The Most Common AC Problems & How to Avoid Costly Repairs

Keep Your AC Running Smoothly All Year Long

Nothing is worse than your air conditioner breaking down on a scorching hot day. Whether you're dealing with weak airflow, strange noises, or a system that won’t turn on, HVAC repair can be costly if problems aren’t caught early. Knowing the most common AC issues and how to prevent them can save you money and keep your home comfortable.


The Most Common AC Problems & How to Fix Them


1. Weak Airflow

  • Clogged air filters or blocked vents can reduce airflow.
  • Fix: Replace air filters regularly and ensure vents are clear of obstructions.


2. AC Blowing Warm Air

  • Low refrigerant levels or thermostat issues could be to blame.
  • Fix: Check the thermostat settings and schedule an HVAC repair if refrigerant needs recharging.


3. Strange Noises

  • Banging, squealing, or buzzing sounds often indicate loose or worn-out parts.
  • Fix: Turn off your AC and call for HVAC maintenance before damage worsens.


4. High Energy Bills

  • An inefficient AC unit may be working harder than necessary.
  • Fix: Regular HVAC maintenance and installing a smart thermostat can improve efficiency.


5. Frequent Cycling

  • If your AC turns on and off too often, it may have a dirty air filter or an oversized unit.
  • Fix: Clean or replace filters and have a professional assess your system’s size.


6. Water Leaks

  • Clogged condensate drains or frozen evaporator coils can cause water to pool around your unit.
  • Fix: Clear drain lines and schedule HVAC maintenance to prevent future leaks.


7. AC Won’t Turn On

  • Electrical issues, thermostat malfunctions, or a tripped circuit breaker might be the problem.
  • Fix: Reset the breaker and check the thermostat before calling a technician.


How to Avoid Costly AC Repairs


Schedule Regular HVAC Maintenance – Professional tune-ups help prevent major issues. 

Replace Air Filters – Changing filters every 1-3 months keeps airflow strong.

Monitor Your Energy Bills – Spikes in costs may indicate an issue.

Check for Leaks or Strange Noises – Addressing small problems early prevents expensive repairs.

Upgrade to an Energy-Efficient System – Newer HVAC installations can lower costs and improve comfort.


Call ARCO Heating & Cooling for AC Repair & Maintenance

Don’t let small AC issues turn into expensive repairs.

For expert HVAC installation, HVAC repair, or HVAC maintenance in St. Charles, MO.

