Why a Furnace Blows Cold Air - Common Causes Explained

If your furnace is blowing cold air, your house will get pretty uncomfortable fast. Many Jurupa Valley residents run into this problem, particularly when they first turn on their heat after not using it for a while.

At Inland Empire Comfort, we provide furnace repair in Jurupa Valley and understand the ins and outs of why a furnace blows cold air. We'll determine exactly what's wrong and get your heat working again.

Keep reading to learn what might be going wrong with your system and how to get your home cozy again.

Possible Reasons Your Furnace Is Blowing Cold Air

When you turn on your gas furnace, it doesn't blow hot air right away. First, the burners light up. The fan waits a bit before starting and will need to push out all the cold air sitting in your ducts.

Don't worry if you feel cold air coming out at first—that's just how furnaces work. But if it stays cold after a few minutes, something is probably not right.

A Faulty Thermostat

A defective thermostat can blow cold air when thermostat settings are wrong: either stuck on "cool" instead of "heat," running on "fan" instead of "auto," or set too low. Sometimes, broken wiring between the thermostat and the furnace causes constant cold airflow.

You want to set the temperature above 68°F, like 72°F, to trigger heat. Sometimes, faulty thermostat wiring may prevent communication with the furnace, requiring you to call an HVAC professional to diagnose the issue.

Dirty Air Filter

When the filter gets clogged with dust and debris, it blocks the normal flow of air into the furnace. Without enough air flowing through, the furnace can't properly heat what little air makes it past the filter. This triggers safety switches that shut off the burners to prevent damage from overheating.

As a result, your furnace just pushes around room-temperature air without warming it up. Even though you have the heat on, you'll stay cold because the blocked airflow stops the furnace from doing its job of heating the air. This is a common reason why a furnace blows cold air.

Blocked Airflow

Small or blocked ducts mean less air flows in, so your furnace struggles to heat what little air it gets. Clogged filters or poorly sized ductwork are common culprits.

The result is that your furnace gives up and blows cold air instead of keeping your home cozy.

Circuit Control Board Malfunction

If the control board breaks, the furnace can't run its basic functions properly. The board might still run the blower fan but fail to ignite the burners, resulting in cold air blowing through your vents.

This typically happens when dirt builds up on the board, or water from a leak damages its electrical components. You need to act quickly to prevent complete heating failure.

Leaky Ducts

Leaky ducts are like throwing away money and comfort. When your furnace pushes heated air through damaged ducts, up to 30% of that warmth escapes into unused spaces like crawl spaces and walls. Meanwhile, holes in the ductwork suck in cold air from unheated areas.

By the time air reaches your rooms, it's a disappointing mix of heated and cold air. This explains why you might feel chilly even with the heat running.

A Damper Issue

If your ducts have closed or stuck dampers, warm air can't get to parts of your house. Your furnace cranks up to compensate, working overtime to heat those cold spots. When it works too hard, it overheats and automatically switches to cold air to protect itself from damage.

This happens pretty often—the furnace basically hits the brakes to prevent further damage. A simple damper adjustment might be all you need to fix the issue.

Pilot Light or Ignition Issues

If your furnace's ignition system fails, you'll get cold air because there's no flame to heat it. In modern furnaces, a dirty flame detector can shut off the heat while the blower keeps running.

Older furnaces with pilot lights can have similar issues—if debris blocks the pilot or it burns yellow instead of blue, you won't get proper heating. Either way, no flame means cold air, which is a common reason why a furnace blows cold air. Without proper ignition, the system can't generate heat, leaving you with chilly airflow.

Lack of Fuel (Gas Furnaces)

When your furnace doesn't get enough gas, it can't create the flame needed for heating. Just like your car needs fuel to run, your furnace needs gas.

If there's a problem with the gas valve or you're running low on propane, the furnace will still blow air—it just won't be heated. You can spot this issue if your other gas appliances aren't working either.

Triggered Safety Mode

When your furnace overheats, its safety switch kicks in to prevent damage. This causes it to blow cold air until things cool down, which explains why you might notice your furnace alternating between hot and cold air output; it’s actually protecting itself.

Faulty Main Limit Switch

A faulty limit switch may incorrectly tell your furnace it's overheating even when it's not. This false alarm triggers the safety shutdown, stopping the heating cycle. Instead of producing warm air as it should, your furnace just blows cold air until a professional replaces the broken switch.

