An AC failure rises to the level of an emergency when indoor temperatures become dangerous rather than merely uncomfortable — typically when a home cannot be kept below 85 to 90 degrees during a heat wave, or when vulnerable people live in the home. AC emergencies are not simply inconvenient; extreme indoor heat is a documented health threat. Knowing what to do in the first hour can protect your household while you arrange professional help.

What to Do Right Now

First, check the basics before calling anyone: confirm the thermostat is set to COOL and is powered; reset any tripped breaker at the electrical panel (do this only once — if it trips again immediately, stop); and make sure the outdoor condenser unit is running. If the system starts after a breaker reset and produces cold air, monitor it closely. If it stays off or blows warm air, call a licensed 24-hour HVAC technician immediately. While you wait, close all blinds and curtains to block direct sunlight, which can raise indoor temperature by 10 to 20 degrees. Move vulnerable family members to the lowest, coolest floor of the home — heat rises. Use battery or plug-in fans to create airflow, run cold water over wrists, and stay hydrated. If indoor temperature exceeds 90 degrees and you cannot reach a technician quickly, go to a library, shopping mall, or designated public cooling center.

When It Is a Health Risk

Heat-related illness becomes a serious risk when indoor temperatures exceed 90 degrees, particularly for adults over 65, infants and young children, people with heart disease, respiratory conditions, diabetes, or kidney disease, and anyone taking medications that impair the body's cooling response. The CDC and EPA identify extreme heat as the leading weather-related cause of death in the United States. These groups should not remain in an unairconditioned home during a heat wave. If anyone in the home shows signs of heat exhaustion — heavy sweating, weakness, cold or clammy skin, fast or weak pulse, nausea — move them somewhere cool and call 911 if symptoms do not improve. Heat stroke — hot and dry skin, rapid strong pulse, confusion — is a 911 emergency. Do not wait on a technician if someone is showing serious heat illness symptoms; call 911 first.

Getting 24/7 Help

Licensed HVAC companies that offer 24-hour emergency service can often dispatch a technician within one to four hours during normal demand periods, though response times may extend during extreme heat events when many systems fail simultaneously. When you call, describe the exact symptom — what the system does when you try to start it, whether the outdoor unit is running, and how long the problem has been occurring. This helps the technician arrive with the most likely parts. A licensed and insured technician will diagnose the system, explain the cause, and provide a written estimate before any repair work begins. Emergency service calls typically carry a higher diagnostic fee than standard appointments — confirm the rate when you call so there are no surprises. Do not allow anyone to work on the system without providing a written estimate first.