Why Is My Furnace Blowing Cold Air? A Littleton & Denver Homeowner’s Troubleshooting Guide

You’re snuggled up and binge-watching your favorite show when your furnace suddenly kicks on. Instead of a gust of hot air, the vents feel cold. Outdoors, a Denver cold snap is brewing. 

When your family is facing a furnace failure in the middle of freezing weather, the situation can quickly inspire panic. For local homeowners, this is an incredibly common, stressful situation. 

While some problems can be fixed on your own in just a few minutes, many heating, ventilation, and air conditioning (HVAC) issues must be repaired by a trained technician. 

To help you stay warm, we’ll walk you through some of the common reasons why your furnace is blowing cold air in Littleton and Denver. We will cover the key signs that you may need to reach out to the HVAC technicians at Elkhorn Heating, Air Conditioning, Plumbing & Electrical for help.

Quick Homeowner Checks Before You Call

If your furnace is not heating the house, there are a few proactive steps you can take as part of your heater blowing cold air troubleshooting. The following steps do not require professional help, so you can do them on your own. 

Check the Thermostat Settings

First, you should check to make sure that your thermostat settings are correct. Sometimes, furnaces will be set to “Cool” or “Fan Only” mode instead of “Heat” mode. You should also check the temperature to make sure none of your family members changed the setting.

Then, check the fan setting. It should be turned to “Auto” instead of “On.” If the fan is set to “On,” it will run the blower continuously. Because your furnace is only running part of the time, this can make the air feel cold. 

Check and Replace the Air Filter 

Air filters play an integral role in your home’s HVAC system. They filter out airborne particles, preventing your unit from becoming dirty. However, for the filter to do its job, it must be clean. 

Once a filter becomes clogged, it can restrict airflow. This forces your furnace to work harder to heat your home and can lead to overheating. If the furnace overheats, it triggers the furnace to automatically shut down as a safety feature. Unfortunately, this issue is particularly common in our area because Colorado’s dry, dusty winters lead to significant filter buildup.

To avoid this problem, change the filter every 30 to 90 days. During periods of peak use, it should be replaced more frequently.

Make Sure Vents Are Open and Unblocked

Sometimes, furniture or rugs can end up covering up a vent. Registers can also get closed by accident. To make sure the lack of hot air isn’t because of blocked vents and closed registers, periodically inspect these areas for obstructions.

Check the Pilot Light or Ignition

Many older furnaces come with a standing pilot light. You should check to make sure the pilot light is still on. If the light is shut off, it is likely the reason why you’re dealing with a furnace blowing cold air in Denver.

Newer furnaces use an ignition system, so a failed igniter can prevent the burner from lighting. However, this isn’t an issue you can repair on your own.

Reset the Furnace

Before you reach out for professional furnace repairs in Littleton and Denver, there’s one last troubleshooting step you can attempt on your own. A power-cycle involves turning the furnace off and on, which completely resets its control board. It is also a fast way to clear any error codes and glitches that shouldn’t be occurring in the system. 

To power-cycle your furnace, start by turning it off at your thermostat. Then, wait 30 seconds to make sure that the entire shutdown process is complete. Once you turn it back on, temporary glitches should be resolved. If the furnace still doesn’t work properly, you should schedule a professional furnace inspection.

Common Mechanical Causes That Require a Pro

So, why is my furnace blowing cold air? If basic troubleshooting isn’t effective, it’s time to schedule a furnace repair appointment to get your problem inspected and diagnosed. Elkhorn offers 24/7 emergency services, so you can get immediate support.

Dirty or Faulty Flame Sensor

Furnace flame sensor issues are some of the most common reasons why furnaces blow cold air. Normally, the flame sensor is responsible for detecting that a flame is present. This is a safety mechanism that prevents gas from leaking into your home if the furnace doesn’t ignite.

Over time, the flame sensor can become coated in carbon buildup. Because the sensor cannot detect the flame, it briefly shuts down. During this interim, the furnace will only push cold air. By scheduling repairs, you can quickly get your flame sensor cleaned so that the furnace can function normally again.

Malfunctioning Ignition System

Ignition systems are another common cause for cold air. If you have a faulty electronic ignition module or a cracked hot surface igniter, the burner won’t light at all. Your blower will continue pushing air into your home, but the air will be cold.

Cracked Heat Exchanger

Your heat exchanger is responsible for transferring combustion heat into your home’s air. If the heat exchanger becomes cracked, you’ll notice cold air coming from your vents. 

Cold air is not the only problem to watch out for. If the heat exchanger is cracked, it can cause carbon monoxide to leak into your home. This represents a major safety issue for your family because of the risks associated with carbon monoxide poisoning. You should immediately call for professional repairs.

Failing Blower Motor or Control Board

If the furnace’s control board is sending incorrect signals or the blower motor is malfunctioning, it can result in cold or inconsistent airflow. Both of these problems should be addressed by a professional.

Condensate Line Blockage 

High-efficiency furnaces produce moisture that must be directed out of your home through the condensate line. If the condensate drain becomes clogged, the furnace has a safety switch that automatically shuts the furnace down. We often see this problem in Littleton and Denver with 90% AFUE or higher units.