Heat Exchanger Problems

A cracked heat exchanger is a dangerous furnace problem that can make your home's air stay cold. When this critical part breaks, it can't properly heat the air flowing through your furnace.

Worse yet, deadly carbon monoxide gas can leak into your home's air. You need immediate professional help if this happens.

Schedule Reliable Furnace Repair

Is your furnace blowing cold air? Time for annual furnace maintenance? Our technicians at Inland Empire Comfort will determine what's wrong and restore your comfort. We'll explain exactly what needs to be done and get your heat back up and running fast.

We fix furnaces—both urgent breakdowns and regular upkeep. Big job or small, we'll do the job right. Call Inland Empire Comfort when your furnace needs repair or for more information on why a furnace blows cold air.

< Older Post

Newer Post >

You might also like

Inland Empire Comfort

A Complete Guide to Choosing the Best AC Unit for Your Riverside, CA Home

By SEOCH • November 26, 2025

Choosing the best AC unit for your Riverside, CA home begins with understanding your specific cooling needs. Start by measuring your space and taking local heat levels into account. There are a variety of options available, ranging from central air systems to window units. It's crucial to pay attention to efficiency ratings and cooling capacity to ensure optimal performance. Features like noise level and smart thermostats can significantly enhance your comfort. Additionally, don't forget to factor in installation and maintenance costs. With the right information, you can decide to keep your home cool during those scorching summers. For more insights and expert advice, you're in good hands with trusted professionals in the area. Understanding Your Cooling Needs How do you determine the right air conditioning unit for your home? Start by evaluating the size of your living space. Measure the square footage to ensure you select an AC unit that can efficiently cool your entire area. Next, consider your local climate. In Riverside, CA, where summers can be scorching, you'll need a unit capable of handling higher temperatures. Think about your family's lifestyle as well. Do you have pets or allergies? If so, it may be beneficial to choose an AC with advanced filtration systems. Additionally, keep energy efficiency in mind. Look for units with high SEER ratings, as they can save you money on utility bills. Finally, establish a budget. Striking a good balance between upfront costs and long-term savings will serve you well. Engaging with a professional team for air conditioning servicing can also provide valuable insights tailored to your specific needs. Types of AC Units Available Once you've assessed your cooling needs, it's time to explore the various types of AC units available through Inland Empire Comfort. You have several options to evaluate. Central air conditioning systems are ideal for whole-home cooling, providing consistent comfort throughout your space. If you're looking for flexibility, ductless mini-split systems are perfect for homes without existing ductwork, allowing you to cool individual rooms efficiently. For smaller spaces, window units offer an affordable solution, while portable air conditioners can be easily moved from room to room as needed. If you're environmentally conscious, contemplate geothermal units, which utilize the earth's temperature for cooling and heating, notably reducing energy costs. Additionally, consider the benefits of professional Riverside AC replacements to ensure you select the most efficient model for your home. Each type has its pros and cons, so think about your home's layout, your budget, and your specific cooling requirements. This choice will greatly impact your comfort and energy efficiency in the long run, making it essential to consider the solutions provided by Inland Empire Comfort. Key Features to Consider When selecting the ideal AC unit for your home, it's essential to consider key features that can enhance your comfort and efficiency. First and foremost, evaluate the cooling capacity, measured in BTUs, as this determines how effectively the unit can cool your space. Choosing an AC that aligns with your home's size is crucial for optimal performance. Additionally, consider the noise level; quieter units can significantly impact your comfort, particularly during those sweltering summer nights. It's also worthwhile to examine the type of thermostat available, especially if it includes smart capabilities for convenient temperature control. Another important feature to assess is the air filtration system. High-quality filters can greatly improve indoor air quality, which is vital for your health. Lastly, pay attention to the warranty; a longer warranty often reflects a manufacturer's confidence in their product, giving you added peace of mind. Furthermore, ensuring your new AC unit is compatible with emergency AC repair services can provide peace of mind in case of unexpected breakdowns. Energy Efficiency and Cost Considerations Energy efficiency and cost considerations are crucial when selecting an AC unit. Look for units with high Seasonal Energy Efficiency Ratios (SEER), which indicate better performance and lower energy bills. While higher efficiency typically involves a greater upfront investment, reduced energy consumption leads to significant savings over time. It's also important to account for installation and maintenance costs, as these can vary between different models. Opting for a more efficient unit may even make you eligible for local rebates or tax incentives, helping to mitigate expenses further. Moreover, consider your home's size and insulation, as these factors significantly impact the AC unit's efficiency. Additionally, consult with licensed technicians to ensure proper installation and maintenance as these services can greatly enhance the longevity and performance of your new system. By balancing upfront costs with potential long-term savings, you can ensure that you select an AC unit that meets both your budget and comfort needs in Riverside, CA. Reaching out to professionals for tailored advice and options can provide valuable insight into the best choices for your specific situation. Professional Installation and Maintenance Tips Choosing the right AC unit is just the beginning; professional installation and regular maintenance are essential for ensuring optimal performance and longevity. When it's time for installation, consider hiring experts who guarantee precise setup, helping your unit operate efficiently from day one. Once your AC is installed, regular maintenance is crucial to avoid costly repairs. Schedule bi-annual check-ups, ideally in spring and fall, to ensure everything is running smoothly. During these visits, technicians can clean components, check refrigerant levels, and replace filters. Additionally, encourage good practices at home, such as keeping vents unobstructed and adjusting the thermostat for energy savings. Remember that minor issues can escalate quickly, so don't hesitate to call for repairs if you notice unusual noises or inconsistent cooling. Relying on professional services will keep your system in shape for years.

