Demystifying Odd Furnace Smells


When it comes to heating in Austin, it is worth knowing as much as possible about what behavior is regular and normal, and what constitutes a sign that something is off and deserves attention. Furnaces are hardy, built-to-last machines that will diligently provide you with the much-needed warmth you require in the fall and winter in order to stay comfortable and satisfied in your own home. But, that being said, they can’t do this perfectly indefinitely without a little attention being thrown their way every once and a while, whether that’s in the form of some easy maintenance or major repairs.

We’ve already looked at some noises that you might hear your furnace emitting at some point and those could mean and today we’re going to look at another type of sign, smells. At some point in your life, you may have noticed certain characteristic smells in your house that seem to correlate with the heater being on but you may not have had any way to decipher what that smell meant or what to do about it. That’s the purpose of this type, to demystify those different sorts of smells and give some answers as to what they mean and what actions they beg.

Four Specific Smells

Unlike strange noises, which can take on all different forms when we’re talking about home central heating systems, smells that might at some point come from your furnace generally can be put into one of four categories. In a way, this makes learning what a smell from your furnace could mean easier than when it comes to sounds and noises because it could be harder to remember how to differentiate between a rattling noise and a grinding noise and a popping noise. Smells are much more distinct. Generally, you’ll be able to put a scent you smell that comes from the central heating system into one of these four boxes.

This kind of smell can be described as like, as the name implies, rotten eggs, or gas, or oil, or sulfur. Any way you describe it, it is likely going to be plenty unpleasant and will immediately grab your attention. What could be the cause of this smell? Well, it could be one of several things.

If you have a furnace that runs on oil and the smell itself is more oil-like then you could have an oil leak or just a clogged filter. Which one of the two problems it is will determine whether an oil smell is the sign of a major or minor problem. A clogged filter can cause this smell and is a minor problem. Change the filter and the smell should go away. If the smell continues, call an Austin heating professional to check for a possible oil leak. An oil leak can result in a major problem.

If your furnace is a gas furnace and the smell is more on the gas and rotten egg side then a gas leak is a likely culprit. One positive side of smelling this very particular smell is that you can identify the cause and therefore the right course of action fairly easily. The biggest downside is that this is potentially a very serious situation. This is the case because most gas companies scent their gas with a discernible smell to let technicians and residents know that they could have a leak since gas is unscented on its own.

The problem with the rotten egg smell in your home is that it could cause an explosion or fire in your house since you have gas in the air. If you’re near the furnace, go ahead and turn it off as soon as possible and open up windows to allow clean airflow. Next, you need to leave your home and call the gas company for service. They may need to turn your gas off before your furnace can be fixed since it’s dangerous to work in an area with a gas leak.

A musty odor in air is a fairly common problem when it comes to furnaces and is often one that people notice the most when they first turn their heaters on at the beginning of the cold season. A lot of dirt and dust and other contaminants can build up in the system especially if it has been sitting dormant for a while. One common cause of this musty odor that you smell when the furnace turns on is the smell of mold that has built up either in the ducts or in the furnace filter.

If the filter is at fault the solution is fairly simple and easy. The musty odor comes from dust and dirt collecting in the air ducts, which gets blown throughout your home when the furnace turns on. If this smell persists throughout the heating season, it could mean you need to change the air filter. A musty smell could also indicate that mold is trapped on the furnace filter or on the humidifier filter if you have one.

Mold throughout the system poses a bigger problem, however. This will require a more extensive cleaning that should probably be completed by an expert.

These last two smells both could be grouped under the category of burning smells but because they differ in both their scents and causes we’ll break them into two groups. This first one is referring to smells similar to hot metal, burning oil, hot plastic or rubber. Electrical smells and metallic smells are generally pretty distinct for the average homeowner since they don’t occur too frequently. In some cases, these smells will be a bit like burning wires, though they generally have a slightly different odor. In other words, if this is your problem you’ll likely be able to recognize it even if you can’t envision it right now.

Electrical smells coming from your furnace often indicate certain components on the inside are getting too hot. What this means can be further deciphered by what behavior accompanies the smell. If electrical smells come with a furnace that randomly shuts itself off, it’s likely a protective mechanism that won’t allow the furnace to run anymore and you’ll need to call for service immediately from a professional heating technician to use the furnace.

Another possible cause is old and outdated parts starting to burn. Mechanical smells in your furnace may also indicate that certain parts on the inside that are literally made of rubber or metal are actually burning due to old age and general wear and tear. These parts will need to be replaced, but this is generally a minor repair that won’t cost you too much money.

Regardless, these sorts of smells are no laughing matter and if you want the best chance of your furnace needing minimal repair you’ll want to take action immediately. If you notice electrical smells or metallic smells coming from your furnace, you need to shut it off immediately and not continue running it, even if it’s cold outside and in your home. Call your service provider for a repair as soon as you can, and once the furnace has been fixed, monitor it closely for a day or two to make sure the smell is gone.

The most common kind of smell you’ll probably experience if you do experience any when it comes to your furnace is a sort of dusty burning smell. This could very likely just be dust that has built up in the filter that will shortly burn away. Many people experience this especially when they turn their heaters on for the first time in the season. But, this isn’t the only thing that can cause a general burning smell, so you shouldn’t take it lightly.

Experts say that burning smell is generally completely normal and nothing to worry about, but there are some instances where it can mean trouble. A big indicator of whether this is just the routine burning of dust as the heater gets going for the first time or a more serious problem is how long the smell lasts. If you smell something like burning dust the first few times you turn your heater on in the fall or winter and it lasts about 45 minutes or so then you’re probably okay. If the problem persists, however, it could be something like burning insulation. Insulation could have come loose in the ductwork and started to burn. Fortunately, that insulation is fire retardant and firefighters say heating systems as a whole don't fire hazards.

Regardless, it’s worth changing your filter at the beginning of the heating season, especially if you smell burning dust, as a dirty filter could be the cause as well. Filters in forced-air furnaces are important to proper heating. Filters remove particulates like dust, pet dander, pollen, mold spores and more from the air before the unit gets warmed up. If your filter is filthy, the airflow becomes blocked and cannot flow freely through the filter. When this happens, there is a possibility that the unit will overheat.

If time doesn’t get rid of the dusty burning smell and replacing your air filter doesn’t either, you need to get the help of certified heating and cooling professional. It could be a serious problem with your unit like a busted heat exchanger or you could simply need a deep cleaning that you won’t be able to take care of on your own.

  1. Rotten Egg Smell:
  2. Musty Odor:
  3. Hot Metal/Electrical Smells:
  4. Dusty Burning Smell:

Furnace Smells and Heating Repair in Austin

Like strange noises, strange smells can definitely be concerning when it comes to our heaters, but there’s no need to panic. Hopefully, with this rundown on some of the most common smells, you might encounter with your furnace you’ll be able to safely and swiftly take care of the problem in the case of a dirty air filter or reach out to a professional in the case of something more serious.

AC Express can provide same day heater repair with our experienced technicians who can help you identify the cause of any problem with your heater and perform expert Austin heater repair. If you need heater repair in Austin, Texas, or any of the surrounding towns, from Cedar Park and Georgetown to Lakeway and Leander, contact us today!