Furnace and Carbon Monoxide: What Every Colorado Homeowner Needs to Know

As the temperature drops across Colorado, furnaces become the unsung heroes keeping our homes, small businesses, and commercial spaces warm and comfortable. But with this essential heating comes a responsibility every property owner should take seriously: understanding the risks of carbon monoxide (CO) exposure from your furnace. This silent, invisible gas can pose a serious health hazard without warning. At Alloy Heating and Cooling, our mission is to keep your family, employees, and customers safe by sharing the facts about furnaces and carbon monoxide.

Understanding Carbon Monoxide in Furnaces

What is Carbon Monoxide?

Carbon monoxide is a colorless, odorless, and tasteless gas produced whenever fuels like natural gas, propane, oil, or wood are burned. It is dangerous because it can build up indoors and is extremely difficult to detect without specialized equipment.

How Furnaces Produce Carbon Monoxide

Most Colorado homes are heated by gas or oil furnaces. When these furnaces burn fuel, they create heat as well as byproducts like carbon monoxide. A properly functioning furnace safely vents these gases outside. However, if something goes wrong, CO can leak into your living spaces.

Why Colorado Homeowners Should Be Concerned

Colorado’s cold winters mean furnaces run for months on end. According to the Colorado Department of Public Health, hundreds of Coloradans are treated for CO exposure each year, often due to faulty heating appliances. The risk is higher in well-insulated, tightly sealed homes common in our area, where fresh air exchange is limited.

Common Causes of Carbon Monoxide Leaks in Furnaces

Cracked Heat Exchangers

The heat exchanger is the metal component that separates combustion gases from the air that circulates through your home. Over time, metal fatigue or corrosion can cause cracks. When this happens, CO can seep into your home’s air supply. For example, a Greenwood Village homeowner called us after noticing a yellow burner flame. Inspection revealed a cracked heat exchanger, which we replaced to restore safety.

Poor Ventilation and Blockages

Flue pipes or vents remove combustion gases. If these are blocked by animal nests, snow, ice, or debris, CO can back up into the home. In Highlands Ranch, a small business owner experienced repeated headaches among staff and found a bird’s nest blocking the furnace vent. Clearing the blockage eliminated the CO hazard.

Improper Furnace Installation

Incorrectly installed furnaces may have venting issues that prevent CO from exiting the building. DIY or unlicensed installations are especially risky. At Alloy Heating and Cooling, we have seen cases in Aurora and Littleton where improperly sloped vent pipes caused CO buildup. Professional installation follows strict codes to prevent these issues.

Lack of Maintenance

Neglected furnaces are a common source of CO leaks. Dirty burners, worn parts, or failing safety controls can all lead to problems. Annual professional maintenance helps catch these concerns before they become dangerous.

Warning Signs of Carbon Monoxide from Your Furnace

Physical Symptoms in People and Pets

Because CO is hard to detect, physical symptoms are often the first sign of trouble. Homeowners in Centennial reported persistent headaches, nausea, and confusion that disappeared when they left the house. Pets may become lethargic or exhibit unusual behavior. If everyone feels better outside, suspect CO exposure.

Visual and Odor Clues Around Your Furnace

While CO itself has no odor or color, other warning signs include:

• Soot or scorch marks on or around the furnace
• Stale or stuffy air in the furnace room
• Excess moisture on windows or walls near the furnace
• Yellow or flickering furnace flames (they should be steady blue)

Unusual Furnace Operation

If your furnace is cycling on and off more frequently, struggling to heat, or making strange noises, these could indicate a problem. In Parker, a homeowner noticed the furnace shutting off unexpectedly. Our technicians found a blocked vent, which was quickly cleared to restore safe operation.

How to Prevent Carbon Monoxide Exposure in Your Home

Annual Furnace Inspections

Regular professional inspections are the best way to prevent CO leaks. At Alloy Heating and Cooling, we check heat exchangers, burners, controls, and venting during every maintenance visit. We also use specialized CO detectors to identify hidden leaks. Annual inspections are especially important before winter starts in Colorado.

Installing and Maintaining CO Detectors

Place carbon monoxide detectors near bedrooms, living areas, and on each floor of your home, as well as near your furnace. Test detectors monthly and replace batteries twice a year. In commercial settings, detectors should be installed according to code and checked regularly.

Proper Furnace Use and Care

Follow your furnace’s operating instructions and never attempt repairs or modifications yourself. Keep the area around your furnace clear and do not block vents. Avoid using ovens, grills, or portable heaters indoors, as these can also create CO hazards.

What to Do If You Suspect Carbon Monoxide in Your Furnace

Immediate Steps to Take

If your CO detector sounds or you suspect a CO leak:

• Leave the building immediately. Bring everyone, including pets, outside.
• Do not try to find the source or ventilate the building yourself.
• Call 911 or your local emergency number from outside.

Do not return until emergency personnel say it is safe.

When to Call Emergency Services

Anytime a CO detector sounds, or if anyone is experiencing symptoms of CO poisoning, treat it as an emergency. In Brighton, a family was saved when their detector sounded late at night. Emergency crews found a leaking furnace, and the family was treated for mild symptoms.

How Professionals Address CO Leaks

Certified HVAC technicians, like those at Alloy Heating and Cooling, will perform a thorough inspection to locate the source of the leak. This may involve testing the heat exchanger, checking venting, and using CO meters. Repairs could include replacing damaged parts, clearing blockages, or installing a new furnace. We ensure the problem is fully resolved before restoring service.

Conclusion

Carbon monoxide is a real threat, but with proper knowledge, maintenance, and professional support, you can keep your family, employees, and customers safe. At Alloy Heating and Cooling, we proudly serve Greenwood Village, Englewood, Littleton, Lone Tree, Highlands Ranch, Parker, and the surrounding Colorado communities with expert furnace care and CO safety solutions. If you have concerns or want to schedule an inspection, contact our team today.

Frequently Asked Questions