Call ARCO Heating & Cooling today at (636) 389-6471

A man in a blue shirt is working on a heating system.
By ARCO HEATING AND COOLING September 5, 2025
Stay Warm and Save Big with Modern Heating Solutions from ARCO Heating & Cooling As colder temperatures approach, it’s the perfect time to evaluate your home’s heating system. If your current setup is outdated, inefficient, or struggling to keep up, upgrading to a modern, energy-efficient system can make a big difference in both comfort and cost. At ARCO Heating & Cooling , we specialize in helping Missouri and Illinois homeowners find heating solutions that work smarter—not harder—through professional installation services and expert guidance. Why Energy Efficiency Matters in Winter Heating accounts for a major portion of winter energy bills, especially if your system is more than 10–15 years old. An energy-efficient heating solution not only lowers monthly utility costs but also reduces wear and tear on your HVAC system and shrinks your environmental footprint. When you choose the right system, you’re choosing better air quality, more consistent indoor temperatures, and long-term savings. Top Energy-Efficient Heating Systems for Your Home 1. Heat Pumps One of the most efficient systems available, heat pumps transfer heat instead of generating it. This makes them up to three times more efficient than traditional electric heating systems. They also double as an air conditioner in the summer! 2. High-Efficiency Furnaces Modern gas furnaces with an AFUE (Annual Fuel Utilization Efficiency) rating of 90% or higher provide powerful heating while minimizing energy waste. These units convert nearly all the fuel they consume directly into heat for your home. 3. Ductless Mini-Split Systems Ideal for smaller spaces or additions, ductless mini-splits allow you to heat specific areas independently. This zoning ability reduces energy waste and gives you more control over your home’s comfort. 4. Smart Thermostats Paired with a new system, a smart thermostat helps maximize efficiency by learning your routines and adjusting the temperature accordingly—even when you’re away. Is It Time to Upgrade? If you’ve noticed higher heating bills, uneven temperatures, strange noises, or frequent repairs, it might be time to consider an upgrade. ARCO Heating & Cooling offers expert consultations to assess your current system and recommend the most efficient options tailored to your home and budget. ARCO Heating & Cooling: Your Local Heating Experts With decades of experience serving homeowners across Missouri and Illinois, ARCO Heating & Cooling is your trusted partner for efficient, reliable heating solutions. We offer: ✅ Free estimates on new heating systems ✅ Professional installation of top-tier brands ✅ Energy-efficient upgrades and heat pump options ✅ Financing plans to fit your needs ✅ Ongoing maintenance services to extend system life Make This Winter Your Most Comfortable One Yet Don’t wait for the first frost to find out your heater can’t keep up. Let ARCO Heating & Cooling help you stay warm, reduce energy costs, and upgrade to a system you can count on all winter long. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your free consultation or learn more about our energy-efficient heating installations.
A person is holding a dirty air filter in their hands.
By ARCO HEATING AND COOLING September 4, 2025
As the leaves begin to change and temperatures start to dip, it’s the perfect time to prepare your HVAC system for the cooler months ahead. Fall HVAC maintenance ensures your home remains warm, energy-efficient, and safe throughout the season. With ARCO Heating & Cooling ’s seasonal maintenance services, homeowners in Missouri and Illinois can enjoy peace of mind knowing their systems are ready for anything. Why Fall Maintenance Matters Your HVAC system has worked hard all summer, and fall is the ideal season to address any wear and tear. Routine maintenance improves performance, extends the life of your equipment, and can prevent costly breakdowns during the coldest days of winter. Fall HVAC Maintenance Checklist Here’s a quick checklist to help prepare your HVAC system: 1. Replace Air Filters Clogged filters restrict airflow and force your system to work harder. Swap them out for clean ones to maintain efficiency and indoor air quality. 2. Inspect and Clean Vents Blocked or dirty vents reduce circulation. Make sure all registers are unobstructed and clean to ensure warm air can flow freely. 3. Check the Thermostat Make sure your thermostat is working properly and consider upgrading to a programmable or smart model for better energy control. 4. Test the Heating System Run your heater before temperatures drop too low. Strange noises or a lack of warm air could indicate underlying issues that need attention. 5. Schedule Professional Inspection An expert technician can check for potential problems, clean internal components, and make sure everything is functioning safely and efficiently. ARCO Heating & Cooling’s Seasonal HVAC Services ARCO Heating & Cooling offers comprehensive fall HVAC maintenance packages tailored to your home’s specific needs. Our trained technicians will inspect, clean, and tune up your system to ensure it’s operating at peak performance. Whether you're in St. Louis or the surrounding areas, we make seasonal maintenance simple and stress-free. Don’t Wait for the Chill to Hit Preventive maintenance can save you from surprise repairs and high utility bills. Get ahead of the fall chill by booking your HVAC tune-up now. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your fall maintenance service and keep your home cozy all season long!
