Your Comfort Is Our

#1 Priority.

Since 1931 Duncan Heating & Air Conditioning has been delivering quality AC & Heating services in Statesville, NC and surrounding areas. Let's get you comfortable today with 24/7 HVAC Service & Replacement.

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Refer A Friend & Get Rewarded

At Duncan Heating & Air Conditioning Inc. our customers are our business. We want to give back more than just outstanding comfort to our growing and loyal customers. That is why we are offering any new referral $250 off their install and you can earn a $100 gift card for providing that referral.

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Your all in one HVAC Contractor.

At Duncan Heating & Air Conditioning Inc., we firmly believe that no job, regardless of its scale, is beyond our capability or unworthy of our attention. With our unwavering commitment to excellence, we have established ourselves as a trusted name in the heating and air conditioning industry. Whether it's a large-scale commercial project or a minor residential repair, our team of highly skilled professionals is equipped with the knowledge and expertise to handle any task that comes our way. 

Proudly serving the Statesville, NC and Mooresville, NC areas. Click the button below to discover more about our HVAC services.

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Quality installs that reduce your energy bill and increase your comfort.

Service

No job is too small for our team. We can handle any HVAC related job you have.

Maintenance

Let us maintain your HVAC system and protect your investment.

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Commercial

Commercial HVAC experts that get the job done right.

Super service delivered to our customers

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Our Popular Summer HVAC services

Here are some of our popular Summer services. Learn more below.

Stay Cool & Save Money This Summer!

Spring is the perfect time to schedule an AC tune-up before the summer heat kicks in. Regular maintenance ensures your system runs efficiently, preventing breakdowns when you need cooling the most. A professional tune-up includes cleaning condenser coils, checking refrigerant levels, replacing filters, lubricating moving parts, and testing your thermostat. These small adjustments can significantly improve your system’s performance, extend its lifespan, and lower energy bills.

Fight Spring Allergies with Better Indoor Air Quality

As allergy season arrives, improving your indoor air quality is essential for a healthier home. HVAC upgrades like air purifiers, UV light systems, and high-efficiency air filters can help remove airborne allergens, bacteria, and viruses. Spring is also a great time to check humidity levels—adding a dehumidifier can prevent mold growth and keep your home feeling fresh. Simple steps like replacing air filters regularly can also make a big difference in breathing cleaner air.


Interested in how Duncan can help you fight allergy season? Call us today!

Is Your AC Ready for Summer? Check Your Refrigerant Levels Now!

Low refrigerant levels can cause your AC to struggle, leading to inefficient cooling and higher energy bills. A professional technician can check your system’s refrigerant levels, inspect for leaks, and recharge it if needed. Addressing these issues in the spring ensures your AC is ready to handle the heat without overworking itself, helping you stay comfortable all summer long.

Upgrade Your Comfort with a Smart Thermostat

Upgrading your thermostat in the spring can make a big difference in comfort and energy savings. A smart thermostat learns your schedule, automatically adjusting temperatures for efficiency while keeping your home comfortable. Even a simple recalibration of your existing thermostat ensures accurate temperature readings and prevents unnecessary energy use. With remote control options, you can adjust settings from anywhere, helping you stay cool without high utility bills.

A Higher Standard of Comfort.

Energy efficient equipment at an affordable price. Click below to learn more about our products and how they can improve your comfort.

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Leave Your HVAC Needs To The Pros At Duncan

Trust us to be your all in one HVAC contractor. We are eager to earn your business and improve your comfort.

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Common HVAC Questions

Here are some of the most frequently asked heating and air conditioning questions we receive from our customers. Click below to learn the answers to some of our most FAQs here at Duncan Heating & Air Conditioning:

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  • How often should I service my HVAC system?

    To keep your HVAC system running in tip-top shape, we recommend a maintenance appointment twice a year (once for heat, once for air conditioning). This way, an Oliver technician can check your filters, coils, wiring, housing, motor, and more to make sure you’re getting the most out of your system.

  • How do I know if I need a new HVAC system?

    If your HVAC system requires constant repairs, is 15 years or older, or can’t heat or cool your home properly, we recommend you replace it. When an HVAC system ages, it doesn’t operate as efficiently and could actually end up costing you more money than it should.

  • When should I replace air filters?

    The air filters are one of the most important components of an HVAC. They catch all the airborne particles that you don’t want floating around your home and in your lungs. Once they become full or clogged, your indoor air quality becomes compromised and the lack of airflow can lead to system breakdowns. It is best to replace your air filters about every three months and more often if you live with a smoker or someone with allergies or asthma.

  • What size HVAC unit is right for my home?

    HVACs are not one-size-fits-all. If your unit is too big for the home, it will pump out more air than needed, causing higher bills and an increase in condensation which can lead to mold and algae growth. If the unit is too small, it will become overworked and your home will see uneven temperatures. Your HVAC professionals will help you determine the correct size unit for your home as you begin the process of a new installation.