Top Benefits of Regular Air Conditioning Maintenance in Corona, CA

By SEOCH • November 26, 2025

Regular air conditioning maintenance in Corona, CA, significantly enhances energy efficiency and prolongs your system's lifespan. By ensuring filters are clean and components are inspected, you minimize the risk of breakdowns and improve indoor air quality. This proactive approach leads to cost savings on repairs and lower energy bills. Investing in regular maintenance is a smart choice for both your comfort and your budget. There are additional resources to explore for more insights on how to maximize these benefits for your home. Improved Energy Efficiency One of the key benefits of regular air conditioning maintenance is improved energy efficiency. Keeping your system in top shape means it doesn't have to work as hard to cool your home, resulting in lower energy bills. By scheduling routine check-ups, you ensure that vital components like filters and coils are clean and functioning well, allowing your unit to operate smoothly. With less strain on the system, your air conditioner uses less energy, which benefits your wallet and the environment. Additionally, maintenance helps spot minor issues before they escalate into major problems, preventing costly repairs in the future. A more efficient system not only provides consistent comfort but also extends the lifespan of your unit. Regular cleaning or replacement of filters and coils is essential for optimal performance. Trust in the expertise of Inland Empire Comfort to provide the personalized care you need to keep your air conditioner running efficiently, allowing you to relax and enjoy a cool home. Extended System Lifespan When you invest in regular air conditioning maintenance with Inland Empire Comfort, you enhance efficiency and greatly extend the lifespan of your system. By scheduling routine check-ups, professionals can identify and resolve minor issues before they escalate into major problems. This proactive approach means your air conditioner will run smoother, reducing wear and tear on essential components. Regular maintenance includes cleaning coils, checking refrigerant levels, and ensuring all parts are functioning effectively. These actions help prevent breakdowns and costly repairs, ultimately saving you money in the long run. Plus, a well-maintained system operates more reliably, giving you peace of mind during those hot summer months. Additionally, proper maintenance can significantly reduce repair costs and ensure your AC unit is ready for the warm weather ahead. Enhanced Indoor Air Quality Regular air conditioning maintenance from Inland Empire Comfort not only extends your system's lifespan but also significantly improves your indoor air quality. When you schedule regular check-ups, technicians clean and replace filters, which helps eliminate dust, allergens, and pollutants circulating in your home. This means you and your family can breathe fresher air, reducing allergy symptoms and respiratory issues. Moreover, a well-maintained system operates efficiently, preventing the buildup of mold and mildew in your ducts, which can compromise your health. Additionally, timely service can address refrigerant leaks that cause cooling difficulties and environmental hazards, ensuring your system runs optimally. You'll notice a significant difference in air quality, especially if you have pets or live in a dusty area. Trust in Inland Empire Comfort to keep your indoor environment healthy and comfortable. Reduced Risk of Breakdowns By scheduling routine maintenance with Inland Empire Comfort, you significantly decrease the likelihood of unexpected breakdowns in your air conditioning system. Regular check-ups allow for early detection of potential issues, ensuring your unit operates smoothly throughout the hot months. During these maintenance visits, skilled technicians inspect and tune-up your system, addressing any wear and tear that could lead to future failures. When components are cleaned and serviced, they function more efficiently, resulting in less strain on your system. This proactive approach enhances reliability and keeps your home comfortable when it matters most. Additionally, having confidence that your air conditioner is in peak condition provides peace of mind. Regular maintenance checks lower overall repair costs, contributing to a more economical and efficient heating operation for your home. Don't wait for a breakdown to disrupt your comfort; invest in routine maintenance and reap the benefits of a well-maintained air conditioning system. Cost Savings on Repairs and Energy Bills Investing in routine air conditioning maintenance with Inland Empire Comfort can lead to significant cost savings on both repairs and energy bills. By keeping your system in top shape, you're boosting its efficiency and preventing costly breakdowns. Regular check-ups catch potential issues before they escalate, saving you from expensive repairs down the line. Consider the benefits you'll enjoy: Lower energy bills thanks to improved efficiency. Fewer unexpected repair costs from minor issues caught early. Extended lifespan of your AC unit, maximizing your investment. Peace of mind knowing your system is running smoothly. Trust in the expertise of Inland Empire Comfort to keep your air conditioning system in optimal condition.