A white humidifier is sitting on a wooden floor in a room.
By ARCO HEATING AND COOLING August 21, 2025
Understanding Humidity and How It Affects Your HVAC System When it comes to home comfort, temperature isn't the only factor at play. Humidity levels can significantly impact how your home feels, how well your HVAC system performs, and even your monthly energy bills. In this blog, we’ll dive into how humidity affects indoor comfort and introduce smart solutions from Arco Heating & Cooling that keep your home balanced year-round. Why Humidity Matters - More Than Just Moisture Humidity is the amount of water vapor in the air. When it's too high, your home can feel sticky, warm, and uncomfortable. When it's too low, it can lead to dry skin, irritated sinuses, and even damage to wood furnishings. Maintaining optimal indoor humidity (ideally between 30%–50%) is key for both comfort and health. How High Humidity Affects HVAC Performance System Strain and Reduced Efficiency Excess moisture forces your air conditioning system to work overtime. Your A/C isn’t just cooling the air—it’s also trying to remove water vapor. This added workload can: Increase energy consumption Cause uneven cooling Lead to premature wear and tear on components Mold and Mildew Risks High humidity creates an ideal environment for mold growth in ducts, vents, and other HVAC components. This can compromise indoor air quality and trigger allergies or respiratory issues. Low Humidity Isn’t Great Either Winter Woes In colder months, humidity levels naturally drop. When your HVAC system heats the air, it can become even drier, leading to: Cracked skin and lips Dry eyes and sore throats Static electricity Warped wood floors or furniture Signs Your Home Has Humidity Issues Foggy windows Musty odors Frequent allergy symptoms Hot or cold spots throughout the house Overworked HVAC system If you’re noticing these signs, it may be time to consider humidity control solutions. Arco Heating & Cooling’s Humidity Control Solutions Tailored for Missouri and Illinois Homes At Arco Heating & Cooling, we understand the regional climate challenges. That’s why we offer humidity control solutions designed to work with your existing HVAC system: Whole-home dehumidifiers : Remove excess moisture during hot, humid summers. Humidifiers : Add moisture to dry winter air for improved comfort and health. Smart thermostats : Monitor and manage humidity levels automatically. System integration : We ensure any humidity solution works seamlessly with your current setup. Our expert technicians will help you assess your home’s needs and install the right solution for year-round comfort. Breathe Easier and Feel Better—All Year Long Managing humidity isn’t just about comfort—it’s about efficiency, health, and protecting your home. Whether you need help with high summer humidity or dry winter air, Arco Heating & Cooling has the tools and expertise to help. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule a consultation and learn how our humidity control solutions can transform your home’s comfort.
An air conditioner is sitting outside of a mobile home  next to a window.
By ARCO HEATING AND COOLING August 5, 2025
Is Your A/C on Its Last Legs? Here’s How to Know Your air conditioner is one of the most important appliances in your home—especially during sweltering summers. But like any machine, it wears out over time. Paying attention to warning signs can save you from a complete breakdown on the hottest day of the year and help you plan for a seamless replacement. In this guide, we’ll cover the key indicators that it’s time to replace your air conditioner and how Arco Heating & Cooling can make the process easy. 1. Your Unit Is Over 10–15 Years Old - Why Age Matters Most A/C systems have a lifespan of around 10 to 15 years. If your unit is approaching or past this age range, its efficiency and reliability drop significantly—and replacement parts become harder to find. 2. Rising Energy Bills Despite Similar Use -When Efficiency Falls Off Have you noticed a steady increase in your cooling costs? A failing compressor, refrigerant leaks, or worn-out coils can force your air conditioner to run longer and work harder, driving up your monthly bills. 3. Frequent Breakdowns and Repair Costs - The Repair vs. Replacement Math Paying for repairs every few months adds up quickly. If repair costs exceed half the price of a new system, replacement is usually the smarter choice. A new, energy-efficient unit will also cut down on future service calls. 4. Inconsistent Cooling and Hot Spots - Uneven Comfort Does one room feel freezing while another barely cools off? Inconsistent airflow often indicates that your system is struggling to maintain balanced temperatures—a sign that major components are failing. 5. Strange Noises and Unpleasant Odors - When Something Smells (or Sounds) Off Banging, grinding, or squealing noises can signal mechanical issues, while musty or burning odors may point to mold growth or electrical problems. Both are reasons to consider replacement before a safety hazard arises. 