There’s nothing worse than expecting a blast of cool air from your AC on a sweltering, hot summer day and getting a warm breeze instead. Your air conditioner spewing warm air is a sign that something is wrong. The good news is that many of these problems can be easily detected and diagnosed. Figuring out the cause of the warm air from the AC unit can help you determine whether you can fix the issue on your own or need to bring in a professional.
At 3 Mountains Home Services in Milwaukie, OR, we pride ourselves on helping our customers with home appliances, including AC units. Read on to learn more about the top eight things to check when your AC starts blowing warm air so you can troubleshoot quickly and stay relaxed and comfortable all summer.
1. Check Thermostat Settings
If your AC is blowing warm air, the thermostat should be one of the first things you check. Start by confirming it’s set to COOL mode, not HEAT or FAN, as it’s easy for settings to get changed—especially in a busy household. Next, make sure the temperature is set lower than the current room temperature. For example, if your thermostat is set to 70°F but the room is 72°F, the AC won’t activate. Don’t forget to check the thermostat’s batteries; weak or dying batteries can cause just as many issues as dead ones. Lastly, if you’re using a smart thermostat, review its schedule and ensure it’s properly connected to your Wi-Fi network. These quick checks can often resolve the issue without further troubleshooting.
2. Inspect Air Filter for Clogs and Blockages
A dirty or clogged air filter is a common reason your AC might blow warm air instead of keeping things cool. The air filter’s job is to capture dust, debris, and other airborne particles. However, when it becomes dirty, it can no longer do its job effectively. Over time, debris can accumulate and block airflow, forcing your AC to work harder than it should. This added strain can cause the system to overheat, shut down, or start blowing hot air.
The solution? Simply clean or replace the filter. Most air filters should be replaced every one to three months, depending on usage and manufacturer guidelines. Keeping your air filter clean not only improves your AC’s efficiency but also enhances indoor air quality, ensuring a cooler and healthier home environment.
3. Examine the Condenser Coils
Condenser coils play a crucial role in your AC system by releasing the heat absorbed from your home into the outside air. However, when these coils become dirty, they can’t effectively release heat, causing your AC to blow warm air instead of cooling your space.
To inspect the condenser coils, start by turning off the power to your AC system. Next, remove the protective grilles and panels to access the coils. Look for any dirt, debris, or blockages, such as leaves or grass clippings. If the coils are dirty, you can clean them using a coil cleaner and a soft brush. Be sure to handle the delicate fins carefully to avoid damage.
While this is a task you can attempt yourself, we strongly recommend hiring a professional for thorough and safe cleaning!
4. Assess the Refrigerant Levels
Refrigerant is the lifeblood of your air conditioning system, responsible for absorbing and releasing heat to keep your home cool. If your AC is blowing warm air, low refrigerant levels may be to blame. Unlike fuel, refrigerant doesn’t get “used up,” so a low level typically indicates a leak in the system.
Handling refrigerant is not a DIY task—it requires specialized tools and expertise. If you suspect a refrigerant issue, contact a qualified HVAC professional. They can safely recharge your system, locate and repair leaks, and properly balance the refrigerant levels. Attempting to fix refrigerant problems on your own can be dangerous and may cause further damage. Trusting a professional guarantees safety and restores your AC’s cooling performance and efficiency.
To prevent refrigerant issues, schedule regular maintenance inspections with an HVAC expert. Proactive care can help identify and address potential problems before they disrupt your comfort.
5. Reset Tripped Breakers
If your air conditioner is blowing warm air, a tripped circuit breaker could be the culprit. Circuit breakers can trip due to system failures, power surges, or electrical overloads. To check, locate your home’s electrical panel and see if any breakers are in the “off” position. If you find one, reset it by first switching it fully off and then back on. However, if the breaker trips again immediately, this indicates a more serious issue that needs attention from a qualified technician. While resetting a tripped breaker can quickly restore your AC’s cooling function, frequent trips signal a deeper problem that requires professional inspection.
6. Review Ductwork
If your air conditioner is blowing warm air, leaky ductwork could be the culprit, causing a significant drop in efficiency. Inspect your ducts carefully for cracks, holes, or loose connections—joints and connectors are often problem areas. Seal any leaks using aluminum foil tape or mastic sealant to improve airflow and ensure cool air reaches its intended spaces. For larger leaks or hard-to-reach areas, consider hiring a professional to inspect and repair your duct system. Properly sealed ducts not only keep your home cooler and more comfortable but also boost energy efficiency and enhance your air conditioner’s performance.
7. Check Evaporator Coils
Frost or ice buildup on your evaporator coils can reduce their ability to absorb heat, impacting your home’s cooling efficiency. If you notice frost or ice on the coils, it could indicate issues like low refrigerant levels or restricted airflow. Before inspecting further, turn off the air conditioner and allow the coils to fully thaw. To prevent frost buildup and ensure your air conditioning system runs smoothly, make it a habit to clean and maintain your evaporator coils regularly.
8. Test Blower Motor
A blower motor is essential for distributing cooled air evenly throughout your home. When your air conditioner is running, pay attention to any unusual noises or vibrations, as these could signal an issue. Also, check for consistent and strong airflow from your vents. Weak or insufficient airflow might indicate a malfunctioning blower motor, which can lead to problems with heating as well. To maintain proper air circulation and maximize cooling efficiency, have a qualified HVAC specialist inspect and repair the blower motor at the first sign of trouble.
Contact Us Today
Inspecting these eight key areas will help you identify and fix the problem with your AC blowing warm air. Whether it’s a simple fix like changing the air filter or a more complex task such as checking and refilling refrigerant levels, it’s important to take the time to figure out the issue. Regular maintenance will help you keep your AC running efficiently and prolong its life span. If you’ve gone through these checks and your AC still isn’t performing as it should, it’s time to call a professional. Contact us today for help with your AC unit. We also provide plumbing, drain and sewer, electrical, and heating and cooling services for homeowners.
