What Is That Smell Coming From My Furnace?


If you have been using the same furnace for years, it is possible you are detecting odd smells coming from your system. However, some furnace smells are fairly normal, while others indicate you could have a serious problem on your hands.

If you have ever asked yourself, “why is that smell coming from my furnace,” keep reading for the answers you need, and remember that for all your furnace repair and replacement needs, you can always count on our experts at Service Legends.

Top 5 Furnace Smells

1. Sulfur/Rotten Eggs

That sulfuric, rotten egg-like smell coming from your furnace is definitely something you want to be concerned about, because it may be the result of a gas leak. While natural gas is definitely a great fuel source for a furnace, due to its high combustibility and general energy efficiency, it can also be extremely dangerous if a leak occurs.

Watch out for other signs this is happening, like symptoms such as nausea, headaches, confusion, and dizziness. If you detect a natural gas leak coming from your furnace, make sure you avoid anything in your home that could be flammable and get your family out of the house ASAP.

Related Content: Safety Tips to Prevent Furnace Fires

2. Gym/Dirty Sock Smell

The odor that you smell when you step into a locker room, that smell of sweat and dirty socks, is the result of moisture and bacteria accumulation. You may notice the same smell in your furnace when excessive condensation occurs, usually because the thermostat has been frequently turned up and down, causing condensation to form on the coils.

Call a technician for thorough cleaning if you pick up this stench coming from your system.

3. Diesel Fuel

Although furnaces don’t run on the same type of diesel you would put in your car, the fuel sources may smell similar if you use an oil-based system. When there is too much oil in your furnace, fog can form. This fog will burn when it interacts with your heating element, leading to that diesel odor you are smelling.

Be careful of putting too much oil in your furnace, as this can turn it into a fire risk, and always call a technician if you smell burning in your furnace, since this may force you to repair or replace your entire system. And speaking of burning…

4. Electrical Burning

When your furnace’s fan blower starts to age, it may consume more electricity, causing sparking in your system. The smell this results in is similar to the odor you will notice when dealing with burnt wiring.

A sparking fan blower can cause damage to your system’s wiring and insulation, in addition to posing a fire risk to your whole home, so do not hesitate to give us a call if you smell burning coming from your unit.

5. Dust/Must

If your furnace has been shut off for months, just accumulating dust, you may notice a musty odor appear in your house when you then turn your furnace back on. This smell is all the dust and debris in the system being burnt up. While there technically isn’t anything dangerous about this issue, it is a good idea to change your system’s air filter if you detect this smell, as it will help improve your furnace’s efficiency and strengthen your indoor air quality.

Old air filters strain your HVAC system and are often what causes other malfunctions. You can add at least five years to your heating and cooling system’s life by replacing your air filter at least every other month.

You can also avoid having to deal with this odor every winter season by calling an HVAC professional for some annual maintenance. At Service Legends, we offer three options for furnace maintenance that will fit every budget, every time.

Schedule Your Furnace Maintenance

It’s a good idea to get your furnace checked by a professional every year, before winter sets in. This way you can be sure it’s in good working order and won’t leave you and your family cold.

515-657-6634Request Appointment Online

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