5 Warning Signs Your Furnace Is About to Break Down

Few things are more frustrating than waking up on a freezing winter morning to find that your furnace has stopped working. A furnace breakdown is not just inconvenient; it can also lead to costly emergency repairs or even a full system replacement.

The good news is that most furnaces give off warning signs before they completely fail. By recognizing these signs early, you can avoid sudden breakdowns, stay warm all winter, and save money on repairs. If you notice any of the following five warning signs, it’s time to call a professional HVAC technician for an inspection before a minor issue turns into a major problem.

1. Your Furnace is Blowing Cold Air

If your furnace is running, but your home still feels chilly, something is definitely wrong. Furnaces should consistently provide warm air when needed.

Possible Causes of Cold Air from Your Furnace:

Dirty air filters blocking proper airflow
Pilot light or ignition system failure
Thermostat malfunctions preventing proper heating
Ductwork leaks allowing warm air to escape

Before assuming the worst, check your thermostat settings and replace your air filter. If the problem persists, your furnace may need professional attention to diagnose and fix the issue.

2. Strange Noises Coming from Your Furnace

Your furnace should operate quietly in the background. If you start hearing banging, rattling, squealing, or grinding noises, it’s a clear sign that something is wrong.

Common Furnace Noises and What They Mean:

Banging or booming – This could indicate a delayed ignition or dirty burners, which can be dangerous.
Squealing or screeching – Often caused by a worn-out belt or motor bearings that need lubrication.
Rattling or vibrating – Loose panels or internal components may be the issue.
Clicking sounds – A faulty ignition system or a malfunctioning gas valve could be the cause.

Ignoring these sounds can lead to serious damage or even a complete system failure. If you hear unusual noises, schedule an inspection with a heating professional as soon as possible.

3. Your Energy Bills Are Higher Than Usual

If your heating costs have suddenly spiked without a change in outdoor temperatures, your furnace may be struggling to operate efficiently.

Why Your Furnace is Driving Up Your Energy Bills:

Aging system – Older furnaces lose efficiency over time.
Clogged air filters – A dirty filter makes your furnace work harder, using more energy.
Leaky ductwork – Heated air escaping through cracks forces your system to run longer.
Failing components – A worn-out blower motor or malfunctioning thermostat can cause excessive energy consumption.

Higher energy bills are often the first warning sign that your furnace needs maintenance or a potential upgrade. Addressing the issue early can save you money in the long run.

4. Your Furnace is Short Cycling (Turning On and Off Frequently)

If your furnace turns on and off repeatedly without fully heating your home, this is known as short cycling. This behavior can lead to premature wear and tear on your system, reducing its lifespan.

Possible Causes of Short Cycling:

Overheating – A dirty filter or blocked airflow can cause the system to shut down to prevent damage.
Thermostat issues – A faulty thermostat may not be reading temperatures correctly.
Improper furnace sizing – If your furnace is too large for your home, it will heat up too quickly and shut off before completing a full cycle.

Short cycling increases energy costs and puts unnecessary stress on your furnace, leading to more frequent repairs. A professional HVAC inspection can identify and fix the underlying issue.

5. Unusual Smells or Poor Air Quality

A properly functioning furnace should not produce strange odors. If you notice burning, musty, or gas-like smells, it could indicate a serious problem.

Common Furnace Smells and Their Causes:

Burning smell – This can happen when dust burns off after the first use of the season, but if the smell persists, it could be a sign of electrical issues.
Musty odor – Moisture buildup or mold growth in your ductwork may be the culprit.
Gas smell (like rotten eggs) – This is an emergency situation. It could indicate a gas leak, and you should turn off your furnace immediately and call your gas company.

Additionally, if you notice more dust, dry air, or increased allergy symptoms, your furnace may not be filtering air properly. Replacing air filters regularly and scheduling professional maintenance can improve air quality.

When to Call ARCO Heating & Cooling for Furnace Repair

If you’re experiencing any of these warning signs, your furnace could be at risk of breaking down. The sooner you address the issue, the more likely you are to avoid costly emergency repairs or system failure.

Call a Professional If:

Your furnace is blowing cold air instead of heat
You hear unusual noises like banging, rattling, or squealing
Your energy bills have increased suddenly
Your furnace keeps turning on and off
You notice burning, musty, or gas-like odors

Regular furnace maintenance can extend the life of your system, improve efficiency, and prevent breakdowns. The best way to ensure your furnace is working properly is to schedule a professional inspection before winter is in full swing.

Schedule Your Furnace Inspection with ARCO Heating & Cooling Today

Don’t wait for a complete furnace breakdown before taking action. If you’ve noticed any of these warning signs, contact ARCO Heating & Cooling to schedule an inspection and get your heating system back on track.