6. Refrigerant Leaks - Environmental and Performance Concerns Older units use R-22 refrigerant (Freon), which is being phased out due to environmental regulations. If your system leaks, retrofitting it can be expensive—and often less cost-effective than installing a new, eco-friendly unit. 7. Outdated Technology and Lack of Smart Features - Modern Comfort and Savings New air conditioners come with variable-speed compressors, advanced airflow designs, and smart thermostats for precise temperature control. Upgrading can offer better comfort, quieter operation, and integration with home automation systems. Seamless Replacement with Arco Heating & Cooling Replacing your air conditioner doesn’t have to be stressful. At Arco Heating & Cooling, we offer: Free in-home consultations to assess your space and recommend the right-size unit Professional removal of your old system and responsible disposal Expert installation of high-efficiency, ENERGY STAR®-rated A/C units Ongoing maintenance plans to keep your new system running at peak performance Don’t Wait Until It’s Too Late If you recognize any of these warning signs, now is the time to plan your air conditioner replacement. Avoid mid-season rushes, stay comfortable all summer, and lock in the latest energy-saving technology. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your free consultation and take the first step toward a cooler, more efficient home!
A person is sitting at a table with a piggy bank and a calculator.
By ARCO HEATING AND COOLING July 17, 2025
Keep Your System Running Smoothly—and Your Wallet Happy Routine HVAC maintenance isn’t just about comfort—it’s one of the smartest ways to cut costs on your energy bills and avoid expensive emergency repairs. By investing in regular tune-ups, you’ll ensure your heating and cooling system operates at peak efficiency, lasts longer, and keeps you worry-free all year long. 1. Prevent Costly Breakdowns What happens without maintenance: Dusty coils, worn belts, and loose electrical connections place extra strain on your system. Over time, minor issues can snowball into major failures that require costly parts or even a full system replacement. Your savings: A simple annual inspection can catch and fix minor wear before it turns into a breakdown—potentially saving you thousands in emergency repair bills. 2. Improve Energy Efficiency What happens without maintenance: Clogged filters or dirty coils make your system work harder, driving up energy consumption. According to industry studies, a neglected HVAC system can lose up to 20% of its original efficiency. Your savings: Clean filters and properly calibrated components can reduce your energy use by 5–15%, translating into noticeable monthly savings on your utility bills. 3. Extend Equipment Lifespan What happens without maintenance: Continuous strain speeds up wear on motors, compressors, and other key parts. A well-maintained system can often last 2–4 years longer than one that’s ignored. Your savings: Delaying a premature replacement by even a year means avoiding a $4,000–$7,000 equipment purchase—money that stays in your pocket. 4. Maintain Manufacturer Warranties What happens without maintenance: Most HVAC warranties require proof of annual professional maintenance . Skipping service visits can void your coverage, leaving you on the hook for the full cost of any repairs. Your savings: By sticking to a regular maintenance schedule, you preserve your warranty protection—ensuring that if something does go wrong, you’ll pay far less out of pocket. Discover ARCO Heating & Cooling’s Maintenance Plans At ARCO Heating & Cooling , we offer tailored maintenance plans designed to fit every budget and schedule: Silver Plan: Annual inspection, filter replacement, and priority scheduling. Gold Plan: Bi-annual inspections, filter changes, coil cleaning, and 10% parts discount. Platinum Plan: Quarterly service visits, full system diagnostics, priority emergency response, and a 15% parts discount. Each plan includes detailed reports and recommendations—so you always know exactly how your system is performing. Ready to Save on Your HVAC Costs? Don’t wait for a breakdown or a sky-high energy bill to remind you—schedule your HVAC maintenance today! As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling at (636) 389-6471 to learn more about our maintenance plans and keep your system—and your budget—in peak condition.
A man and a woman are sitting on a couch in front of a fan.
By ARCO HEATING AND COOLING July 1, 2025
Beat the Heat: Get Your A/C Ready for Extreme Temperatures When summer heat rises, your HVAC system becomes the heart of your home’s comfort. Without proper preparation, rising temps can overwhelm older or neglected systems—leading to breakdowns, higher energy bills, and discomfort. That’s why now is the perfect time to get ahead of the heat with a professional inspection from Arco Heating & Cooling . Why Preparing Your HVAC System Matters Heatwaves can put intense strain on air conditioning units, especially if they haven’t been serviced recently. A well-maintained system will: Run more efficiently Cool your home evenly Avoid mid-summer breakdowns Extend the lifespan of your equipment Tips to Prepare Your A/C for Summer 1. Schedule a Professional Inspection Annual inspections from HVAC professionals ensure your system is clean, safe, and operating at peak performance. Our Arco technicians check refrigerant levels, electrical connections, filters, coils, and more. 2. Change or Clean Air Filters Clogged filters reduce airflow and make your system work harder. Replace filters monthly during peak summer months for optimal efficiency and indoor air quality. 