With cooler weather ahead, it’s time to start thinking about your furnace – and that includes how it smells. As a homeowner, you’re probably familiar with the slight burning smell you experience when turning on your furnace for the first time in the past six-plus months. This smell is caused when your furnace burns off dust that has collected on the heating elements while not in use. It should only last an hour or two at most, and is completely normal. While certain odors like this are temporary and harmless, others can be persistent, irritating and even dangerous.

Pay close attention if you recognize any of the following smells, and contact Wyckoff Heating & Cooling immediately if you do:


A sudden, unexplained smoke smell is likely the symptom of a mechanical or electrical problem in your HVAC system. Moving parts have the potential to overheat, lock up or even catch fire if the unit has not received routine maintenance. Common causes of persistent burning odors are dirty air filters blocking the heating system and perhaps causing overheating or blower malfunction. You may wish to change the filter and see if the burning smell goes away. If you see smoke coming from any part of your system, shut your thermostat off immediately and call Wyckoff Heating & Cooling.


If you smell mold or mildew circulating from your air vents, this may be a sign that you need to change your HVAC system filters. If you have changed the filter, and the smell persists, contact a professional for an inspection. This likely means the mold smell is more serious and could be the result of mold and mildew formation on coils and in ductwork, blocked drainage tubes, insufficient insulation or leaky ductwork. Left untreated, mold and mildew will spread and circulate to other parts of your home, not only leaving an unpleasant smell, but also becoming a health hazard.

Electrical, Metallic or Rubber

Each of these smells could be a potential fire hazard, indicating a malfunction of your HVAC equipment. First, inspect your registers to ensure nothing has fallen into them. If you do not see anything, the smell of electrical, metallic or rubber burning could mean the interior furnace components are getting too hot, or worn parts of your furnace are beginning to break down. Contact Wyckoff Heating & Cooling to diagnose the root cause of the issue and ensure your furnace can function properly and safely.

Natural Gas or Rotten Eggs

Though natural gas does not emit an odor on its own, sulfuric odor (or that rotten egg smell) is added so you can identify a leak. If you smell the warning sign of a natural gas leak, turn off the furnace, open windows and evacuate your home, taking family members and pets with you. Do not touch electrical equipment on your way out, as any spark could ignite the gas. Call your gas company or 911 immediately once outside your home. Once the leak is fixed, your HVAC service technician can get to work on your furnace.

Remember, when in doubt, contact us at Wyckoff Heating & Cooling. Your family’s safety is our number one priority, and we will take the time to ensure your furnace is safe and effective for the long winter ahead.