Phoenix Extreme Heat Warning: What Record Heat Means for Your AC

The current Phoenix extreme heat warning is more than another uncomfortable stretch of Arizona weather. Record temperatures are placing enormous pressure on residential air conditioners, increasing electricity demand and exposing AC problems that may have gone unnoticed during milder weather.

The National Weather Service Phoenix office reports that afternoon temperatures across lower-desert communities will remain several degrees above normal. Overnight temperatures in the 80s and lower 90s provide very little relief for homes or air-conditioning systems.

When outdoor temperatures remain extremely high after sunset, an AC system may continue running for hours. Longer operating cycles increase electricity consumption and place additional stress on capacitors, motors, compressors and other important components.

The connection is clear: extreme outdoor temperatures cause AC systems to operate longer, and that increased cooling demand is now contributing to record electricity use across Arizona.

Phoenix Extreme Heat Warning Extended Through August 28, 2026

The National Weather Service extended the Phoenix-area Extreme Heat Warning through Friday, August 28, 2026.

The agency uses its HeatRisk system to explain the potential health effects of forecast temperatures. According to the National Weather Service, “Major” heat presents a risk to most people, while “Extreme” heat creates a risk for everyone without adequate cooling and hydration.

The National Weather Service also explains that an Extreme Heat Warning is issued when forecasters have high confidence—generally 80% or greater—that dangerous heat conditions will occur.

This is important for Arizona homeowners because air conditioning is not simply a comfort feature during an extreme heat warning. It is an essential part of maintaining a safe indoor environment.

Arizona Breaks Its Electricity-Demand Record Twice

The pressure on Arizona air conditioners can be seen in the state’s electricity statistics.

According to Arizona Public Service, APS customers set a new all-time peak electricity-demand record on August 2, 2026.

Customers used 9,164 megawatts of electricity between 6:00 and 7:00 p.m.

That exceeded the previous record of 9,053 megawatts established on July 24, meaning APS customers broke the electricity-demand record twice in less than two weeks.

APS estimates that one megawatt can provide enough electricity for approximately 160 Arizona homes. Based on that estimate, the 9,164-megawatt record represents enough electricity to serve the equivalent of approximately 1.46 million Arizona homes at one time.

Why did the record occur between 6:00 and 7:00 p.m. instead of during the middle of the afternoon?

Even after the sun begins setting, Arizona roofs, walls, windows, pavement and surrounding surfaces continue releasing heat accumulated throughout the day. At the same time, residents return home, lower their thermostats and use appliances.

That combination causes residential electricity demand to remain extremely high during the early evening.

Can Extreme Heat Damage Your AC?

Extreme heat does not automatically damage a healthy, properly maintained air conditioner. However, it forces the system to operate longer and under more demanding conditions.

An air conditioner works by absorbing heat from inside the home and releasing it through the outdoor condenser. When the temperature outside exceeds 110 degrees, releasing that heat becomes more difficult.

Longer operating cycles place additional pressure on:

• AC capacitors
• Compressors
• Condenser fan motors
• Indoor blower motors
• Electrical connections
• Refrigerant lines
• Evaporator and condenser coils
• Air filters
• Ductwork

A healthy system may continue operating normally throughout the heat wave. However, a dirty filter, weak capacitor, failing motor, refrigerant problem or airflow restriction may prevent the system from keeping up.

Extreme heat often exposes an existing weakness rather than creating an entirely new problem.

Homeowners who notice declining AC performance can review Scott’s Phoenix air conditioning and heating services before a minor issue becomes a complete loss of cooling.

Is It Normal for Your AC to Run Constantly During a Phoenix Heat Wave?

Long AC cycles can be normal during a Phoenix extreme heat warning.

Your air conditioner must work against:

• Outdoor temperatures exceeding 110 degrees
• Heat entering through windows and exterior doors
• Heat stored in walls, ceilings and roofing materials
• Hot attic spaces
• Warm or leaking ductwork
• Direct afternoon sunlight
• Heat produced by appliances and electronics

However, there is an important difference between an air conditioner running continuously and an air conditioner running continuously without cooling the house.

If the system is producing cold air and maintaining a reasonably stable indoor temperature, it may simply be responding to extreme outdoor conditions.

