Is your furnace giving off a funky smell when you turned it on again? Chances are you’ve got a few bad things going on that need immediate attention. Funny smells are never a good thing, especially when they come from systems that use or create heat. Surveys show that a majority of American households use one of three types of heating equipment. These are the natural gas furnace, electric furnace, and heat pump. Those who own natural gas and electric furnaces notice these weird smells more often. If you want to know what each furnace smell means and how to fix them, read on below. 1. Strong Chemical SmellYour heating unit uses chemicals in its heat exchanger to function. The heat exchanger takes the heat from the combustion chamber and cycles it into the plenum. If it’s broken, the chemicals created by this cycle leak out of its course and into your home. The strong, sharp smell of chemicals from your furnace is always dangerous. This smell might remind you of formaldehyde if you’re familiar with the compound. Fatal carbon monoxide fumes may also leak out from a broken heat exchanger component. Get immediate help from a professional when you get a chemical smell from your furnace. 2. Electrical Burning or Smell of OzoneHave you ever been in a thunderstorm? If you have, you might be familiar with the smell of ozone. If you haven’t a clue about what ozone smells like, it’s sharp and pungent, like chlorine. When your furnace is giving off this smell, it means that it’s overheating. It will use up more electricity to drive through the resistance. This increased use of voltage causes too much heat buildup in the motor. This heat can cause other problems like melted wire insulations. When your wire insulations melt away, the furnace will begin shorting or sparking. The electrical shorts and sparks produced by your furnace cause the smell. When you notice the ozone smell, it’s important to cut the power to your unit as soon as possible. Otherwise, these sparks and melted wires may start a fire. Remember to get a certified technician to check the furnace before you turn it on again. 3. Sulfur or Rotten Egg OdorIt’s a serious problem if you’re getting a whiff of rotten eggs from the furnace. The source of the smell is likely to be natural gas. It makes a great fuel source for heating because it’s very flammable. However, natural gas is harmful to your health. Headache, dizziness, and nausea are only some of its symptoms. You might also see problems in sick pets or dying plants. In their natural states, propane and natural gas are odorless. Gas companies add mercaptan as a safety precaution in cases of gas leaks. Mercaptan is a harmless chemical that gives off a sulfuric smell to make gas leaks easier to detect. The moment you smell rotten egg coming from your furnace, act fast. Don’t wait for the gas to affect you and your family’s health. Shut off the gas furnace and call a professional to inspect the system. 4. The Smell of Burning Oil or DieselAny kind of burning smell isn’t a good sign, especially when it comes from the furnace. The particular smell of burning oil is an indicator of an overheating component. This smell may be like that of burning hot plastic, metal, or rubber. If you have an oil furnace, the furnace might not use up all the oil that passes through the burner. This creates a fog that can ignite. If you filled the oil tank, be careful of spillage, which causes the odor when it dissipates. Observe the smell. If it lingers for more than a couple of days, check your tank for an oil leak. Another possibility is the proximity of certain items to your basement furnace. Place stored items in the basement as far away from the furnace as possible. If they’re too close to the pilot light, they can melt or catch fire. 5. Moldy, Damp, or Dusty SmellThe ducts of your heating unit also need cleaning on occasion. Failure to clean them can lead to unwanted dust buildup or mold infestation. Since the furnace is part of what controls your air indoors, it’s ideal to keep it clean. A clean furnace gives you the best quality of indoor air. Untended furnaces can bring out damp or dusty basement smells. Old furnaces can even spit out dust and debris, which is a sign to replace your furnace. The warmth in your furnace can burn the dirt and dust in your air ducts. This burning can also cause a bit of a smoky smell in your home. However, a persistent smell shows that you need to clean up or buy a new air filter. Mold infestation is another harmful furnace problem. Mold infestation can cause flu-like symptoms, coughing, and sneezing. Call a professional to clear out the ducts and ensure that mold doesn’t grow back. 6. Locker Room SmellThe last smell you expect from your furnace is the odor of dirty socks, old cheese, and corn chips. Often, this smell occurs because of bacteria buildup in the coils of your heating system. You won’t know it but the spring and fall seasons are the best time for bacteria to build up. The outdoor temperature drops in the coils, causing them to cool. When you get home from school or work, you turn up the thermostat. These changing temperatures build up condensation in the coils. It’s the perfect environment for bacteria to grow in. The best way to fix this problem is to clean your furnace. Replace your air filter and clean up the evaporator coils. Use a non-acidic coil cleaner for the coils. At this point, there shouldn’t be a trace of the dirty sock smell. If you still get a whiff of the odor, HVAC professionals can do a deeper and more thorough clean of your furnace. Keep a Warm and Odor-Free HomeWhenever you notice an unusual furnace smell, be alert. Some of these smells are hazardous to the health while others only spell bad news for your heating unit. Now, you know which ones are harmful and need immediate solutions. That’s it for our guide on what funky furnace odors mean. If you enjoyed this guide, feel free to check out our other blog posts. If you want your furnace checked, contact us now.