Emergency AC Repair Guide: What to Do When Your AC Fails

An air conditioner failing in the Rio Grande Valley in July is not a minor inconvenience. Indoor temperatures can reach the nineties within a few hours, and the humidity keeps the house from shedding that heat overnight.

Here is exactly what to do, in order.

Step 1: three checks, two minutes#

Before calling anyone, rule out the free fixes.

Check the thermostat. Confirm it is set to COOL, not OFF or HEAT, and that the target temperature is at least a few degrees below the current room temperature. If it is a battery powered thermostat with a blank screen, replace the batteries.

Check the breakers. Go to your electrical panel. Air conditioners usually have two breakers: one for the outdoor unit, often a double pole 30 to 60 amp, and one for the indoor air handler. A tripped breaker sits between ON and OFF. Push it fully to OFF first, then firmly to ON.

Also check for a separate disconnect switch on the wall near the outdoor unit, and a service switch near the indoor unit that looks like a light switch.

Check the air filter. Pull it and hold it to a light. If you cannot see light through it, replace it. A badly clogged filter can freeze the coil and stop cooling entirely.

Step 2: look and listen outside#

Walk out to the outdoor unit while the system is calling for cooling.

The fan should be spinning and you should hear the compressor running.

• Fan spinning, compressor running, but no cold air indoors: likely a refrigerant, coil, or airflow problem. Call.
• Fan not spinning, unit humming: almost certainly a failed capacitor. Call. Do not open the unit.
• Nothing at all, no sound: electrical. Recheck the breaker and disconnect, then call.
• Ice visible on the copper line: turn cooling off at the thermostat and set the fan to ON so the coil thaws.

Step 3: decide whether this is an emergency#

Not every failure needs a middle of the night call. These do.

Call immediately if:

• You smell burning, hot plastic, or an electrical odor, or see smoke. Switch the system off at the thermostat and at the breaker first.
• A breaker trips again right after you reset it. Leave it off.
• Water is dripping through a ceiling or running down a wall. Shut the system off at the thermostat to stop the source.
• The indoor temperature is above 80 degrees and an infant, an older adult, or someone with a heart or lung condition is in the home.

That last one is a medical threshold, not a comfort one. Heat exposure indoors during a Valley summer is genuinely dangerous for vulnerable people, and it develops faster than most people expect.

It can usually wait until morning if:

• The house is warm but tolerable and nobody in it is vulnerable
• The system is cooling poorly rather than not at all
• You noticed ice and have already switched to fan only

Step 4: what to tell the dispatcher#

The more specific you are, the better the odds the right parts are on the truck.

• What the system is doing and what it is not doing
• Whether the outdoor fan is spinning
• Whether you hear a hum, a click, or nothing
• Whether you see ice, water, or anything burned
• What you have already checked
• Whether anyone in the home is medically vulnerable
• The equipment brand and rough age if you know them

Step 5: keep the house as cool as possible while you wait#

These make a real difference, and every one of them is free.

Close blinds and curtains on the south and west sides. Solar gain through glass is one of the largest heat loads on a Valley home. This is the single most effective thing on this list.

Run ceiling fans, but only in occupied rooms. Fans do not cool a room, they make people feel roughly three to four degrees cooler by moving air across skin. A fan in an empty room does nothing but add heat from the motor.

Keep interior doors open so air can circulate through the house rather than stratifying room by room.

Do not use the oven, stovetop, or dryer. Each of them adds significant heat and, in the case of the dryer and stovetop, moisture.

Run bathroom exhaust fans after showers so moisture leaves the house.

Drink water and stay in the lowest, shadiest part of the house. Heat rises, so a ground floor room on the north side will be the coolest space available.

Check on everyone, particularly older adults, infants, and anyone with a chronic condition. Signs of heat illness include headache, dizziness, nausea, confusion, and stopping sweating. Confusion or hot dry skin means call 911, not an HVAC company.

Consider relocating for a few hours if the house becomes genuinely unsafe. A mall, a library, or a relative's home is a reasonable answer while you wait.

What not to do#

Do not open the outdoor unit. Capacitors store a substantial electrical charge even after power is disconnected, and they can deliver a serious shock. This is the most common way homeowners get hurt trying to help.

Do not add refrigerant. It requires EPA certification, it is not a fix for a leak, and an overcharged system performs worse and can damage the compressor.

Do not keep resetting a breaker that trips repeatedly. It is protecting you from a short or an overloaded motor.

Do not chip ice off a frozen coil. The tubing is thin and easily punctured, which turns a repair into a much bigger repair.

Do not run the system with ice on it. Turn cooling off and the fan to ON.

What the technician should do#

A proper emergency diagnosis is not a guess at a part. It should include:

• Checking airflow and filter condition
• Testing capacitors under load against their rated values
• Inspecting the contactor and checking amp draw against the nameplate
• Measuring refrigerant pressures with superheat and subcooling
• Inspecting the condensate system and float switch
• Explaining the cause, the fix, and the price before starting work

Then, after the repair, verifying that the temperature split across the coil, the pressures, and the amp draw are all where they belong.

Ask what caused the failure, not just what failed. A capacitor that died because the condenser coil is packed with dust will die again.

How to avoid the next one#

Most emergency calls we run trace back to something that was findable months earlier.

• Change filters every 30 to 60 days
• Pour a cup of distilled white vinegar down the condensate drain every two months
• Rinse the condenser coil twice a year, gently, from the inside out, breaker off
• Keep two feet of clearance around the outdoor unit
• Get a cooling tune up in February or March, with capacitors tested under load

That list prevents the majority of the emergency calls that come in during July.

The short version#

Thermostat, breaker, filter. Then look at whether the outdoor fan is spinning. Burning smells, repeated breaker trips, ceiling water, or a hot house with a vulnerable person in it all mean call now. While you wait, close the blinds, run fans where people are, keep doors open, and drink water.