If the AC runs continuously while the indoor temperature keeps increasing, something may be wrong.

Scott’s has a complete guide explaining why an AC may be running but not cooling.

Five Warning Signs Your AC Is Struggling

1. The indoor temperature keeps increasing

Your AC may not reach an unusually low thermostat setting during extreme heat. However, it should still produce cold air and help maintain a reasonably stable indoor temperature.

If the temperature inside continues increasing throughout the day or remains high overnight, the system should be evaluated.

2. Warm air is coming from the vents

Warm air may be connected to:

• An incorrect thermostat setting
• A tripped breaker
• A failed capacitor
• Low refrigerant
• A frozen evaporator coil
• A compressor problem
• Another electrical or mechanical issue

Confirm that the thermostat is set to “cool” and below the current indoor temperature. If the vents continue producing warm air, professional diagnosis may be necessary.

3. Airflow has become weak

Weak airflow may be caused by a clogged air filter, frozen evaporator coil, blocked ductwork, closed vents or a blower motor problem.

Restricted airflow also forces the system to operate longer, increasing energy consumption and pressure on the equipment.

4. The system makes unusual noises

Buzzing, grinding, rattling, screeching or repeated clicking should not be ignored.

These sounds may indicate a loose component, electrical issue, failing motor or damaged fan. Turning the system off until it can be inspected may prevent additional damage.

5. Your electricity bill increases unexpectedly

Higher summer electricity bills are normal in Arizona because AC systems operate longer.

However, a sudden increase that cannot be explained by weather, thermostat settings or household activity may indicate that the AC is losing efficiency.

Homeowners concerned about repair expenses can learn what influences the cost of AC repair in Phoenix.

Arizona Heat Statistics Show Why Working AC Matters

The Arizona Department of Health Services states that Arizona is one of the hottest places on Earth from May through September and that heat-related illnesses are common during the summer.

Maricopa County’s current heat-surveillance dashboard is updated weekly during the May-through-October heat season.

As of August 21, 2026, Maricopa County had confirmed 81 heat-related deaths, while more than 500 additional possible heat-related deaths remained under investigation.

The county’s official 2025 Heat-Related Deaths Report provides additional context:

• 37% of heat-related deaths occurred during August.
• A heat-related death occurred every day for 85 consecutive days between June 13 and September 5.
• 357 heat-related deaths occurred during that 85-day period.
• Approximately 60% of heat-related deaths involved people age 50 or older.
• 42% of heat-related deaths occurred during excessive-heat warnings.
• The National Weather Service issued five excessive-heat warnings covering 31 days in 2025.

These government statistics demonstrate why the failure of a home’s air-conditioning system should be taken seriously, especially when children, older adults, pets or people with medical conditions are present.

The National Weather Service advises people to remain in air-conditioned spaces and stay hydrated during extreme heat. People who do not have access to reliable air conditioning can call 211 for information about cooling centers, transportation and other heat-relief services.

Air Conditioning Uses a Significant Share of Household Energy

Cooling a home is one of its largest energy expenses.

The U.S. Department of Energy reports that more than 40% of average household energy use goes toward heating and cooling.

The Department of Energy also reports that modern air conditioners use approximately 50% less energy than systems manufactured in 1990.

However, even an efficient system can consume substantial energy when it operates continuously during a Phoenix extreme heat warning.

System condition, equipment age, thermostat settings, insulation, windows, ductwork and maintenance can all affect how much electricity an AC uses.

What Temperature Should You Set Your Thermostat?

There is no perfect thermostat setting for every Arizona home.

The best setting depends on:

• The age and condition of the AC system
• The home’s insulation
• Window quality and sun exposure
• Air leakage around doors and windows
• Ductwork condition
• The size and layout of the house
• Personal comfort and health needs

Setting the thermostat dramatically lower will not make the house cool faster. It only tells the air conditioner to keep operating until it reaches the selected temperature.

If the home is currently 82 degrees, lowering the thermostat from 78 to 65 will not cause the vents to produce colder air. It will simply cause the system to continue running.

Read Scott’s guide to the ideal house temperature during an Arizona summer for additional information.

How to Reduce Pressure on Your AC During Extreme Heat

Arizona homeowners can take several practical steps during an extreme heat warning.

