AC not cooling
Running, but the housekeeps getting hotter.
Start with the five checks below. They take about ten minutes, they are all safe to do yourself, and they resolve a fair number of these calls without anyone coming out. If none of them fixes it, the causes are further down.
Five checks before you call anyone
All safe, all free, none require opening anything electrical. Work through them in order — they are arranged by how often they turn out to be the answer.
1
Set the thermostat fan to AUTO, not ON
Check the fan setting on your thermostat. If it is set to ON, change it to AUTO and give the system fifteen minutes.
Why this is first: with the fan on ON, the blower runs continuously even when the compressor is not cooling. Between cooling cycles you get room-temperature air blowing out of the vents, which feels exactly like a broken air conditioner. This is one of the most common calls we get that is not a fault at all. Also confirm the mode is set to COOL and the target temperature is several degrees below the current room reading.
2
Pull the air filter out and look at it
Find the filter, slide it out, hold it up to a light. If you cannot see light through it, replace it. If you do not have a spare, run the system without one only long enough to get through the evening, then fit a new one.
Why it matters: a blocked filter starves airflow across the evaporator coil. Reduced airflow means reduced cooling, and if it goes on long enough the coil freezes and you get no cooling at all. In Fresno's dust and pollen, filters load up faster than the packaging suggests. More on filters.
3
Look for ice on the refrigerant lines
Go to the outdoor unit and look at the two copper lines. If either has visible ice or frost on it, or the indoor coil is iced up, turn cooling OFF at the thermostat and set the fan to ON. Leave it that way for several hours.
Why this matters more than it looks: running an iced-up system can send liquid refrigerant back to the compressor, which causes expensive mechanical damage. Setting the fan to ON thaws the coil without running the compressor. Freezing is always a symptom of something else, usually restricted airflow or low refrigerant, so it needs diagnosing once thawed. More on frozen coils.
4
Check both breakers, and check whether the outdoor unit is running
Look at your main panel for a tripped breaker, and check the disconnect box on the wall beside the outdoor unit. Then go outside and confirm the condenser is actually running and the fan on top is spinning.
What it tells you: a system where the indoor blower runs but the outdoor unit is silent has an electrical or control fault rather than a refrigerant problem. If the outdoor fan is not spinning while the compressor is running, switch the whole system off immediately — that combination overheats and damages compressors within minutes. A breaker can be reset once. If it trips again, stop and call.
5
Look at the outdoor coil, and clear around it
Walk around the outdoor unit. Clear away leaves, grass clippings, cottonwood and anything stacked against it, and give it at least two feet of clear space on all sides. Look through the fins — if you can see a solid mat of dust and debris, that is your problem or part of it.
Why it matters in Fresno: the outdoor coil rejects your home's heat into the outside air. Valley dust and agricultural particulate pack those fins faster here than almost anywhere in the country. A loaded coil raises operating pressure, cuts cooling capacity, drives up the electric bill and eventually damages the compressor. Do not pressure-wash it — the fins bend easily and that makes it worse.
None of that worked? Then it is something that needs a meter on it. The likely causes are below, with what each one generally costs to put right.
What it usually turns out to be
Ordered roughly by how often we find each one on a no-cooling call in Fresno. Costs are typical local ranges, not quotes.
A failed run capacitor
$150 – $350The single most common failure we see, and the cheapest to fix. The capacitor stores the charge that starts your compressor and fan. When it drifts out of tolerance the system hums, struggles or refuses to start. It is one reading in microfarads to confirm. More on capacitors.
A dirty condenser coil
MaintenanceExtremely common here. Once the fins are packed with valley dust, the system cannot dump heat outside and cooling capacity drops even though everything is running normally. Cleaned properly during a tune-up, and it pays for itself in reduced running cost. What a tune-up covers.
Low refrigerant from a leak
$400 – $1,600Refrigerant is never consumed, so a system that is low has a leak somewhere. The cooling drops off gradually over weeks, and the compressor runs hot and starved the whole time. Adding refrigerant without locating the leak is not a repair. More on leak detection.
A pitted or failed contactor
$150 – $300The switch that feeds power to the outdoor unit. Its contacts erode with every cycle, and burned contacts starve the compressor of the voltage it needs to start. Produces intermittent faults that look mysterious until somebody measures the voltage drop across them.
A frozen evaporator coil
Depends on causeIce on the indoor coil blocks airflow completely, so nothing cold reaches the house. The freeze itself is easy to clear. The cause behind it — restricted airflow or low refrigerant — is what actually needs fixing, and the two are different repairs at different prices.
A seized condenser fan motor
$400 – $800If the outdoor fan is not turning, heat has nowhere to go and the system shuts down on high pressure within minutes. Worth noting that a fan not spinning is often the capacitor rather than the motor, and the difference in price is substantial. More on fan motors.
Duct leakage into the attic
VariesThe equipment is fine and the cold air never arrives. Fresno attics reach well over 150 degrees in summer, so ducts leaking up there lose a meaningful share of your cooling before it reaches a room. This is a common cause of a system that has "never really cooled well" rather than one that failed suddenly.
A failing compressor
$1,800 – $3,500The expensive answer, and the least common on this list. Before accepting it, insist the capacitor and contactor were measured, because both produce identical symptoms at a fraction of the cost. More on compressors.