3. Clear the Area Around Your Outdoor Unit Remove leaves, debris, or overgrown vegetation around your condenser. This helps the unit release heat more effectively and reduces the risk of overheating. 4. Seal Leaky Ducts and Insulate Cool air can escape through poorly sealed ducts, wasting energy and making your system work harder. Consider duct sealing and insulation upgrades if you notice uneven temperatures. 5. Upgrade Your Thermostat Smart thermostats allow for programmable temperature settings, helping you stay cool while saving energy—especially during heatwaves. Why Homeowners Trust Arco Heating & Cooling We’ve helped families across Missouri and Illinois stay comfortable through even the hottest summers. Our certified HVAC technicians: Offer detailed inspections and honest recommendations Provide fast, reliable service Install energy-efficient cooling systems when needed Stay Cool All Summer Long Don’t wait for the first triple-digit day to realize your system isn’t ready. Be proactive and keep your home comfortable, safe, and energy-efficient. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your pre-summer HVAC inspection!
An air conditioner is sitting on the side of a mobile home next to a window.
By ARCO HEATING AND COOLING June 19, 2025
Stay Cool and Save Money with Modern Air Conditioning When summer hits Missouri and Illinois , your air conditioner becomes the hardest-working appliance in your home. But if your current A/C system is more than 10 years old, it might be costing you more than you think. Upgrading to a high-efficiency A/C system can significantly reduce your energy bills while delivering better comfort. At Arco Heating & Cooling , we specialize in energy-saving air conditioning installations that keep your home cool and efficient. Why Upgrade to a High-Efficiency A/C Unit? 1. Lower Energy Bills High-efficiency A/C systems use advanced compressors, variable-speed fans, and smart thermostats to cool your home using less electricity. Many homeowners see a 20–40% drop in energy costs after upgrading. 2. Improved Indoor Comfort Modern systems offer more consistent temperatures, better humidity control, and quieter operation. Say goodbye to hot spots and noisy units. 3. Eco-Friendly Performance Today’s high-efficiency models are designed to reduce carbon emissions, using environmentally friendly refrigerants and technology that meets ENERGY STAR® standards. 4. Smart Features & Connectivity Many systems integrate with smart home technology , giving you remote control through your smartphone and personalized cooling schedules. 5. Rebates & Incentives Upgrading may qualify you for utility rebates, tax credits, or manufacturer incentives—making the investment even more affordable. Signs It's Time to Upgrade Your A/C Your system is over 10–15 years old Frequent breakdowns and repair costs Uneven cooling throughout the home Rising energy bills Loud or inefficient operation Trust Arco Heating & Cooling with Your A/C Upgrade We make the upgrade process easy: Free consultations and system recommendations Licensed, experienced installation technicians High-quality equipment from trusted brands Ongoing support and maintenance options Let’s Upgrade Your Comfort Ready to save money and beat the summer heat? A high-efficiency A/C system can make a world of difference in your comfort and energy use. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your free consultation and get started on your A/C upgrade!
A mini split white air conditioner are sitting next to each other on a white background.
By ARCO HEATING AND COOLING June 3, 2025
Flexible Comfort for Every Room and Every Season Living in Missouri and Illinois means experiencing all four seasons—and sometimes all in the same week! From hot, humid summers to icy winters, homeowners need heating and cooling systems that can adapt to changing weather. That’s where mini-split systems shine. At Arco Heating & Cooling, we specialize in mini-split installations tailored to the unique needs of homes across the Midwest. What Is a Mini-Split System? A mini-split system is a type of ductless HVAC that provides targeted heating and cooling to individual rooms or zones in your home. Unlike central systems that push air through ducts, mini-splits use small, wall-mounted indoor units connected to an outdoor compressor. Benefits of Mini-Split Systems 1. Zoned Comfort Customize temperatures for different rooms or areas. No more fighting over the thermostat or wasting energy in unused spaces. 2. Energy Efficiency Mini-splits avoid the energy losses associated with ductwork, making them more efficient than traditional systems. Many models are ENERGY STAR® certified. 3. Year-Round Climate Control With both heating and cooling capabilities, mini-splits are perfect for Missouri and Illinois’ unpredictable weather patterns. 4. Easy Installation No ductwork? No problem. Mini-splits are ideal for older homes, additions, basements, and garages. 5. Quiet Operation Mini-splits are known for being whisper-quiet, making them a great option for bedrooms, nurseries, or home offices. Why Arco Heating & Cooling? We bring years of experience installing and servicing mini-split systems throughout Missouri and Illinois. Our technicians will: Recommend the best unit for your space and needs Provide professional, clean installation Help you understand how to use your system for maximum comfort and efficiency Get Ready for Comfort—No Matter the Season Don’t settle for uneven temperatures or high energy bills. Whether you're renovating or simply looking for more control over your indoor climate, mini-splits are a smart investment. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule a consultation and discover how a mini-split system can transform your home's comfort!
