Start with the filter
A clogged filter is the number one cause of an AC not blowing cold air. Restricted airflow makes the evaporator coil freeze, and a frozen coil cannot absorb heat. Replace 1-inch filters monthly in summer; 4-inch media filters every 3–6 months.
Check the outdoor unit
Walk outside. Is the fan spinning? Is the coil packed with dust, cottonwood fluff or grass clippings? Arizona dust storms coat condenser coils fast. A gentle rinse with a hose (power off) helps, but a professional coil cleaning restores full capacity.
Low refrigerant means a leak
Air conditioners do not consume refrigerant. If the charge is low, there is a leak — often at a coil, a brazed joint or a Schrader valve. Topping off without repairing the leak is throwing money away. Our AC repair technicians find and fix the leak first.
Failed capacitor
In 115° heat, capacitors fail constantly. Symptoms: outdoor unit hums but the fan does not spin, or the compressor will not start. This is a quick, inexpensive repair that we carry on every truck.
Frozen evaporator coil
Ice on the copper lines or the indoor coil means either airflow is restricted or refrigerant is low. Turn the system off, let it thaw for a few hours, and call for AC not cooling repair.
Thermostat problems
Dead batteries, a tripped condensate float switch or a blown 3-amp fuse in the air handler will make the thermostat go blank or stop calling for cooling. See our thermostat repair page.
Leaky ducts
Attic temperatures in Phoenix hit 140°+. If your ducts leak, you are cooling the attic. Duct sealing can recover 20–30% of lost cooling.
Compressor failure
The worst case. Signs include breaker trips at startup, loud clanking or a compressor that is hot and silent. See AC compressor repair for your options.
When to call
If the filter is clean and the outdoor unit is clear and it still is not cooling, call. Same-day AC repair is available in every Arizona city we serve — find your city on the locations page.
More from the blog
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- Monsoon Season HVAC Tips: Protecting Your AC From Dust Storms and Humidity
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- Commercial HVAC Maintenance in Arizona: Keeping Rooftop Units Alive Through Summer