AC Blowing Warm Air in Florida Heat? Read This First

Vents are open. The blower is going. Air is moving. But it is room temperature, or warmer. Outside it is 90 plus and the house is climbing. This is the call we get most often in Panama City Beach in June and July.

Four causes account for almost every "warm air" call we run. Some you can check before you pick up the phone.

1. Thermostat is set wrong

It happens more than you think. Smart thermostats reset after power outages. Kids change settings. The fan gets stuck on "On" instead of "Auto" so it blows even when the system is not cooling.

Walk over and check:

• Mode is set to Cool, not Heat or Off
• Set point is at least a few degrees below the room temp
• Fan is on Auto, not On
• Batteries are good (if applicable)

If the fan is set to On, the blower runs even when the system is not actively cooling. So you feel air, but it is not cool air. Set it to Auto.

2. Outdoor unit is not running

Your indoor unit can blow air all day. If the outdoor unit (the condenser) is not running, the air will never be cold. The outdoor unit is what removes heat from the refrigerant. No outdoor unit, no cooling.

Walk outside. Listen for the fan. If it is silent, that is your problem.

Check three things:

• The disconnect. Right next to the outdoor unit is a small box with a pull or a switch. Make sure it is in the On position.
• The breaker. Inside your main panel, find the breaker labeled "AC" or "Condenser." If it is tripped, reset it once. If it trips again, stop and call.
• The capacitor. If you hear a hum from the outdoor unit but the fan does not spin, you probably have a bad capacitor. We replace these all summer in Panama City Beach. Cheap part. Quick fix. Call us.

3. Low refrigerant

Refrigerant is the working fluid that absorbs heat from inside your house and dumps it outside. If the level drops, you cannot move heat out. Air still blows, but it is not cold.

Refrigerant does not "get used up." Your AC is a sealed loop. If it is low, you have a leak somewhere. Common spots: the outdoor coil (corrosion from salt air on the coast), the indoor coil, or the line set joints.

Signs of a refrigerant problem:

• Cooling worked fine last summer, weak this summer
• Indoor coil is freezing up (see below)
• Hissing sound near the unit
• Ice on the copper line outside
• System runs constantly and never reaches set temp

This is a tech problem. We will find the leak, repair it if reasonable, and recharge to the manufacturer specification.

4. Frozen indoor coil

Pull the panel off your air handler (or just look at the copper line going into it). If you see ice or really thick condensation on the line, the indoor coil is frozen.

A frozen coil cannot transfer heat. You are essentially blowing air across a block of ice, and ice is bad at picking up heat.

Most common causes:

• Dirty filter restricting airflow
• Blocked vents or returns
• Low refrigerant
• Bad blower motor

What to do: turn the AC off at the thermostat, set the fan to On (Auto means the fan also stops, you want to thaw the coil). Let it run for a few hours. Once thawed, change the filter and try again. If it freezes back up, call us.

We have a full guide on this: Frozen AC coil: what that block of ice actually means.

Why this happens so much in coastal Florida

Three reasons we see warm air calls more here than just about anywhere:

• Salt air corrosion. Outdoor coils on the coast develop pinhole leaks faster. Lower refrigerant follows.
• Heavy run time. AC systems on the Emerald Coast run almost year round. They wear out faster than systems in cooler climates.
• Dirty coils from humidity and pollen. The combination of moisture, salt and pine pollen creates a film on outdoor coils that nothing inland deals with.

The fix is simple. Twice-a-year maintenance with a real coil washing catches almost all of this before it becomes a no-cooling call. Our $292 maintenance plan is the cheapest insurance against these problems.

Frequently asked questions