Several of these produce identical symptoms from the driveway, which is why they get measured rather than guessed. See exactly what we measure and why.
Worth ruling out
Is it actually broken, or is it 108 degrees outside?
Air conditioning systems are sized against a design temperature, which represents a hot day rather than the hottest day on record. That is deliberate — sizing for an extreme outlier would produce an oversized system that behaves badly for the other 360 days of the year.
So on a genuinely extreme Fresno afternoon, a healthy correctly-sized system runs continuously and may sit a few degrees above setpoint. That is the design working as intended, not a fault, and it is a very common reason people are told they need a bigger system when they do not.
Telling the difference
- Probably normal: it holds temperature fine most days and only drifts on the worst afternoons, then catches up in the evening.
- Probably normal: the air from the vents is clearly cold, the house is just not winning against the outdoor temperature.
- Not normal: the air coming out is not noticeably cold at all, at any time of day.
- Not normal: it used to keep up on days like this and no longer does. Something has changed.
- Not normal: the indoor temperature climbs steadily even overnight when it is cool outside.
Five things not to do
All of these are common, all of them feel sensible, and all of them make the situation worse.
-
Do not keep resetting a breaker that trips again
The breaker is doing its job. Something is drawing more current than it should, and repeatedly forcing power back into that fault risks damaging the compressor and creates a genuine fire risk. Reset it once. If it goes again, leave it off and call.
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Do not run the system while it is frozen
Ice on the coil means liquid refrigerant can return to the compressor, and compressors are designed to pump gas. This is one of the fastest ways to turn a moderate repair into a very expensive one.
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Do not set the thermostat to 60 to cool the house faster
A thermostat is a target, not a throttle. Your system removes heat at exactly the same rate whether it is set to 72 or 60. All this achieves is a system that runs past the point you would have been comfortable, on a day when it is already struggling.
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Do not close vents in rooms you are not using
It feels efficient and it is not. Closing registers raises static pressure across the whole duct system, which reduces airflow, strains the blower and can freeze the coil. Duct systems are balanced as a whole, not room by room.
-
Do not buy refrigerant and add it yourself
Handling refrigerant legally requires EPA certification, overcharging a system damages it as surely as undercharging, and if it is low then there is a leak that adding more will not fix. This is genuinely not a homeowner job.
Stop and call now if any of this applies
These are not wait-until-Monday situations.
- A burning or electrical smell from any part of the system
- The breaker trips again after a single reset
- Loud grinding, screeching or banging from the outdoor unit
- Water actively leaking from the air handler or through a ceiling
- The indoor temperature is climbing with infants or elderly people at home
- The outdoor fan is stopped while the compressor is still running
Common questions
Why is my AC running but not cooling the house?
The most common causes are a failed run capacitor, a condenser coil packed with dust, low refrigerant from a leak, a pitted contactor, a frozen evaporator coil, a seized condenser fan motor or duct leakage into a hot attic. Several of these produce identical symptoms from outside, so they are separated by measuring superheat, subcooling, static pressure, capacitance and amp draw rather than by guessing.
Why is my AC blowing air that is not cold?
First check whether the thermostat fan is set to ON rather than AUTO. On ON, the blower runs continuously even between cooling cycles, so room-temperature air comes out of the vents and feels like a failure. If it is already on AUTO, the likely causes are a failed capacitor, low refrigerant, a frozen coil or an outdoor unit that is not running at all.
How cold should the air from my vents be?
A healthy system typically produces a 16 to 22 degree difference between the return air and the supply air, and in Fresno's dry summer air that split often runs higher. What matters more than the absolute number is whether the air is clearly cold to the hand and whether the split has changed from what the system used to do.
Can a dirty air filter really stop my AC from cooling?
Yes. A blocked filter restricts airflow across the evaporator coil, which reduces cooling capacity and, if it continues, causes the coil to freeze and stop cooling entirely. It is the cheapest and most common cause on this list, and the first thing worth checking.
My AC only struggles on the hottest days. Is that a fault?
Usually not. Systems are sized to a design temperature rather than the record high, so running continuously and drifting slightly above setpoint on an extreme Fresno afternoon is expected behavior. It becomes a fault when the air is not clearly cold at all, when performance has changed from previous years, or when the house keeps warming overnight.
How much does it cost to fix an AC that is not cooling?
In the Fresno area, most repairs fall between roughly $150 and $1,600 depending on the cause. A capacitor is typically $150 to $350, a contactor $150 to $300, a condenser fan motor $400 to $800 and a refrigerant leak repair $400 to $1,600. Compressor failure is the expensive exception at $1,800 to $3,500. See published price ranges.
How quickly can someone come out in Fresno?
Same-day is usually available across Fresno and Clovis, and we are open 24 hours a day, seven days a week. During a peak heat wave the whole valley calls at once, so we give an honest arrival window when you call rather than an optimistic one.
Tried the checks and it is still not cooling?
Real measurements, photos of what we find, and a firm price before anything is touched.
Guidance on this page is general information and not a substitute for a professional diagnosis. Prices shown are typical ranges for the Fresno area and are not quotes. California Heating & AC Repair is operated by Craftline Renovations, Inc. · CSLB License #999179 · Licensed and insured.