Why This Problem Is Especially Common in Colorado Winters

Our area is known for its natural beauty, outdoor adventures, and unique climate. As a part of this beautiful environment, there are also some challenges. When you live in this area, your HVAC system has to put up with extreme temperature swings, extra dust, and other issues. The following are a few reasons why you’re more likely to experience a furnace blowing cold air in Littleton and Denver.

Extreme Temperature Swings

One of the most important causes of furnaces blowing cold air is our drastic temperature swings. Denver and Littleton can experience a temperature swing of over 50°F in just 24 hours. This causes the furnace to cycle on and off more aggressively. The frequent cycles result in more wear on flame sensors, blower motors, and ignition components.

Dry Air and Dust

Colorado has an arid climate, which means we have more airborne dust. When this dust is present, it can quickly clog filters and coat flame sensors. The best way to remedy these issues is by changing your air filter more often and getting your flame sensors cleaned by a professional.

Altitude Affects Combustion

Another factor is our high altitude. Because we are around 5,280 feet above sea level, there is less oxygen in the air. The lower oxygen levels directly impact the burner performance on your furnace. 

This is why it’s so important to have your furnace set up by a local HVAC technician. As a local company, we understand our climate’s unique needs. When we install furnaces, we ensure that they have the exact high-altitude calibration that our area calls for.

Older Housing Stock

Many of our Littleton neighborhoods were built between the 1970s and 1990s. Today, many of them still use their original furnace. Aging furnaces are more prone to component failures, making furnace repairs more common.

When To Call Elkhorn Heating & Air Immediately

If you’re dealing with a furnace blowing cold air in Denver, don’t delay getting help. While some issues can be troubleshot on your own, others indicate a major repair or potential danger. As soon as you notice any of the following problems, immediately call for HVAC emergency repairs in Denver.

You Smell Gas 

The smell of gas is an immediate concern. Immediately shut off your furnace and evacuate. As you leave your home, you can open up windows and doors to help ventilate the house. Once you, your family, and pets are safely outside, you should call your utility provider to shut off the gas line. Then, call our team for emergency repairs.

Your Carbon Monoxide Detector Goes Off

If your detector is going off, it is an immediate cause for concern. A cracked heat exchanger can leak carbon monoxide into the air. Because this gas is odorless, invisible, and tasteless, you won’t be able to tell when levels are dangerously high. If your detector alerts you to the presence of carbon monoxide, immediately evacuate your home and call 911. Afterward, schedule an inspection and HVAC repairs in Denver.

The Furnace Repeatedly Shuts Off After a Few Seconds of Running

When your furnace starts short cycling, it is often a sign that there is a problem with your flame sensor, ignition, or safety switch. Because of the safety risks involved, you should immediately call to schedule a professional inspection.

You’ve Checked the Basics and the Problem Persists

When you have a furnace blowing cold air in Denver, you can’t simply put up with the issue forever. Our winters are too cold to go without heat for any length of time. If you have already checked your filter and thermostat, it is time to reach out to a professional to get the problem solved.

How Elkhorn Diagnoses and Fixes the Problem

At Elkhorn, we have years of experience working with local HVAC systems. We understand the drastic temperature swings, high altitude, and arid climate of Colorado. As a result, we’re able to offer some of the area’s leading furnace maintenance and repair services. If you have a furnace blowing cold air in Denver, our HVAC technicians will quickly use the following steps to resolve the problem. 

• Thorough System Inspection: You and your family deserve a high level of peace of mind. Our technicians don’t just guess about the problem. We methodically check each component for signs of a problem. During each inspection, we’ll review your thermostat wiring, flame sensor, blower operation, heat exchanger, airflow, and ignition for signs of damage.
• High-Altitude Expertise: Our Littleton-based company has been serving the Denver metro area since 1998. We’re proud to be a local team of technicians. Thanks to our experience in the area, we understand the unique demands of Colorado’s high altitude on furnaces and HVAC equipment.
• Transparent Pricing and Honest Recommendations: At Elkhorn, we believe in creating customers for life. As a part of that mission, we are committed to providing honest recommendations and transparent pricing on each project. We’ll immediately tell you if a $150 flame sensor cleaning will solve the problem or if your 20-year-old furnace is finally in need of a replacement. Our technicians will walk you through each course of action, so you understand the long-term value of each decision.
• 24/7 Emergency Service: When a disaster strikes, you can’t afford to wait it out. If your furnace starts blowing cold air during our next Colorado cold snap, our HVAC technicians are just a phone call away. Elkhorn offers around-the-clock emergency HVAC repairs because we know unexpected breakdowns don’t wait for business hours.

Keep Your Family Comfortable Year-Round 

When you’re dealing with a furnace blowing cold air in Denver, you can’t afford to wait for your next HVAC appointment. While a furnace blowing cold air doesn’t mean an HVAC failure is imminent, it does need to be looked at. If you delay repairs, a minor fix can quickly spiral into a costly repair or major safety hazard. By reaching out to Elkhorn Heating, Air Conditioning, Plumbing & Electrical, you can get a professional inspection and repairs.

Need emergency heating repair? Elkhorn Heating, Air Conditioning, Plumbing & Electrical offers 24/7 service for Denver and Littleton homeowners. Call us now or schedule online!