It is late, the house is getting warmer, and you have a decision to make. Call someone now, or wait until morning?

Nobody wants to pay for an after-hours visit they did not need. Nobody wants to sit on a problem that gets worse overnight. What counts as an AC emergency comes down to three questions, and Houston heat changes the answer to one of them. We have repaired air conditioning in Houston homes since 2003.

Below you will find a clear test, the problems that always warrant a call now, and the ones that can wait. Also what to do while you wait, and the point where a hot house stops being an AC problem and becomes a medical one.

It is an emergency if it threatens safety, health, or your home. Comfort alone does not make the list.

Call right away for any of these:

• Burning, hot plastic, or electrical smells
• Smoke, sparks, or scorch marks on the unit
• A breaker that trips again every time you reset it
• Water actively running into your house
• Total failure in extreme heat with an infant, an older adult, or someone with a health condition inside
• Loud grinding, banging, or screeching from the outdoor unit

These can usually wait for a scheduled visit:

• Warm air while the house is still holding a safe temperature
• One vent weaker than the rest
• A higher electric bill
• A noise your system has always made
• A filter you can change yourself

One more thing decides it. If anyone in the house shows signs of heat illness, that is a call to 911, not to an air conditioning company.

Six problems answer the safety question for you. Any one of them means stop and call.

Burning, hot plastic, or electrical smells. Shut the system off at the breaker, not just the thermostat. That smell usually means a motor, a wire, or a control board is overheating.

Smoke, sparks, or scorch marks. This is a fire risk. Get everyone out and call 911 first if you see flame or smoke.

A breaker that keeps tripping. Your breaker is doing its job. It cuts power because something is drawing too much current. Resetting it over and over removes the protection and leaves the fault in place.

Water running into your house. Your AC pulls moisture out of the air and drains it away. When that drain line clogs, the water goes somewhere else. In Houston homes with attic units, that somewhere is your ceiling.

Total failure in extreme heat with someone vulnerable inside. Infants, adults over 65, anyone with a heart or lung condition, anyone on medication that affects heat tolerance, and pets. A house without cooling in August heats up faster than most people expect.

Grinding, banging, or screeching outside. Those sounds point to a failing fan motor, bearings, or compressor. Shut the system down. Running it while it makes that noise turns a repair into a replacement.

Plenty of AC problems are real problems that can wait until morning. Here is what belongs on a scheduled visit.

Warm air while the house is still comfortable. Something is wrong and it needs attention. But if your indoor temperature is holding steady and everyone is fine, this is a next-day call.

One weak vent. A single room underperforming usually points to a duct issue or a closed damper. The rest of your system is working.

A higher electric bill. This tells you the system is losing efficiency. It is a reason to schedule a tune-up, not a reason to call at midnight.

A noise your system has always made. Familiar sounds are not the concern. New sounds are. If it has hummed that way for three summers, note it and mention it at your next visit.

A dirty filter. This is the one fix worth trying yourself. A clogged filter chokes airflow and causes several problems that look worse than they are.

Mild short cycling in the afternoon. Systems work hardest during the hottest part of a Houston day. Occasional short cycling then is worth reporting, not worth an emergency call.

Waiting until morning is often the right call, and after-hours service is priced differently than a scheduled visit. If you are unsure which bucket you are in, call and describe what is happening. We would rather talk you through it than send a truck you did not need.

Three problems sit between the two lists. Here is how to place them.

Refrigerant leaks. Nobody needs to leave the house. But this is not a wait-a-week problem either. A system running low on refrigerant puts strain on the compressor, and a compressor is the most expensive part of your AC. Refrigerant is handled only by licensed technicians.

Frozen evaporator coils. Ice on the coil means airflow or refrigerant is off. Turn the cooling off and switch the fan to on. That thaws the ice without running the compressor against a blocked coil. Running a frozen system is one of the faster ways to burn out a compressor.

Drain line clogs. The emergency here is water damage, not cooling loss. Water sitting in a pan is different from water reaching your ceiling. In Houston, where so many systems sit in the attic, that difference shows up on your drywall.

Hissing or bubbling sounds. These often point to a refrigerant leak. Worth a same-day call.

There is no single temperature that makes it an emergency. What matters is who is in the house and how they are doing.

Houston makes this harder than most places. Our humidity keeps sweat from evaporating, and evaporation is how your body sheds heat. A house also gains heat through the attic all afternoon and holds it well into the night. Once cooling stops in August, the indoor temperature climbs and stays there.

Some people are at higher risk than others:

• Infants and young children
• Adults over 65
• Anyone with a heart or lung condition
• Anyone taking medication that affects heat tolerance
• Pets

Older adults often do not feel thirsty when they should. That makes checking on them more reliable than waiting for them to say something.

Heat exhaustion shows up as heavy sweating, cold or clammy skin, dizziness, headache, nausea, muscle cramps, weakness, or fainting. Move the person somewhere cooler, loosen clothing, and give small sips of water.

Heat stroke is different, and it is a 911 call. The signs are confusion, slurred speech, fainting, hot skin that may be dry, a fast strong pulse, or someone who has stopped sweating in the heat. Call 911 first. Move them somewhere cooler and use cool cloths while you wait. Do not give a person with these signs anything to drink.

That is the line worth remembering. Feeling awful in the heat is one thing. Not thinking or acting normally is another, and that is when you call 911, not us.

If your house is not holding a safe temperature, go somewhere that is. Houston operates cooling centers during heat events.