7 Telltale Signs It's Time to Replace Your AC in Colton, CA

By SEOCH • October 26, 2025

If your AC unit is over 10 years old, assessing whether it's time for a replacement is crucial. Rising energy bills often indicate inefficiency, and frequent repairs can quickly add up. You might also notice uneven cooling or unusual noises coming from the unit, which could signal underlying issues. Additionally, foul odors and excessive humidity can impact your health and overall comfort. If you recognize these signs, it may be wise to consider exploring your options for a more reliable system. Stay informed about these key warning signs! Your AC Is Over 10 Years Old If your AC is over 10 years old, it's time to start considering a replacement. As systems age, their efficiency tends to decline, leading to less effective cooling. You might notice that your home doesn't feel as comfortable as it used to, and you find yourself cranking up the thermostat more often. Additionally, older units can be prone to breakdowns, leaving you in the heat when you need relief the most. Replacing your AC now can save you from future headaches and costly repairs. Newer models cool better and come with advanced technology that enhances energy efficiency and environmental friendliness. Partnering with a trusted company can provide you with personalized options tailored to your needs and budget. Moreover, air conditioning units may require more repairs as they age, making a replacement a wise investment. With expert service and a dedication to customer satisfaction, you can enjoy a smoother transition to a more reliable and efficient cooling solution. Don't wait—consider a replacement today! Increased Energy Bills If your energy bills keep climbing, it might be a sign that your air conditioning system is struggling to keep up. An inefficient cooling performance can lead to higher utility expenses that drain your wallet. It's time to consider whether a new system from Inland Empire Comfort could save you money in the long run. Additionally, timely service can prevent further inefficiencies and extend the lifespan of your system. Rising Utility Expenses As energy costs continue to climb, you might notice your utility bills rising considerably each month. If your air conditioning system is older or not functioning efficiently, it could be the culprit behind those escalating expenses. An AC unit that struggles to keep your home cool often consumes more energy, leading to higher bills. You might find yourself cranking down the thermostat, only to see minimal results. If you're regularly checking your bills and they keep increasing, it's a sign your system may not be performing as it should. Addressing these rising utility expenses now can save you money in the long run. Consider consulting a professional from Inland Empire Comfort to evaluate whether it's time for a replacement before costs spiral further. Inefficient Cooling Performance Rising utility bills often indicate deeper issues with your air conditioning system, especially if you're experiencing inefficient cooling performance. If your AC struggles to maintain a comfortable temperature, it may be working overtime, resulting in higher energy costs. You might adjust the thermostat frequently, yet your home still feels warm and humid. This inefficiency could suggest that your system is aging or that underlying problems need attention. Ignoring these signs can lead to costly repairs in the future. Instead of spending more on an AC that can't keep up, it's wise to seek help from a professional. Experts in the field can provide tailored solutions to restore your comfort and efficiency. Frequent Repairs Needed Homeowners often find themselves making frequent repairs to their air conditioning systems, which can be frustrating and costly. If you're constantly calling for service, it might be time to evaluate a replacement. While repairs can temporarily fix issues, they often indicate deeper problems that won't go away. Here are some signs that frequent repairs may be a red flag: You're spending more on repairs than you'd on a new system. The same issues keep recurring, despite multiple fixes. Your AC unit is over ten years old, which increases the likelihood of breakdowns. Instead of pouring money into a failing system, investing in a new, energy-efficient model could save you money in the long run. Regular maintenance services can also prolong the lifespan of your new system. Consider reaching out to Inland Empire Comfort to assess your situation and explore your options. Uneven Cooling Throughout Your Home If you notice that certain rooms in your home feel stuffy while others are too cold, it could be a sign that your AC system is struggling to maintain consistent temperatures. This uneven cooling often