Call Now to Schedule Your Furnace Maintenance

📞 (636) 259-3961

Stay warm, save money, and avoid unexpected furnace failures this winter with expert HVAC service from ARCO Heating & Cooling.

< Older Post

Newer Post >

A woman is sitting on a couch in a living room holding a HVAC remote control.

The Importance of Indoor Air Quality in Transitional Seasons

By ARCO HEATING AND COOLING • April 25, 2025

How Seasonal Shifts Impact the Air You Breathe When spring turns into summer or fall shifts into winter, your home’s indoor air quality (IAQ) can change dramatically. These transitional seasons bring fluctuating temperatures, increased allergens, and different HVAC usage patterns—all of which can affect the health and comfort of your indoor environment. At Arco Heating & Cooling , we’re here to help you understand these shifts and keep your home’s air clean and comfortable year-round. What Happens to Indoor Air Quality in Transitional Seasons? More Time Indoors, More Exposure As temperatures become unpredictable, people tend to spend more time inside. While this keeps you comfortable, it also means you’re breathing indoor air more frequently—and if that air is filled with dust, pollen, or other irritants, it can take a toll on your health. Allergens Are on the Move Spring and fall are peak seasons for pollen, mold spores, and other allergens. Without proper filtration and ventilation, these particles can easily find their way indoors and linger in your HVAC system. HVAC Systems Kick Into Gear Transitional seasons often involve switching between heating and cooling. This inconsistent use of your HVAC system can lead to dust buildup in filters and ducts, impacting air quality and system efficiency. Signs of Poor Indoor Air Quality Persistent allergy symptoms Dust buildup near vents Musty or stale indoor smells Dry skin or throat irritation Excess humidity or dryness If you're experiencing any of these, it may be time to improve your indoor air quality. Arco Heating & Cooling’s Indoor Air Quality Solutions Tailored to Missouri and Illinois Homes We offer a range of products and services designed to enhance IAQ throughout transitional seasons: Air purifiers : Capture and remove airborne particles including pollen, dust, and bacteria. Humidifiers and dehumidifiers : Balance humidity levels to prevent mold growth and dry air discomfort. HEPA filters : High-efficiency filters for cleaner, healthier air. Duct cleaning services : Eliminate built-up dust, mold, and debris in your ductwork. Smart HVAC controls : Automate air quality monitoring and adjustments for convenience and efficiency. Our expert team will assess your needs and recommend the right solution to improve your indoor air all year long. Breathe Better This Season—and Every Season Your home should be a safe, comfortable place, no matter the weather outside. By investing in indoor air quality solutions, you protect your health, enhance comfort, and improve HVAC efficiency. Let Arco Heating & Cooling help you transition smoothly into every new season. 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 indoor air quality consultation. Breathe easier with expert solutions tailored to your home.

A white air conditioner is hanging on a wall next to a window.

How to Choose the Right HVAC System for Your Home Size

By ARCO HEATING AND COOLING • April 25, 2025

Find the Perfect HVAC Fit for Your Home's Comfort and Efficiency Selecting the right HVAC system isn’t just about brand or features—it’s about choosing a unit that fits your home’s size and layout. An improperly sized system can lead to high energy bills, uneven temperatures, and unnecessary wear and tear. At Arco Heating & Cooling , we help you choose the perfect system for optimal performance and year-round comfort. Why HVAC System Size Matters An HVAC system that’s too large or too small can cause a variety of issues: Oversized systems short-cycle, leading to inefficient operation and uneven temperature control. Undersized systems run constantly, struggle to maintain comfort, and lead to higher energy usage and faster wear. Correct sizing ensures maximum efficiency, lower utility bills, and a longer-lasting system. Key Factors in HVAC Sizing 1. Square Footage of Your Home The size of your home is the most critical factor. HVAC systems are rated in BTUs (British Thermal Units), and each square foot of living space typically requires a certain number of BTUs. 2. Climate Zone Homes in colder or hotter climates require more powerful systems to maintain comfort. Missouri’s four-season weather means your HVAC system needs to handle both heating and cooling efficiently. 3. Home Layout and Insulation High ceilings, window placement, and insulation quality can impact your home’s heating and cooling needs. A well-insulated home may require a smaller unit than a drafty one. 4. Number of Occupants and Appliances More people and heat-generating appliances (like ovens) can affect your home's internal temperature and should be factored into system sizing. Let Arco Heating & Cooling Help Choosing the right HVAC system doesn't have to be a guessing game. Arco Heating & Cooling offers expert consultation services to: Evaluate your home’s size, layout, and needs. Recommend HVAC systems based on BTU requirements and efficiency ratings. Provide professional installation and ongoing maintenance for peak performance. Get the Right System, the First Time Don’t risk investing in the wrong HVAC setup. Let the experts at Arco Heating & Cooling guide you toward a system that fits your home, budget, and comfort goals perfectly. 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 HVAC consultation and make the smart choice for your home!