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Why Is My Air Conditioner Blowing Hot Air?

As the summer season brings brighter days and warmer temperatures, you are likely running your air conditioner more and more frequently. This additional usage can spell trouble for older units or AC systems that have not received annual maintenance. You likely expect your AC system to keep your home cool and comfortable. But what happens when you find your air conditioner blowing hot air? Let’s take a look at why your AC might be blowing warm air and what you can do about it. 

Misconfigured Thermostat Settings

When you find that your AC is blowing warm air, it can be easy to panic and assume it is an issue with your air conditioner. However, there is a chance that this warm air is the result of your thermostat settings. Two setting configurations can lead to this issue:

  • Warm Temperature Settings: First, double-check to ensure that your thermostat is set to “cooling” instead of “heating.” Especially during colder summer nights, there is a chance that someone in your household made this thermostat switch without turning your AC back on in the morning. 
  • ON Fan Settings: Next, check to see if your thermostat fan is turned to ON or AUTO. HVAC systems have a fan to help distribute your comfortable air. When this fan is set to AUTO, it will only run your fan when your air conditioner is producing cold air. When your thermostat’s fan is set to ON, it will circulate air 24/7.

For example, you might choose the thermostat fan ON setting instead of AUTO if you have an air purifier integrated into your HVAC system. This setting lets your air purifier run when your home is not in a cooling cycle. However, once your home has reached its desired temperature, your fan will begin circulating air without cooling it first—leading to warm airflow.

Before you start seeking out AC service or AC repair, double check your thermostat settings and confirm that your AC is turned on and the fan is set to AUTO. 

Dirty Home Air Filters

Before air can be distributed throughout your home, it must pass through your air filters. Blocked filters create stress for your system, which may lead to warm airflow. When you notice that your AC unit is blowing warmer air, take a moment to check the status of your filters. If you find your air filters dirty, see if replacing them restores your cold airflow. 

Frozen AC Evaporator Coil

A frozen evaporator coil will block your refrigerant heat transfer—leading to warm air distribution. Unfortunately, a variety of HVAC issues can cause your coil to freeze, including: 

  • Dirt, dust, or buildup on the evaporator coil
  • Clogged drain line
  • Refrigerant troubles 
  • Low airflow from clogged air filters
  • Dirty or malfunctioning blower

A frozen evaporator coil will interrupt the flow of your refrigerant, causing your system to blow warm air. If you notice your evaporator coils are frozen or covered in ice, turn off your air conditioning unit. Running your AC with frozen coils will strain your air conditioner and could damage your compressor or blower fan. Next, contact a professional for support. Your coils could easily become further damaged without the right care. 

Low Air Conditioner Refrigerant Levels

Your refrigerant is responsible for transferring the heat out of your circulating air. If the refrigerant is low or leaking from your air conditioning system, there is no way for the AC unit to cool the air it brings into your home.

Low air conditioning refrigerant has two potential culprits:

  • New AC Systems: Experienced AC professionals carefully measure the exact amount of refrigerant needed by your system. However, this measurement process requires a heat load. When you have a new AC system installed during a colder month, the refrigerant measurement may be off. In this case, your air conditioning technician will be able to repair this issue with a simple AC recharge. 
  • Leaking AC Refrigerant: Your refrigerant exists inside a sealed system—meaning that your air conditioner recirculates the same refrigerant for the lifespan of your unit. However, if there is a break or leak somewhere in your air conditioner, it will let your refrigerant escape. A professional can find and address the leak at its source to restore your AC functioning. 

The three most common signs of low refrigerant are ineffective air conditioning (such as blowing warm air), higher energy bills, and shut-down AC functioning.

Local Sacramento AC Repair Services: Give Bonney A Call

Summer is not the time for your AC unit to start blowing hot air. Thankfully the AC repair, maintenance, and replacement professionals at Bonney can help. Most of these air conditioning troubles can be prevented or caught early with Bonney Beyond seasonal AC maintenance. Our technicians drive fully-stocked trucks, helping us complete same-day AC repairs. We also offer coupons, deals, and discounts to make our everyday low prices even more affordable. Get industry-leading air conditioning service in the Sacramento area by partnering with Bonney today!