indicates problems with your HVAC setup, such as inadequate airflow or duct issues. It might also mean that your AC isn't powerful enough for your home's size or layout. To address this, start by checking your vents and filters. Clogged filters can restrict airflow, causing temperature discrepancies. If everything seems clean and unobstructed, it may be beneficial to seek a professional assessment. A technician from Inland Empire Comfort can identify if your ductwork is improperly sized or if leaks are causing the issue. Additionally, they can perform heat gain calculations to determine the right air conditioning unit for your home's specific needs. Ignoring uneven cooling can lead to higher energy bills and discomfort. If the problem persists, you might want to consider replacing your AC unit for improved efficiency and comfort throughout your home. Strange Noises Coming From the Unit While uneven cooling can indicate underlying issues with your AC system, strange noises coming from the unit are another red flag that shouldn't be ignored. If you start hearing unusual sounds, it could signify serious problems that need immediate attention. Ignoring these noises might lead to further damage, resulting in costly repairs or replacements. Pay attention if you notice: Banging or clanking : This may suggest loose or broken parts inside the unit. Hissing sounds : This can indicate a refrigerant leak, which requires urgent professional intervention. Squealing or screeching : This often points to worn-out belts or motor issues. If you hear any of these sounds, it's time to consult a professional. The experts can help diagnose the issue, ensuring your home stays cool and comfortable. Don't wait until it's too late! Foul Odors Emitting From the AC If you notice foul odors coming from your AC, taking them seriously is crucial. These unpleasant smells can signal underlying issues, such as mold growth or electrical problems, which may pose health risks. Ignoring these odors could lead to more significant problems down the line. Let's explore what these odors might mean for your home and health, and how Inland Empire Comfort can help you address them effectively. Common Odor Causes Foul odors emitting from your AC can signal a variety of underlying issues that need immediate attention. These smells are often more than just unpleasant; they can indicate serious problems that could affect your comfort and safety. Always pay attention to what your system is telling you. Musty Smell : This could mean there's mold or mildew growing within your system, which needs to be addressed quickly by a qualified technician. Burning Odor : If you smell something burning, it might indicate electrical issues or overheating components that require urgent professional evaluation. Rotten Egg Smell : A sulfurous odor often signals a gas leak, which is dangerous and should be addressed immediately. If you detect any of these odors, don't hesitate to call for help from a trusted professional like Inland Empire Comfort. Health Risks Involved Ignoring foul odors from your AC can pose significant health risks. Musty smells often indicate mold growth in your system, which can trigger allergies and respiratory issues. If you're noticing a strong, chemical-like odor, it could signal refrigerant leaks that may lead to headaches or dizziness. Furthermore, burnt smells may suggest overheating components, posing fire hazards. Prolonged exposure to these contaminants can affect your overall health, especially for sensitive individuals like children or the elderly. If you detect any unpleasant odors, it's essential to act quickly. Don't wait for symptoms to worsen; consider reaching out to professionals for assistance. Prioritize your safety and comfort by ensuring your air quality remains clean and healthy. Excessive Humidity Inside Your Home Excessive humidity in your home can feel uncomfortable and stifling, making it hard to enjoy your living space. Not only does it create an unpleasant atmosphere, but it can also lead to various issues that signal it's time to contemplate replacing your AC. If you notice persistent humidity, it might indicate your system isn't adequately cooling your home anymore. Here are a few signs to watch out for: Mold or mildew growth : This can pose health risks and indicate excessive moisture. Condensation on windows : If your windows are consistently foggy, your AC may not be removing sufficient humidity. Increased energy bills : A struggling AC will work harder, leading to higher energy costs. If you're experiencing these issues, it's time to evaluate your air conditioning system. Inland Empire Comfort can provide reliable solutions to restore comfort and safety to your home.

Why Is Your Furnace Blowing Cold Air in Jurupa Valley, CA?