If your AC quits during a heat wave, check the breaker, thermostat batteries, and air filter first. If it won't restart, prioritize safety - heat can be dangerous fast. Request emergency AC repair; after-hours visits start around $150 to $500+ before repairs, and demand may extend wait times.
Likely causes
| Cause | What's happening |
|---|---|
| Tripped breaker | High demand can trip the outdoor unit's breaker. |
| Failed capacitor | Heat stress is a leading summer cause of no-start. |
| Overheated compressor | May shut down on a safety control. |
| Thermostat failure | Dead batteries or a blank screen can stop cooling. |
- Indoor temps rising fast with kids, seniors, or pets
- Anyone showing signs of heat illness
- No safe cooler location available
If anyone is in danger, or you smell gas, leave the home and call 911 or your utility immediately.
Frequently asked questions
What causes ac stopped working in a heat wave?+
Several issues can produce this symptom, from simple maintenance items to component failure. The likely causes table on this page lists what each cause looks like so you can describe the problem accurately when you request quotes.
Should I call someone right away?+
Call promptly if you see active water, no cooling during Arizona summer heat, burning smells, or repeated breaker trips. Otherwise, gather details and compare two written quotes before approving repairs.
Can PlumbAirAZ diagnose the problem?+
PlumbAirAZ is an Arizona plumbing and HVAC pricing and referral marketplace, not a contractor. We publish local price ranges and route your quote request to independent licensed service providers who contact you directly.
Related pages
Page Summary
- Topic
- AC Stopped Working in a Heat Wave
- Location
- Arizona
- Best for
- Homeowners diagnosing the issue
- Primary action
- Request a professional diagnosis
- Related services
- See related pages
- Last reviewed
- June 2026
Explore more Arizona plumbing and HVAC resources
Compare local price ranges, run a free estimate, and learn how to vet an Arizona contractor before you approve any work.
Cost guides
City pricing
- Water heater replacement cost in Gilbert, AZ
- Water softener installation cost in Gilbert, AZ
- AC repair cost in Scottsdale, AZ
- AC replacement cost in Scottsdale, AZ
- Heat pump repair cost in Scottsdale, AZ
- Emergency plumbing cost in Scottsdale, AZ
- Tankless water heater installation cost in Scottsdale, AZ
- Slab leak detection cost in Scottsdale, AZ
Tools & comparisons
- New AC Unit Cost Calculator
- AC Repair Cost Estimator
- AC Repair vs Replace Calculator
- Water Heater Replacement Cost Estimator
- Emergency Plumber Cost Estimator
- Drain Cleaning Cost Estimator
- Slab Leak Cost Estimator
- Quote Comparison Checklist
- Cheap vs Licensed AC Repair in Arizona
- Cheap vs Licensed Plumber in Arizona
- Emergency vs Scheduled AC Repair
- Emergency vs Scheduled Plumbing Repair
Homeowner guides
- How much does slab leak detection cost?
- How do I compare plumbing quotes?
- How much does AC repair cost in Phoenix?
- Thermostat Has a Blank Screen
- Water Heater Making a Popping Noise
- No Hot Water
- Arizona HVAC Contractor Checklist
- Arizona Plumbing Contractor Checklist
- Find Water Heater Replacement Near You in Arizona
- Find Drain Cleaning Near You in Arizona
- Find Slab Leak Detection Near You in Arizona
Last reviewed: June 2026
PlumbAirAZ.com is a pricing, education, and referral marketplace. We do not perform the work unless expressly stated. Your request may be shared with or sold to independent HVAC, plumbing, or home service providers that may contact you about your project.