Common Furnace Smells: Causes and Solutions
By:
The AC Guy
| Published 02/29/2024
If you’ve ever noticed strange smells coming from your furnace, don't panic! Most of the time it's nothing serious, but it is something to check out. As your furnace works hard to keep you warm all winter long, it's normal for a few odd odors to develop. But some smells can indicate an issue that needs attention. Here are the most common furnace smells, what's causing them, and when you need to call in the pros.
Burning Odors: Dust Buildup or Electrical Issues
If your furnace kicks on after being idle all summer and you notice a burning smell, it’s probably just burning off dust that accumulated over the off-season. This burning dust odor should clear up within a few hours as the dust burns away. However, if the smell persists or is very strong, it could indicate an excessive buildup of debris that needs to be professionally cleaned to prevent potential fire risks.
On the other hand, if your furnace smells like burning plastic or electrical wires, that signals an issue that requires immediate attention. This could indicate overheating components like the blower motor, damaged wiring, or even a cracked heat exchanger. Any of these situations can be dangerous, so shut off your furnace right away and schedule an emergency service call.
The AC Guy’s licensed technicians have years of experience diagnosing and repairing furnace issues. We’ll inspect your system to determine the cause of the burning smell, perform necessary cleaning or repairs, and get your furnace functioning safely again. Don’t put off dealing with potentially hazardous electrical or overheating issues—your home, health, and safety should be top priorities.
Rotten Eggs and Sewer Smells: Gas Leaks and Sewer Problems
Rotten Egg Smell: Gas Leaks
If there’s a rotten egg smell coming from your furnace, that’s a bad sign. Gas companies add a distinctive smell to the otherwise odorless natural gas to help detect leaks, and it means you’ve got a serious issue that requires immediate attention.
Shut off your furnace and call a qualified HVAC technician right away. They’ll send someone out to inspect your furnace and gas lines to locate the source of the leak. Don’t run any risks here, as gas leaks are extremely dangerous and can cause explosions, fires, or exposure to toxic fumes. That means keeping away any open flames or electrical switches.
Sewer Smell: Dried-Out Sewer Trap
On the other hand, if the smell isn’t constant and you’ve recently had dry weather, the culprit could be a dried-out sewer trap. Sewer traps, also known as P-traps, are U-shaped pipes under drains that hold water to form a seal and prevent sewer gasses from entering your home. When water evaporates from the traps, the gasses can escape, giving off that rotten egg odor.
To fix a dried P-trap, pour a gallon of water down any floor drains in your basement, like sinks or laundry drains. The water will refill the trap and re-create the seal to stop the smell. If the smell persists after a day or two, you may have a cracked sewer or drain line allowing gasses to seep in, which requires professional plumbing repairs.
Either a gas leak or sewer issue requires prompt attention to avoid risks to your safety, health, and home. Don’t delay contacting the necessary utility companies and technicians to investigate and resolve the problem. You’ll want to take action right away to eliminate the odor and ensure proper, efficient, and safe operation.
Musty, Moldy Smells: Moisture and Humidity Issues
Musty Smells: Clogged Drain Lines or Malfunctioning Humidifier
Have you noticed a musty or moldy smell coming from your furnace lately? This could indicate excess moisture buildup within your HVAC system, which allows mold and mildew to thrive. The AC Guy technicians frequently find the source of musty furnace smells to be clogged drain lines or a malfunctioning humidifier.
Check your furnace’s drain lines first. Over time, condensation and debris can clog up the lines that remove water from your furnace, causing it to overflow into the system. Clean out the drain lines to remove any blockages. If the smell continues after clearing the lines, it’s best to have The AC Guy inspect your furnace. Our techs can test your humidifier to ensure it’s functioning properly and not over-humidifying your home.
Moldy Smells: Excessive Humidity
Excessive humidity is another common cause of musty furnace smells. High humidity creates the perfect environment for mold growth in your HVAC system and air ducts. Use a hygrometer to monitor the humidity levels in your home, especially in the summer, and aim for keeping humidity below 60% to prevent musty smells and other issues. You may need to run a dehumidifier to remove excess moisture from the air.
Frequently change or clean your furnace filters as well. Clogged filters reduce airflow and efficiency, allowing more moisture to build up in your system. For the best results, replace flat filters monthly and pleated filters every 3 months.
If the musty smell in your furnace persists, don’t hesitate to schedule a service call with The AC Guy. We have the tools and experience to fully inspect your HVAC system, locate the source of the odor, and perform necessary repairs or duct cleaning to eliminate the smell and improve your indoor air quality. Your comfort and safety are our top priorities.
Call The AC Guy to Fix Heater Issues
Now that you know of the causes and solutions of heater smells, you don’t need to panic if you notice an odd smell coming from the vents. Simply check the filter, clear the drain line, and have a service tech check for gas leaks or wiring issues. The furnace is the heart of your home’s comfort, so keeping it in good shape with regular maintenance will ensure many more years of warmth in the winters to come.
Whether it’s a simple fix like duct cleaning or a more complex repair, you can count on The AC Guy to resolve any furnace smells or issues promptly and professionally. We service all makes and models of furnaces to keep homes in The Woodlands, Texas community warm and cozy all winter long. Give us a call today to schedule your appointment!