  • What is a heat pump?

    A heat pump is a part of the heating and cooling system which is installed outdoors and pulls in air to heat or cool your home. They are more eco-friendly than a furnace as they do not burn fossil fuels, require minimal maintenance, are long lasting, and can both heat and cool your home.

  • Why are maintenance appointments important?

    We wouldn’t say maintenance appointments are important. We’d say they are ESSENTIAL! By scheduling these visits from your technician, you’re setting your HVAC up for a successful season of heating or cooling. The technician will clean your unit and replace your air filter, improving your indoor air quality. They will also be able to spot the warning signs of a potential future breakdown and solve them before they cost you down the road.

  • What is HVAC?

    HVAC, which stands for Heating, Ventilation, and Air Conditioning, is an all-encompassing term when it comes to talking about your heating and cooling system in its entirety. While the world of HVAC might seem complicated, it doesn’t have to be confusing for homeowners. Give the Duncan Heating & Air Conditioning team a call for any HVAC service needs you may have!


  • What is the purpose of an HVAC system?

    An HVAC system serves various purposes in your home including maintaining a comfortable indoor environment, preventing moisture and mold growth, eliminating allergens and pollutants, providing fresh air ventilation, and more! 

Two Locations. One Great Company.

With two office locations in Statesville, NC and Mooresville, NC our goal is to ensure that we have Iredell County and surrounding areas covered FAST when it comes to your HVAC service. Having two locations allows us to get to your home or office faster with local technicians in place at both our Statesville, NC headquarters and our new Mooresville, NC office. Call today for any heating and air conditioning service you may need, we will get there FAST!

Statesville, NC

Statesville, NC

Mooresville, NC

Mooresville, NC

Our Blog

Learn more about our tips and services with the Duncan Heating & Air Conditioning blog.

June 24, 2025
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!
May 30, 2025
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.
April 29, 2025
As spring settles in and temperatures start to rise, it’s the perfect time to make sure your air conditioner is ready for the warmer months ahead. But what happens when your AC isn’t performing the way it should? Deciding whether to repair or replace your air conditioner can be a tough call, and at Duncan Heating & Air Conditioning, we’re here to help homeowners in Statesville, NC make the best decision for their comfort and budget. Signs Your Air Conditioner Might Need a Repair Not every issue means you need a brand-new system. In many cases, a simple repair can restore your AC’s performance and extend its lifespan. Here are a few signs that a repair might be the best option: Inconsistent Cooling: If some rooms feel warmer than others, your system may need a tune-up or ductwork inspection. Strange Noises: Grinding, rattling, or buzzing sounds often point to loose components or worn-out parts that can usually be repaired. Higher Energy Bills: A sudden spike in your utility bills could indicate a problem with efficiency that may be resolved with maintenance or minor repairs. Frequent Cycling: If your system turns on and off frequently, it could be due to a faulty thermostat or clogged filter, both of which are typically easy fixes. Regular maintenance can address many of these issues early, saving you from more costly repairs down the line. When It’s Time to Consider Replacing Your Air Conditioner While repairs are often the first choice, there comes a time when replacing your air conditioner makes more financial sense. Consider a replacement if you’re experiencing any of the following: Age of the System: Most air conditioners have a lifespan of 10–15 years. If your system is nearing or past this range, replacement might be more cost-effective than ongoing repairs. Frequent Repairs: Are you calling for repairs more than once a season? The costs can add up quickly, making a new system a smarter investment. Major Component Failures: Issues like a failed compressor or refrigerant leaks can be expensive to fix and may indicate your system is on its last leg. Decreased Energy Efficiency: Older systems tend to lose efficiency over time, leading to higher energy bills. Upgrading to a modern, energy-efficient unit can save you money in the long run. Comfort Issues: If your home never seems to reach the desired temperature or humidity levels, even after repairs, it could be time for an upgrade. Newer air conditioning systems are designed with advanced technology to improve comfort, reduce energy costs, and provide more reliable cooling for years to come. The Benefits of Professional Guidance Deciding between repairing and replacing your air conditioner can feel overwhelming, but you don’t have to make that decision alone. At Duncan Heating & Air Conditioning, our experienced technicians will thoroughly evaluate your system, discuss your options, and help you choose the best solution for your home and budget. We proudly serve homeowners in Statesville, NC with honest recommendations, transparent pricing, and top-quality service to keep you comfortable throughout the spring and beyond. Schedule Your Spring AC Inspection Today! Don’t wait until the summer heat hits—contact Duncan Heating & Air Conditioning today to schedule your spring AC inspection. Whether you need a quick repair or are ready to explore replacement options, we’re here to ensure your home stays cool and comfortable all season long. Stay cool this spring with Duncan Heating & Air Conditioning—your trusted HVAC experts in Statesville, NC! Check out our air conditioning service page to learn more about how we can keep your Statesville, NC home comfortable all summer long.
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