furnace smells like gas

What to Do When Furnace Exhaust Smells Like Gas – Expert Tips

Ensuring that your HVAC is running optimally is crucial for the comfort and safety of your home. However, issues in the system might still occur. For instance, it’s quite common to hear someone say that their furnace smells like gas.

Is this normal? 

Well, it depends on several factors. The important thing is that when you notice a disturbing gas smell from your furnace, you don’t ignore it. Immediately turn the system off, and call an HVAC expert or your local gas company – it might be serious.

However, not all cases are serious. For this reason, we will look at what causes the gas smell coming from your furnace and what you should do.

Causes of Gas Smell from a Furnace

Generally, most gas furnaces use any of these two gases: propane or natural gas. These gases are naturally odorless but extremely hazardous. 

For this reason, it’s a requirement for gas companies to add some sulfur (which creates a rotten egg smell) to help in gas leak detection. That’s the smell you’ll probably smell from your furnace.

So, what are the major causes of the smell?  And is it dangerous?

1.    Burning Dust

This is one of the most common reasons why your furnace smells like gas when running. But this isn’t a serious one. 

Generally, this will happen if your furnace stays idle for a considerable amount of time. For instance, if you have not been using the house for a while.

When you start the HVAC system again, you might notice the strange smell, as accumulated dust is being burned off. The smell is similar to that of burning gas or rotten eggs.

If this is the case, then you need not worry. The smell will clear after a short period. Cleaning the system after a long time without use is one way of ensuring no gas smell will come from your furnace.

Regular cleaning of the ducts is also recommended. 

2.    Start of Each Cycle

Sometimes you might notice a faint gas smell more frequently, which also disappears fast. This might be a result of the furnace’s kick-on, kick-off cycle.

Typically, a furnace will kick on or off around three to eight times every hour, on average. At the end of every cycle and the start of another, you might detect such a gas odor coming from your furnace.

While this shouldn’t be a cause for alarm, you should also not ignore it. The best thing to do would be to call a technician to inspect the system and diagnose any problems.

3.    Exhaust Pipe

Another cause of the gas smell coming from your furnace might be the exhaust pipe. The exhaust pipe is meant to expel the burnt gas safely to the outside. Therefore, if there is a gas smell in your house, it might mean that the gas is getting back into the house somehow.

However, you should try to pinpoint where the gas is coming from first before concluding this. If the gas is coming through the window or door, then it’s most likely being blown in by the wind from the exhaust pipe.

If the furnace exhaust smells like gas, this is normal and shouldn’t cause any panic. Since the exhaust pipe is used to expel the used gas from the furnace, it might carry some unburned gas that might cause the smell.

The solution here is to note where the gas is coming from and close the door or window next to it.

However, it’s always good to call a professional HVAC technician to inspect the cause. Despite having a clue of why your outdoor furnace vent smells like gas, it’s always better to be safe than sorry. 

4.    Trash or Compost

Sometimes, the issue might not even be on your furnace. Maybe it’s that trash pile you’ve left unattended in your backyard. That’s right!

If you have some trash or compost near your living room window, it might be the cause of the gas-like smell. As the trash decomposes, the smell might resemble that of rotten eggs. When blown into the house by the wind, it’s possible to confuse it with a leaking gas furnace.

So, before coming into a leaking gas conclusion, ensure it’s not some leftovers from the trash causing it.  Make sure that your compost pile is not so close to your window.

5.    Gas Leak

Now, this is what every homeowner dreads. If the gas smell is due to gas leakage, then this should be taken with utmost seriousness.

A gas leak can have very serious consequences if not rectified as fast as possible. For instance, it can lead to carbon monoxide poisoning or even a gas explosion. These two scenarios can cause a lot of damage and sometimes even become fatal.

To detect a gas leak, look for these signs:

  • The constant smell of gas in the house
  • Hissing or whistling noise near your furnace
  • The gas smell from your home’s air vents
  • An alarm from your carbon monoxide detector 

If you notice any of these signs, don’t hesitate. Turn off the system and evacuate immediately. From a safe distance, call your local gas company to come and inspect your HVAC system. 

In addition, when you suspect a gas leak, avoid any activity that might ignite a spark. You never know the extent of the leakage and might cause an explosion.

 Preventing a Gas Leak

A gas leak can be pretty serious. Consequently, serious measures should be put in place to prevent it and detect it as fast as possible when it occurs.

The two most effective preventive measures here include:

  •  Furnace Maintenance

Regular maintenance of your furnace is the first step toward a healthy HVAC system. Maintenance ensures that every part of the system is running well, and inspection is done to identify any issues as early as they occur.

A healthy HVAC system not only offers ultimate comfort for your home but also prevents damages to the property and your family.

  •  Carbon Monoxide Detector

Having this detector in your home is the best way to detect the presence of carbon monoxide in the household.

Remember, the burning fuel in the furnace produces carbon monoxide. As the gas is odorless, a detector will come in handy.

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