It’s usually not a good sign when your air conditioner is blowing warm air in your Central Florida home! After all, one of the worst feelings as a homeowner is walking into your home on a hot day to cool off, only to realize that warm air is coming out of your air vents. But what’s causing the warm air to blow, and what can you do about it?
12 Reasons Your AC is Blowing Warm Air
There can be a wide range of reasons why an AC is blowing warm air, from a simple dirty air filter to a unit at the end of its lifespan. Some of these issues you can fix yourself, while others will require the assistance of a professional HVAC service. By understanding the most common culprits for an AC blowing warm air, you can make a confident decision for the comfort of your home.
1. Clogged Air Filters
The air filter is a simple component that protects your indoor air handler. These inexpensive filters keep your evaporator coils and indoor air clean by trapping dust, allergens, and other particles. But, with standard wear and tear, air filters can become saturated over time, restricting airflow and preventing cool air from circulating properly. A clogged filter can also cause your system to overwork, potentially leading to other AC problems.
Solution: Change your air filters every 30 to 90 days. Consider more frequent changes if you have pets, smokers, or allergy sufferers in your home. Upgrading to high-efficiency filters may also help. The frequency and type of filters you should use will depend on several factors in your household, including:
- Square footage of home
- Number of pets
- Number of allergy sufferers
- Number of smokers
- Workload of air conditioner
2. Dirty Evaporator Coils
Dirty evaporator coils are one of the most frequent causes of an AC blowing warm air. The evaporator coils in your indoor air handler absorb and cool the hot air in your home. When these coils become dirty or clogged, they can’t cool the air efficiently, leading to warm air blowing from your vents.
Solution: Professional cleaning for dirty evaporator coils is highly recommended due to the delicate nature of the mechanical and electronic components in modern air handlers. If you have experience with HVAC or similar equipment, you can clean the coils yourself by following these steps:
- Turn the AC system completely off, preferably at the panel and the breaker.
- Locate the coils. They are housed in the air handler near the blower fan. If you have trouble finding them, consult the manual or other resources.
- Fill a spray bottle with a mixture of warm water and regular household cleaning detergent.
- Spray the solution and let it sit for up to 10 minutes.
- Gently wipe away the debris from the coils with a soft cloth.
3. Clogged Condensate Line
A clogged condensate line is another common cause of your AC blowing warm air that comes with a relatively simple and cheap fix. The condensate line carries moisture away from your AC unit during the cooling process. But over time, mold, algae, and other debris can clog this line, obstructing your system’s ability to remove humid air and causing warm air to blow instead. While many systems have an automatic shut-off switch that prevents the unit from running with a clogged condensate line, others will continue running at a diminished capacity.
Solution: Regularly inspect and unclog your AC drain line. Using a wet/dry vacuum or a plumber’s snake can help remove blockages.
For more information, check out our blog:How to Unclog Your AC Drain Line
4. Malfunctioning Compressor
In most systems, the compressor is the big outdoor unit that consists of a fan, coil, refrigerant, and other components. The compressor is vital to your AC system, cycling refrigerant to the indoor handler to cool the air. If the compressor malfunctions, it can’t convert refrigerant from a gas to a liquid, leading to your AC blowing warm air instead.
Solution: A malfunctioning compressor typically requires professional repair or replacement. Regular maintenance can help prevent compressor issues. Call an HVAC technician to inspect and test the compressor to diagnose the cause of the malfunction.
5. Refrigerant Leak
Refrigerant is crucial for cooling air; a leak can significantly reduce your system’s ability to produce cold air. Over time, leaks can develop due to causes including an aging system, physical damage, corrosion, and manufacturer defects. Signs of a leak include frosted evaporator coils and warm air blowing from the vents.
Solution: A refrigerant leak should be addressed by a licensed HVAC technician. They can locate and repair the leak and recharge the system with the correct amount of refrigerant.
6. Duct Leaks
Leaks in your home’s ductwork can allow warm air to mix with the cooled air, leading to warmer air blowing from your vents. This is especially true in older homes that haven’t had the ductwork replaced in a long period. Duct leaks can also reduce your system’s efficiency, increasing energy costs.
