Start here

Quick, low-risk steps

  1. Move vulnerable people to a safe cooled location if needed.
  2. Check thermostat settings and an accessible filter.
  3. Record the exact model and any error code.
  4. Do not open electrical panels or handle refrigerant.
  5. Use our tools to organize evidence before calling a pro.

Homeowner paths

Choose the guide that matches the decision

Start with Safety

Phoenix heat can become dangerous quickly. If your air conditioner stops working, the first priority is the safety of people in the home. Extreme heat can cause serious health problems, especially for older adults, young children, and those with medical conditions.

If anyone shows signs of heat illness—such as confusion, dizziness, or nausea—move them to a cool place and seek medical help. Do not wait for the AC to be fixed. Use fans, cool cloths, and hydration while you assess the situation.

  • Know the signs of heat exhaustion and heat stroke.
  • Identify a nearby cooling center or a friend’s house you can go to.
  • Keep a list of emergency contacts handy.
  • Never leave children or pets in a hot home.

Quick Checks You Can Do

Before calling a contractor, there are a few safe checks you can perform. These steps do not require tools or technical knowledge and can help you describe the problem accurately.

Remember, these are only initial observations. They do not replace a professional diagnosis. If you are unsure or uncomfortable, stop and call a licensed Arizona HVAC contractor.

  • Confirm the thermostat is set to 'cool' and the temperature is lower than the room temperature.
  • Check if the circuit breaker for the AC unit has tripped. If it trips again after resetting, do not reset it again—call a pro.
  • Look at the air filter. A clogged filter can reduce airflow and cause problems.
  • Listen for unusual noises or look for ice on the outdoor unit.

When to Call a Professional

Many AC repairs require specialized knowledge, tools, and licensing. In Arizona, working with refrigerant or electrical components typically requires an EPA-certified technician and a licensed contractor.

If your system is blowing warm air, making loud noises, leaking water, or showing error codes, it is time to call a pro. Use our guides to understand what might be happening and what questions to ask.

  • Refrigerant leaks: Only EPA-certified technicians can handle refrigerant.
  • Electrical issues: Risk of shock or fire. Do not open panels.
  • Frozen coils: Often a sign of airflow or refrigerant problems.
  • Water leaks: Can cause structural damage if not addressed.

Tools to Help You Decide

We offer simple, private tools to help you gather information before you call a contractor. These tools do not diagnose your system, but they help you organize what you see and hear.

Use the No-Cooling Checker to answer a few questions about your system’s behavior. The AC Run Cost Estimator helps you understand potential energy costs. Both are free and require no personal information.

  • No-Cooling Checker: Step-by-step questions to narrow down symptoms.
  • AC Run Cost Estimator: See how settings and usage affect your bill.
  • All tools are private—no data is stored or shared.
  • Results are informational only and not a substitute for professional advice.

Take this with you

Evidence and scope checklist

  • Is anyone in immediate danger from heat? If yes, call 911.
  • Have you checked the thermostat and circuit breaker?
  • Is the air filter clean?
  • Do you see ice, water, or hear loud noises?
  • Have you recorded the model number and any error code?
  • Are you prepared to ask about diagnostic charges, permits, and warranties?
Open the interactive private worksheet →

Common questions

What homeowners ask next

Can I fix my AC myself in Phoenix?

You can perform basic checks like thermostat settings and filter changes. However, any work involving refrigerant, electrical components, or sealed systems should be done by a licensed Arizona HVAC contractor with EPA certification.

How quickly should I act if my AC stops cooling?

In Phoenix heat, act immediately to protect vulnerable people. Move to a cooled space if needed. Then, safely check simple things before calling a professional. Do not delay if temperatures are extreme.

What should I ask an AC repair company before hiring?

Ask about their Arizona license, EPA certification, diagnostic fees, whether they pull permits if required, and what warranties they offer on parts and labor. Get a written estimate before work begins.

Evidence

Sources used for this guide

Research checked July 31, 2026

Optional next step

Need an on-site professional?

Use the guide and worksheet first so you can describe the situation and compare the full scope. A referral is optional; you can also contact a licensed local provider directly.

Referral matching is not enabled yet.

We have not enabled a provider route for this site. Use the checklist to contact and verify local providers yourself; urgent hazards should go to the appropriate emergency or public service.