circuit.

### How I diagnose it

Every call starts with meters, not a brochure. On a zoned house I take three readings,
in this order.

Static pressure across the air handler comes first, and I take it with the zones
set the way your house actually runs, not with every damper propped open to flatter
the number. Total external static against what the blower is rated for tells me 
whether this machine can move its rated air at all. If it cannot, no part I change
will fix your complaint, and you need to hear that before you buy anything.

Temperature split across the evaporator is second. Supply air against return air,
compared with what that coil should be doing in the conditions of the day, and next
to the static number it says whether the indoor half is moving air.

Superheat and subcooling against the charging chart for your model is third, read
in front of you rather than from memory. It is the only honest way to say whether
the charge is right, and on a long line set the correct charge is not simply the
number on the sticker, because the line itself holds refrigerant. If the condenser
will not start at all I begin instead with capacitor microfarads against the rating
printed on the can. Three readings, not seven, and I write them down and leave them
with you.

### Repair or replace

My honest position, and it costs me work to say it: in this town, fix it. The reason
is the refrigerant.

On most of my route the strongest argument anybody has for replacing a repairable
air conditioner is that it is full of R-22. That argument is often fair. Production
ended, the price of what remains keeps climbing, and putting a large charge back
into a system that has already proved it leaks is money you may not see again. Take
a look at my Los Altos Hills file and that argument is simply not available.

Everything here that I have the refrigerant recorded for is R-410A. Remove the refrigerant
case and what is left of the usual replacement pitch is a list of parts: a capacitor,
a contactor, a fan motor, a plugged drain, a coil that needs cleaning. Those are
repairs, and they are the right call.

There is a second pitch to watch for in houses this size. The far wing never gets
cold, so the system must be too small, so you need more tons. If the run to that
wing is long and static pressure is already high, a bigger condenser makes it worse.
It satisfies the thermostat faster, shuts off sooner, and gives the far end of the
duct even less time to receive air. Four tons and up is already the large end of
residential. The fix for one warm wing usually lives in the duct and the zone panel,
and that is less work than a new system.

Replacement is honestly right when the compressor is dead, when there is a leak 
you would have to chase through a line set buried under a driveway or a slab, or
when the same system has failed three times in two seasons with a different dead
part each time. I will tell you when I think you are there, on the first visit, 
rather than sell you a repair that buys one summer.

## Los Altos Hills neighborhoods I cover

Los Altos Hills changes more from one property to the next than it does from one
part of town to another. Off the Page Mill corridor, up in Fremont Hills, the lots
run to an acre and more with real grade across them, and the outdoor unit ended 
up wherever it could go rather than wherever would have been convenient.

If yours sits well away from the house, behind a garage or down a slope, that buys
you quiet and it costs you line set. A longer line holds more refrigerant and gives
you more places to lose it, and where there is rise between the outdoor unit and
the indoor coil, the vertical run is part of how oil finds its way back to the compressor.
So before anyone charges your system by feel, line length and lift belong in the
number.

The other thing I ask on the phone is how many outdoor units you have. The one that
is not cooling is not always the one you are standing next to.

## Straight Pricing, No Surprises

### Residential Diagnostic

$99

Standard hours. After 6:00 PM, Saturdays, and holidays: $149. The standard diagnostic
is credited toward your repair if you approve the work on the same visit.

### Commercial Diagnostic

$199

Business hours. After-hours: $299. Light commercial, retail, and multi-family equipment.

### Repairs and Installations

Quoted before we touch a wrench. Supplier invoice attached to your job sheet.

## AC Repair Los Altos Hills: common questions

### The bedroom wing never gets cold. Do I need a bigger air conditioner?

Usually not. In a zoned house a wing that never gets cold is nearly always duct 
and airflow: a long run losing capacity, a damper that is not opening, or static
pressure so high the blower cannot deliver its rated air. Adding tons makes short
cycling worse and gives the far end of the run even less time to fill.

### There is ice on the copper line at the indoor unit. Does that mean a refrigerant leak?

It might, and it might be air. Ice forms with a low charge or with too little air
crossing the coil, and a loaded filter or a closed off zone will do it easily on
a system this size. Switch to fan only and let it thaw completely, because nobody
can read a charge through ice. Then change the filter.

### The system shut itself off and there is water near the air handler. What happened?

That is the condensate side rather than the cooling side. A float switch in the 
drain pan or the line is cutting the system off before water reaches your ceiling.
The repair is clearing the trap and the line and finding the sag behind it. Do not
bypass that switch to get cooling back tonight, particularly where the air handler
sits over finished space.

### Somebody told me my refrigerant is obsolete and the system should be replaced. Is that right here?

Check the data plate before you believe it. Every Los Altos Hills system I have 
the refrigerant recorded for is R-410A, which is still made and still available,
so in this town that pitch usually does not survive a look at the label. If yours
does turn out to be R-22, the conversation is different and I will walk you through
it honestly.

### Do you work on Bryant equipment?

Yes, and Bryant comes up in my Los Altos Hills records more than any other name.
The other brands too. What matters more than the badge on the cabinet is whether
the outdoor unit and the indoor coil are a matched set, because the charging chart
only means something if they are.

### It is a hot afternoon and nothing is cooling. Do you actually pick up?

Start with what I cannot do, because I am one person. I will not hand you an arrival
window that I might not hold. If I am under a house across the county I will say
so. What you do get is 408-691-5940 ringing me at any hour, seven days a week, and
no answering service between you and me.

## Related pages

 * [All HVAC service in Los Altos Hills](https://www.air.systems/our-hvac-service-areas/hvac-repair-los-altos-hills/)
 * [Furnace Repair in Los Altos Hills](https://www.air.systems/our-hvac-service-areas/hvac-repair-los-altos-hills/furnace-repair-in-los-altos-hills/)
 * [Heat Pump Repair in Los Altos Hills](https://www.air.systems/our-hvac-service-areas/hvac-repair-los-altos-hills/heat-pump-repair-in-los-altos-hills/)
 * [AC Repair in Santa Clara](https://www.air.systems/our-hvac-service-areas/hvac-repair-in-santa-clara/ac-repair-in-santa-clara/)
 * [AC Repair in Saratoga](https://www.air.systems/our-hvac-service-areas/hvac-repair-in-saratoga/)
 * [AC Repair in Sunnyvale](https://www.air.systems/our-hvac-service-areas/hvac-repair-in-sunnyvale/ac-repair-in-sunnyvale/)
 * [AC Repair across the South Bay](https://www.air.systems/air-conditioning-services/)
 * [HVAC service across Santa Clara County](https://www.air.systems/our-hvac-service-areas/santa-clara-county/)
 * [24/7 emergency HVAC repair](https://www.air.systems/hvac-services-in-san-jose/emergency-hvac-repair-in-san-jose/)