At Duncan Heating & Air Conditioning, we know how frustrating it is when your AC system starts blowing warm air—especially during the peak of a North Carolina summer. If you’ve cranked down the thermostat and your home still feels more like a sauna than a sanctuary, there could be several reasons behind the problem. Here’s a look at some of the most common issues that could be causing your air conditioner to blow warm air, and what you can do about it. 1. Thermostat Issues Let’s start with the basics. Sometimes the issue is as simple as an incorrect thermostat setting. Double-check the mode. Make sure your thermostat is set to “cool” and not “heat” or “fan.” Check the set temperature. Someone in the house may have bumped it up higher than you realized. Dead batteries or faulty sensors in your thermostat can also cause communication issues with your AC unit. If everything looks correct but the problem persists, it may be time for a professional inspection. 2. Dirty or Clogged Air Filter A clogged air filter restricts airflow and can cause your system to overheat and blow warm air. Check your filter monthly and replace it at least every 1–3 months during the cooling season. Dirty filters can lead to poor airflow, frozen evaporator coils, and reduced efficiency overall. This is one of the easiest (and most affordable) problems to prevent. 3. Low Refrigerant Levels Refrigerant is the substance your AC system uses to absorb heat from inside your home. If the system is low on refrigerant (usually due to a leak), it won’t be able to cool effectively. Warning signs include: warm air, ice on the refrigerant lines, and hissing or bubbling noises. Solution: A licensed technician from Duncan Heating & Air Conditioning can locate and repair the leak, then recharge the refrigerant to proper levels. Refrigerant issues are not DIY-friendly, so give us a call if you suspect this is the problem. 4. Dirty Outdoor Unit (Condenser) Your AC’s outdoor unit releases the heat removed from inside your home. If it’s dirty or blocked, the system can’t release heat efficiently, and warm air may circulate back inside. Keep the area around your unit clear of leaves, grass clippings, and debris. If the coils are dirty, a professional cleaning may be needed. Regular maintenance helps keep this part of your system working properly. 5. Electrical Problems or Blown Fuses Electrical issues like a tripped circuit breaker or a blown fuse can shut down key components of your AC system, including the compressor. If the fan is running but the air isn’t cold , your outside unit might not be powered on. Don’t repeatedly reset breakers—call a pro to check things out safely. 6. Frozen Evaporator Coils When airflow is restricted—often due to a dirty filter or blocked vents—the evaporator coils can freeze over. Once that happens, your AC can’t properly cool the air. You may notice ice buildup on the coils or refrigerant lines . Turn the system off and allow it to thaw before restarting, then call a technician to prevent it from happening again. Need Help Fast? Call Duncan Heating & Air Conditioning If your AC is blowing warm air, it’s best to act quickly—what starts as a small issue can turn into a major repair. At Duncan Heating & Air Conditioning, we proudly serve Statesville, NC and surrounding communities with prompt, honest, and affordable HVAC service. Whether you need a quick repair, a full system tune-up, or a second opinion, we’re here to keep your home cool and comfortable all summer long. 📞 Call us today at 704-872-2431 🌐 Or schedule service online today!

When the summer heat hits Statesville, NC, staying cool and comfortable becomes a top priority for homeowners. At Duncan Heating & Air Conditioning, we’re committed to helping you beat the heat with reliable, energy-efficient HVAC solutions tailored to your home’s specific needs. Customized Cooling Solutions for Every Home No two homes are the same—and neither are their cooling needs. That’s why we take a personalized approach to air conditioning service. Whether you need a brand-new system installation, an upgrade to a more energy-efficient unit, or fine-tuning on your existing AC, our experienced technicians make sure your system is set up to keep your entire home cool, even on the hottest Iredell County afternoons. Fast, Reliable AC Repairs When your air conditioner suddenly stops working, you don’t have time to wait around. Our local team is known for prompt, professional AC repair services. We diagnose issues quickly and get your system back up and running, so you’re not left sweating through the summer. We stock a wide range of parts and tools to handle most repairs on the spot. Preventative Maintenance That Pays Off Preventative maintenance is one of the best ways to extend the life of your AC system and avoid expensive breakdowns. Our seasonal tune-ups include thorough inspections, cleaning, and performance checks. This helps your system run more efficiently and keeps your energy bills in check—all while improving indoor air quality and comfort. Energy Efficiency Matters We understand the importance of keeping your home comfortable and cost-effective. That’s why we offer energy-efficient HVAC options, including programmable thermostats and high-SEER-rated air conditioners. These upgrades can significantly reduce your cooling costs and carbon footprint while maintaining optimal indoor comfort. Local Service You Can Count On As a trusted HVAC contractor based right here in Statesville, Duncan Heating & Air Conditioning is proud to serve our neighbors with honest, reliable service. We’re committed to your comfort—and to building long-term relationships with homeowners across our community. Stay Cool with Duncan Heating & Air Conditioning Don’t let summer heat sneak up on you. Whether you’re preparing for the season with a tune-up or facing an unexpected AC issue, Duncan Heating & Air Conditioning is here to help.  📞 Call us today at 704-872-2431 or schedule service online to keep your home cool and comfortable all summer long.