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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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. ï»¿

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.

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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.

October 28, 2025
As the crisp mornings begin and leaves start to fall in the Statesville area, it’s the perfect time to shift your home-comfort strategy. The transition from summer cooling to fall heating presents unique opportunities (and a few hidden risks) for your HVAC system. At Duncan Heating & Air Conditioning, we want to help you make this seasonal shift smoothly, comfortably and cost-effectively. 1. Take advantage of moderate weather for airflow cleanup One of the best times to act is right now — when you neither need full-on cooling nor full-on heating. That means your system can be inspected, cleaned, and prepared before it’s under heavy load. For example: Remove leaves, pine straw, and other debris from around the outdoor unit so airflow isn’t restricted. Clear return vents, inspect filter access, and check that nothing is obstructed inside your home. This kind of proactive care helps your system run more efficiently and extends its service life. 2. Switch the thermostat but stay ready for temperature swings In fall, you’ll often toggle between the “A/C” and “heat” mode — sometimes in the same day. This means: If you have a heat pump, check that it switches correctly between cooling and heating modes. If you use a furnace, make sure the thermostat is set correctly and the system is ready to kick in when the chill arrives. By doing this early, you avoid that moment when you turn the heat on for the first time and it fails or performs poorly. 3. Replace or upgrade your air filters & check your indoor air quality Summer tends to fill HVAC filters with dust, pollen, and other pollutants. As the weather cools, you may see an increase in indoor allergens (leaves, mold from damp fall air, etc.). So: Change your air filter now — it’s a small cost for big benefits. Consider a higher-quality filter or an indoor air quality check to handle allergens and the transitional season’s humidity changes. Clean filters and good airflow reduce stress on your system and help maintain comfortable air. 4. Inspect your ductwork & vents for leaks and drafts During the summer your HVAC system’s load is high, so it’s easier to ignore inefficiencies. In fall, when you start using heating, weaknesses show up more clearly. What to do: Walk around your home and check for cold spots, drafty rooms, or vents that are blocked. Inspect exposed ductwork (especially in attics, crawlspaces, basements) for visible gaps or disconnected seams. Seal or insulate where needed so when heating starts, you’re not paying to warm up lost air. This improves comfort and lowers monthly energy costs. 5. Consider booking a fall tune-up to get ahead of winter You likely already know about spring checks for your A/C, but fewer homeowners remember a pre-heating season tune-up. Here's why it makes sense: A technician can spot wear from summer, check heating components, test efficiency, and make adjustments before you rely on the system on cold nights. You’ll reduce the chance of emergency breakdowns when temperatures drop and service queues are longer. It’s an investment in peace of mind and better performance for the season ahead. Why now matters Waiting until your first cold morning to act is risky. HVAC issues often start small but become costly fast — especially when demand ramps up. By prepping in this intermediate season, you: Extend equipment life span Avoid higher energy bills Maintain more even comfort levels Minimizing repair interruptions when you least want them Let Duncan Heating & Air Conditioning help If you’re in the Statesville, NC region and want to get ahead of the fall/hunting-season weather shifts, we’re here for you. Whether it’s clearing your outdoor unit, inspecting vents and ductwork, replacing filters, or scheduling your fall tune-up — we’ve got you covered. Contact us today to ensure your home stays comfortable, efficient, and ready for whatever the coming months bring.
September 30, 2025
As we head into fall in North Carolina, the days grow shorter and the nights chillier. It’s the perfect time to start thinking about how your HVAC system can work smarter—not harder—to keep you comfortable without sending your energy bills through the roof. At Duncan Heating & Air Conditioning, we’re always looking for ways to help our customers get more from their systems. Here are practical tips you can use right now to reduce your heating (and cooling) costs this season. 1. Leverage Natural Heat: Use the Sun Strategically Take advantage of sunny days: open curtains or blinds on south- and west-facing windows during daylight hours. This passive solar gain can help warm your home without turning on the heat. Then, as evening arrives, close them to retain the warmth. 