A person is pressing a button on a thermostat that is set to 70 degrees
By ARCO HEATING AND COOLING May 22, 2025
Upgrade You r Comfort and Savings with Smart Thermostat Technology Your thermostat plays a much bigger role in your home’s energy efficiency than you might think. Whether you’re heating your home in the winter or cooling it in the summer, how and when your HVAC system runs often comes down to thermostat control. At Arco Heating & Cooling , we help homeowners boost efficiency with expert thermostat installation services —including the latest in smart thermostat technology. Why Thermostats Matter Your thermostat acts as the brain of your heating and cooling system. When it's outdated or inefficient, it can lead to: Inconsistent temperatures Increased energy use Higher monthly utility bills On the other hand, upgrading to a modern thermostat—especially a smart thermostat—can significantly improve your system’s performance. Benefits of Smart Thermostats 1. Energy Savings Smart thermostats learn your habits and adjust temperatures automatically for optimal efficiency, helping you save up to 10–15% on heating and cooling costs. 2. Remote Access Use your smartphone to control your home’s temperature from anywhere. This is especially useful for busy families, travelers, or anyone who forgets to adjust the thermostat before leaving. 3. Customized Scheduling Set detailed schedules for different times of day or days of the week to avoid wasting energy when no one’s home. 4. Energy Reports Many models provide insight into your energy use, showing where you can make adjustments to save even more. 5. Integration with Smart Home Systems Smart thermostats can connect to Alexa, Google Home, and other smart devices for full-home automation. Arco Heating & Cooling's Thermostat Installation Services We offer: Expert recommendations for the best smart thermostat to fit your HVAC system Professional installation to ensure correct setup and compatibility Guidance on app setup, programming, and usage Make the Smart Move Today Don't let an outdated thermostat cost you comfort and cash. Upgrade to a smart thermostat and take control of your energy use. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area, including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your thermostat installation and start saving energy the smart way!
A man with glasses is covering his nose in a living room. A bad smell.
By ARCO HEVAC May 2, 2025
Identifying HVAC Odors in Your Home—and When to Take Action Unusual smells in your home can be alarming—especially when they come from your heating and cooling system. Some odors are harmless, but others can signal serious issues. At Arco Heating & Cooling, we help homeowners identify HVAC-related smells and determine when it's time to worry—and take action. Common HVAC Smells and What They Mean 1. Burning Dust Smells like: Burning or dusty odor When it happens: Usually when turning on your heat for the first time in the season Should you worry? Not usually. It’s common and usually goes away quickly as dust burns off your heating elements. 2. Electrical or Burning Plastic Smell Smells like : Hot wires, melting plastic When it happens: While the system is running Should you worry? Yes. This may signal overheating parts, frayed wires, or a serious electrical issue. Turn off the system and call a professional immediately. 3. Rotten Egg or Sulfur Smell Smells like: Sulfur, rotten eggs When it happens: At any time Should you worry? Absolutely. This could indicate a natural gas leak. Leave your home immediately and contact your gas provider and HVAC technician. 4. Musty or Moldy Smell Smells like: Damp basement, mildew When it happens: Often when the AC runs Should you worry? Yes. This could be a sign of mold or mildew in your ducts or system. Not only can this affect indoor air quality, but it can also impact your family’s health. 5. Sewage or Dead Animal Smell Smells like: Foul, decaying odor When it happens: Sporadically or continuously Should you worry? Yes. You might have a pest problem or a sewage backup near your HVAC system. Call a professional to inspect it. What To Do If You Notice a Strange Smell Don’t ignore it . Even if the smell seems minor, it could be a warning sign. Turn off your system if the smell is electrical, smoky, or foul. Call a licensed HVAC professional like Arco Heating & Cooling to diagnose the issue safely and quickly. Trust Arco Heating & Cooling to Sniff Out the Problem Our team has the tools and experience to diagnose strange odors and fix HVAC issues fast. Whether it’s a routine cleaning, an electrical fix, or system replacement, we’re here to help keep your home safe and comfortable. As a trusted heating and cooling contractor based in St. Charles, MO , we proudly serve the entire St. Louis metropolitan area , including both Missouri and Illinois. Call ARCO Heating & Cooling today at (636) 389-6471 to schedule your inspection and get peace of mind!
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