5 Reasons for Those Weird Furnace Odors


The sign of a good furnace or heating system is when you don’t realize it’s there. Sure, you feel warmth circulating through your home, but that should be the only effect you truly recognize. When you hear loud clanging or start smelling strange odors, those are signs that you need to get your HVAC system checked out. No one should have to deal with constant unpleasant odors spreading throughout their home. Instead, get to the bottom of the issue, and figure out how you can resolve it.

There are a number of ways things can go wrong with your furnace. Leaks, clogged filters, mildew, or excess burning can result in serious problems with your HVAC. The smell is a great indicator that something is going on. To avoid dangerous problems, turn off your furnace immediately, and call a technician to come to take a look. Let’s go over a few of the smells you may experience in your home and why you may be smelling those particular odors. Then, you can understand if it’s a dangerous problem, and look into the best way to move forward.

1. Natural gas is leaking throughout your home.

One of the most dangerous situations is a gas leak. This can spread toxins like carbon monoxide and other gases throughout your home. This may cause illness, disorientation, or fatigue. The trouble with this issue is that natural gas is completely odorless. However, many gas companies have added a safety precaution and infused these gases with a substance called mercaptan. When leaked, this will smell a lot like rotten eggs, which is one of the furnace odors you shouldn’t ignore. When you smell this odor, it’s a sign you should turn off your furnace immediately and call for help to avoid breathing in anything dangerous.

2. Wires are burning or melting in the unit.

Another scent you may experience is a metallic or chlorine-like smell. This is usually caused by wires or other pieces burning or melting within your furnace. The burning smell occurs more often with older furnaces that have experienced a great deal of general wear and tear. Regular maintenance can help avoid this problem and keep your unit functioning for longer.

3. Spilled oil or other objects are burning by the furnace.

Your furnace gets extremely hot, which is the whole purpose of the system. However, if other objects or excess oil get too close, they may melt and emit a burning oil smell. If you overflowed your oil tank or left a toy too close to the burner, this may happen. Usually, this is a less dangerous issue as long as it goes away after a few days. If it lingers, you may want to call an expert.

4. Mold or bacteria are growing in the air ducts.

Your furnace pumps warm air throughout your home by using vents and ducts. During season changes, a constant back and forth between heating and air conditioning can cause moisture to build up in these air ducts. Any general bad smell like a locker room, dirty socks, spoiled food, etc. can be a sign there are bacteria growing on your unit’s heating coils. This should be easily remedied with a thorough cleaning.

5. Your air filter needs to be cleaned or changed.

Another part of your HVAC system that can cause problems and strange smells is your air filter. This catches dust and debris, but when dirty, it can let more of those things escape. If you’re noticing a musty smell or seeing more dust around your home, a dirty air filter could be one of the possible reasons. Again, this is usually an easy fix that involves cleaning or replacing the air filter.