2. Adjust Your Thermostat a Few Degrees Every degree matters. Lowering your thermostat by just 1–2 °F during cooler days (or raising it slightly when heating is in use) can yield noticeable energy savings. Use setback settings for when you’re asleep or away from home. A programmable or smart thermostat makes this easy. 3. Seal Drafts & Insulate Strategically Even a well-functioning HVAC system struggles if your home leaks air. Walk around your doors, windows, and baseboards looking for drafts. Use weatherstripping or caulk to seal gaps. Also, check attic and crawlspace insulation—adding a bit more insulation where needed is a relatively low-cost upgrade with long-term payoff. 4. Zone Wisely & Close Rooms You Don’t Use If your home has multiple zones or dampers, reduce conditioning in unused areas. Shut vents in guest rooms, basements, or storage spaces to focus heated air where it matters most. Just be careful not to close too many vents at once (which can affect system pressure). 5. Clean & Schedule Maintenance Now, Before Heating Demand Ramps Up Replace your air filters (if you haven’t recently). Clear debris from around your outdoor unit (if you have a heat pump) so airflow isn’t blocked. Make sure vents, registers, and returns are unobstructed by furniture or rugs. Schedule a professional tune-up: checking electrical, gas connections, combustion (if applicable), duct leaks, and system calibration can reveal small issues before they turn into costly repairs. 6. Use Ceiling Fans & Air Circulation to Your Advantage Many people think ceiling fans only help in summer—but they’re useful in fall too. Switch your fan’s direction to clockwise (low speed) to gently push warm air downward. This helps mix the air and can reduce the need to bump up the thermostat. 7. Monitor HVAC Performance & Watch for Inefficiencies Keep an eye on your energy bills, listen for odd noises, notice uneven heating, or detect higher humidity. If something seems off, call a technician to audit your system. Sometimes a minor adjustment or calibration can restore efficiency. Fall is a transition season—not quite cold, but cooler enough that the habits you set now can make a big difference in comfort and cost. With small changes like smarter thermostat use, sealing drafts, and proactive maintenance, your HVAC system can deliver the comfort you need without wasting energy. If you'd like professional help tuning your system or finding tailored energy-saving upgrades, Duncan Heating & Air Conditioning is here to help. Contact us today to schedule a fall performance check or ask about economical ways to make your heating system more efficient.
August 26, 2025
September may signal the start of fall, but in Statesville and across North Carolina, we all know the summer heat doesn’t just disappear overnight. Many homeowners still find themselves running the air conditioner well into September, which can keep energy bills higher than expected. The good news? A few simple adjustments can help you stay comfortable while keeping costs under control. At Duncan Heating & Air Conditioning, we’ve put together some practical tips to help lower your energy bills as summer lingers on. 1. Adjust Your Thermostat Settings A small change goes a long way. Setting your thermostat just a few degrees higher can make a noticeable difference in your energy use. For example, aiming for 76–78°F when you’re home and 80–82°F when you’re away helps reduce the strain on your system without sacrificing comfort. 2. Use Ceiling Fans to Your Advantage Ceiling fans don’t cool the air, but they circulate it so you feel cooler. This means you can raise your thermostat a degree or two without noticing much difference. Just remember to turn fans off when you leave a room—they only work when you’re there. 3. Keep Up with Filter Changes A dirty air filter makes your HVAC system work harder than it needs to. Replace filters every 30–60 days during heavy use. This not only saves energy but also improves indoor air quality for your family. 4. Seal Air Leaks and Improve Insulation Warm air sneaking in through cracks around windows, doors, or ductwork forces your AC to run longer. A quick weekend project—like adding weatherstripping or sealing duct joints—can make your home more efficient and lower energy bills. 5. Schedule an HVAC Tune-Up Preventative maintenance is one of the smartest ways to save money. A professional tune-up ensures your system is running at peak efficiency, identifies small issues before they become big repairs, and helps extend the life of your unit. 6. Take Advantage of Cooler Nights When evening temperatures drop, consider turning off your AC and opening the windows. Using natural ventilation, even for a few hours, can reduce your cooling costs significantly. Stay Comfortable, Spend Less As summer stretches into September, keeping your energy bills in check doesn’t have to mean giving up comfort. With these small steps—and the help of a trusted HVAC partner—you can stay cool and save money. At Duncan Heating & Air Conditioning, we’re here to help homeowners in Statesville and the surrounding area get the most out of their HVAC systems. Whether you need maintenance, repairs, or advice on improving efficiency, our team is just a phone call away. 👉 Contact us today to schedule your late-summer HVAC service and start saving on energy costs.
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