Replace a dirty air filter

A clogged filter restricts airflow, makes the system work harder and may contribute to a frozen evaporator coil.

Check the filter regularly during periods of heavy AC use.

Keep exterior doors and windows closed

Every open door allows hot outdoor air into the house. Check for visible gaps around doors and windows where cooled air may escape.

Close blinds and curtains

Closing window coverings during the hottest part of the day can reduce the amount of solar heat entering the home.

Keep the outdoor unit clear

Leaves, weeds and loose debris around the outdoor condenser may interfere with airflow.

Keep the area surrounding the unit clear, but do not open the equipment or spray electrical components.

Limit indoor heat production

Ovens, dryers and other heat-producing appliances add heat to the home. When practical, use these appliances during cooler hours.

Use a reasonable thermostat setting

Constantly changing the thermostat or selecting an extremely low temperature does not help the system cool faster.

Choose a comfortable, reasonable setting and monitor whether the system can maintain a stable indoor temperature.

Respond to warning signs early

Weak airflow, unusual noises, warm air and rising indoor temperatures may be early signs of a developing problem.

Addressing the issue early may help prevent a complete AC breakdown during the hottest part of the day.

When Should You Call for AC Repair in Phoenix?

Contact a qualified HVAC professional when your system:

• Blows warm air
• Cannot maintain a safe indoor temperature
• Produces weak airflow
• Freezes or develops visible ice
• Leaks water
• Makes unusual noises
• Produces a burning smell
• Repeatedly trips the circuit breaker
• Turns on and off excessively
• Stops operating completely

Do not repeatedly reset a breaker that continues tripping. A recurring trip may indicate an electrical or mechanical problem that requires diagnosis.

Scott’s AZ Services provides AC repair in Phoenix for air conditioners struggling during extreme Arizona temperatures.

Scott’s also offers local Ahwatukee AC repair and serves Scottsdale, Tempe, Chandler, Gilbert, Mesa and surrounding Valley communities.

The Connection Between the Phoenix Heat Warning and Your AC

The current statistics connect directly to what is happening inside Arizona homes:

1. The Phoenix extreme heat warning indicates a high likelihood of dangerous temperatures.
2. High daytime and overnight temperatures cause homes to retain more heat.
3. Air conditioners must operate longer to remove that heat.
4. Longer AC operation increases electricity use.
5. APS recorded its highest electricity demand in history.
6. Extended operation places more stress on AC components.
7. Extreme heat can expose weak or failing parts.
8. Early diagnosis may help prevent a complete breakdown.

If your AC runs continuously but produces cold air and maintains a stable indoor temperature, it may simply be responding to the heat wave.

If it runs continuously while your home becomes warmer, airflow weakens or the system develops unusual noises, it should be inspected.

Scott’s AZ Services provides professional AC diagnostics, maintenance, repair and replacement throughout the Phoenix area.

View all Scott’s AZ Services service areas or call 602-345-0055 to schedule service.

Frequently Asked Questions About the Phoenix Extreme Heat Warning

How long will the Phoenix extreme heat warning last?

The National Weather Service extended the current Phoenix-area warning through August 28, 2026. Weather alerts can change, so residents should check the official National Weather Service Phoenix forecast for current information.

Can extreme heat damage an air conditioner?

Extreme heat forces an air conditioner to operate longer and under more demanding conditions. This can increase wear and expose weak capacitors, failing motors, airflow restrictions, refrigerant problems and other existing issues.

Is it normal for an AC to run all day during a Phoenix heat wave?

Long operating cycles may be normal when temperatures exceed 110 degrees. However, an AC that runs constantly while producing warm air or allowing the indoor temperature to rise may need professional service.

Why is my AC running but not cooling?

Possible causes include a dirty filter, frozen coil, failing capacitor, refrigerant problem, thermostat issue, restricted airflow or compressor failure. An HVAC technician must inspect the system to identify the actual cause.

Should I lower my thermostat during an extreme heat warning?

Setting the thermostat dramatically lower does not make the system cool faster. Use a reasonable setting and watch whether the AC produces cold air and maintains a stable indoor temperature.

When should I call an AC repair company?

Request service if the system blows warm air, produces weak airflow, develops ice, leaks water, makes unusual noises, repeatedly trips a breaker or cannot maintain a safe temperature.