Solution: Ductwork issues should always be handled by a professional. Having your ductwork cleaned or serviced every three to five years can prevent many of these problems from occurring and improve efficiency.
7. Obstructed Outdoor AC Unit
Obstructions and blockages are often overlooked causes of an AC blowing warm air. Your outdoor AC unit needs to be free of obstructions to function correctly. Obstructions, including overgrown landscaping, leaves, and other debris can clog the unit, causing it to overheat and blow warm air.
Solution: Regularly clear debris and ensure that there’s at least two feet of clearance around the unit. Trim back any nearby plants or trees to prevent future obstructions.
8. Incorrect Thermostat Settings
Have you checked your thermostat to ensure it is set correctly? It’s possible to accidentally set the thermostat to HEAT. The thermostat’s fan setting can also cause the AC to blow warm air. If the fan is set to ON instead of AUTO, it will continue blowing even when a cooling cycle is not running.
Solution: Double-check your thermostat settings, ensuring it’s set to COOL and the fan is on AUTO. If your thermostat is malfunctioning, consider replacing it. We have often seen that AC issues are as simple as a thermostat user error. Check your thermostat before you give us a call!
Is your thermostat bad? Check out our blog: How to Tell if Your Thermostat is Bad
9. Faulty Capacitors
Faulty capacitors may be a less common cause of an AC blowing warm air, but they can still be at the root of the problem. Capacitors are a key electrical component in an AC system that provides the initial energy needed to start the motor and keep it running. If the capacitors are faulty or weak, your AC may struggle to start or blow warm air.
Solution: Capacitors should be tested and replaced by a professional technician. Regular maintenance can help identify capacitor issues before they lead to system failure.
10. Electrical Issues
Although this problem is caused independently of the HVAC, electrical issues can often result in your AC blowing warm air. To function properly, your AC needs a steady stream of electrical power, which is dependent on a series of electrical connections. Loose or damaged wires, tripped breakers, or blown fuses can interrupt the cooling process, resulting in warm air.
Solution: Check your circuit breaker and fuses to ensure they’re functioning correctly. For more complex electrical issues, contact a licensed HVAC technician or electrician to safely diagnose and repair the problem.
11. Undersized AC Unit
AC systems come in a range of sizes to meet the high variation of square footage in homes, apartments, and condominiums. To save on initial installation costs and ongoing energy costs, it can be tempting to put in a smaller, more inexpensive unit. But if your AC unit is too small for your home, it may struggle to keep up with cooling demands, especially during peak heat. This may cause the system to blow warm air as it becomes overworked.
Solution: Have an HVAC professional evaluate your home’s cooling needs and determine if your current unit is appropriately sized. If necessary, upgrading to a properly sized unit will improve cooling efficiency.
12. End of Unit Lifespan
Even the best air conditioners have a limited lifespan, typically 15 to 20 years. As your unit ages, its efficiency decreases, and it may struggle to maintain cool temperatures, leading to warm air blowing from the vents. Keeping up with routine maintenance — such as replacing air filters and having semi-annual tune-ups — can help your unit last longer and perform better during its lifetime, but only to an extent. If you’re following the recommended maintenance and your unit is still struggling to heat and cool properly, it’s probably time to evaluate replacement options.
Solution: Regular maintenance can extend the life of your unit, but if it’s nearing the end of its lifespan, it may be time to consider replacement options. Consult with an HVAC professional to explore modern, energy-efficient systems that can better meet your cooling needs.
AC Repair in Central Florida With Complete Air Mechanical
There’s no reason to live with your AC blowing warm air! Contact the heating, ventilation, and air conditioning experts at Complete Air Mechanical, located in Longwood, FL, today. We’ll ensure that all AC repairs are made in a cost and time-efficient manner. We’ll also explain AC maintenance strategies to help ensure your system keeps you comfortable for many years to come.
Call us today at (407) 915-0144 or schedule an appointment online.