On a hot summer day, the last thing you want to feel stepping inside your home is a wall of warm air from your air conditioner's vents. But this can happen more often than you think, and there are several reasons why your home AC blows warm air. Let us explore some of the most frequent causes and what you can do about them.
Incorrect Thermostat Settings
One reason your AC blows warm air is incorrect thermostat settings. Make sure you set it to "cool" and not "heat" or "fan." It sounds simple, but this oversight is quite common.
Also, ensure the temperature is set lower than the current room temperature. If your thermostat is battery-operated, try replacing the batteries to rule out any power issues.
Clogged Air Filter
A clogged air filter is another common culprit for an AC blowing warm air. When was the last time you changed your air filter?.
If it's been over three months, it's time for a replacement. A clogged air filter restricts proper airflow, causing your AC unit to work harder with less efficiently.
Poorly Calibrated Thermostat
Sometimes, the warm air issue happens because of the thermostat's calibration. If your thermostat isn't reading the room temperature accurately, it won't signal your AC to cool properly. An HVAC technician can help you recalibrate your thermostat to keep this from happening again.
Low Refrigerant Levels or Leaks
Low refrigerant levels will cause your AC to blow warm air. Your cooling system uses refrigerant to absorb heat from your home's air.
If there's a leak or your system is low on refrigerant, it won't cool effectively. Signs of a refrigerant issue include ice buildup on the evaporator coils or a hissing sound coming from your AC unit.
Unfortunately, this is not a DIY fix. Refrigerant handling requires specialized equipment and expertise. Always call a professional if you suspect a refrigerant problem.
Frozen Evaporator Coils Preventing Proper Cooling
If your evaporator coils are frozen, your AC won't cool properly. Restricted airflow or low refrigerant levels often cause frozen coils. If you notice ice on an indoor unit, turn off your AC and defrost the evaporator coils. Once it's thawed, try running it again. However, if the problem persists, call a professional, as this could indicate a more serious issue.
Tripped Circuit Breakers Cutting Power to the Outdoor Unit
Your AC system has two main components—an indoor air handler and an outdoor compressor. If the outdoor unit trips a circuit breaker, your indoor unit will continue to run, but it will only blow warm air.
Check your electrical panel to reset any tripped breakers and blown fuses. If a breaker trips again, don't reset it. Instead, call an electrician. It could be an indication of an electrical problem that requires professional attention.
When To Call a Professional
While you can resolve some AC issues with simple DIY solutions, other problems require certified HVAC technicians. You should contact an HVAC professional if:
- You've checked the thermostat and changed the air filter, but the problem persists
- Do you suspect a refrigerant leak
- Your AC is making unusual noises
- The problem is recurring
- Are you noticing any electrical issues
Regular maintenance, including professional cleaning of your AC unit, is key to preventing many of these issues. By scheduling annual check-ups with a qualified HVAC technician, you can take proactive steps to keep your unit running efficiently and avoid unexpected breakdowns.
Remember, your home’s AC is a complex system, and safety is a top priority. When in doubt, contact Clements Plumbing Heating and Air for all your HVAC repairs in Lamar, MO, at 417-682-3797. They have the tools, knowledge, and experience to ensure your AC is operating safely and effectively, providing you with peace of mind.
