Common Furnace Gas Leak Symptoms

Furnace gas leak symptoms

Natural gas furnaces hold the title of being the most prevalent furnace type in the United States, powering 48% of all households. The utilization of natural gas gives them the ability to heat. Despite the low failure rate of its modern counterparts, it is nevertheless vital for homeowners to understand how to spot a gas leak. In this article, we’ll discuss four red flags about your furnace gas leak symptoms.

1. The Stench of Sulfur:

Although pure natural gas is naturally odorless, manufacturers use chemicals called mercaptans to provide a distinctive stench to identify leaks—an odor frequently compared to sulfur or rotten eggs.

Check your furnace if there is a persistent and unexplainable sulfur odor in your home. Your home’s air vents could give out a slight mercaptan odor. If there are large leaks, the stench might only be detectable just next to the furnace.

2. Hissing Noise:

The pipes in homes and the heat exchangers in furnaces are pressured with natural gas. The pressure of the gas that is escaping when there is a leak causes the recognizable hissing sound. It’s best to switch off the furnace in order to hear this sound because the fan motor’s hum can mask the hiss.

Use the soap test if you hear a hissing sound but cannot place its origin. The exposed gas pipes next to the furnace and heat exchanger should be cleaned with a cloth dipped in soapy water after the furnace has been turned off. In the soapy water, bubbles will appear wherever gas is escaping.

Also, Read: 5 Common Furnace Problems That Are Reported By Homeowners

3. Dying Plants:

Natural gas can not by itself make plants toxic, but it can have a disastrous effect on their development by reducing soil oxygen and boosting the creation of hydrogen sulfide gas. This gas prevents nutrients from reaching the roots of plants, which results in scant development and eventual death.

If you use a gas furnace, keep an eye on the health of your indoor plants because gas leaks might be harmful to them. Gas escaping and injuring the grassroots by reaching the soil surface typically manifests as wilted or dying indoor plants and patches of dead grass on your lawn.

4. Health Concerns:

Carbon monoxide, which prevents blood cells from carrying oxygen throughout the body, is the main health risk associated with natural gas for living things. Flu-like symptoms, including headaches, weariness, eye and throat irritation, and nausea, can be brought on by gas leaks. Dizziness, confusion, and even unconsciousness and death can result from more serious exposure.

It’s important to remember that pets may show symptoms earlier than people since they are more susceptible to gas exposure. Take urgent action if you see any strange behavior in your pets, such as lethargy, vomiting, or trouble walking. Get everyone out of the building and call your gas provider to have technicians come and check for leaks.

Physical Symptoms Associated With Gas Leaks:

Prolonged exposure to an unattended gas leak in your Somerville home can put you and your family at greater risk of a number of health problems, such as:

  • Trouble breathing
  • Increased sleepiness or exhaustion
  • Flu-like symptoms including headaches and nausea
  • Ear, nose, and throat irritation
  • Mood swings, including sadness
  • Nasal bleeding
  • Tinnitus
  • Loss of appetite
  • Chest pain

Gas leaks can harm animals, resulting in bewilderment, drowsiness, and vomiting

Also, Read: Why Is My Furnace So Loud And How Do I Fix It?

What To Do If You Have A Gas Leak In Your Home:

Gas leaks provide a serious risk, so you must act right away to protect your family. The steps below should be taken if you believe your home has a gas leak:


Assemble all family members and pets, then quickly exit the house with all doors open.

Dail 911:

Once you are outside and safe, dial the emergency number for your local fire department, your utility provider, or both for prompt assistance. Don’t use your home phone since it can set the gas on fire.

Hold on:

A licensed inspector will arrive to find and fix the gas leaks, making it safe for you to go home again. Once you’ve been given the all-clear, only go back home.


The safety of everyone in your home depends on your ability to recognize and react to indicators of a gas leak in your furnace. Keep in mind these red flags and get in touch with experts as soon as you suspect a furnace leak or other problems.



How do you identify a leak in your furnace?

Keep an eye out for soot stains or a brownish-yellow discoloration near the appliance that is dripping. Additionally, you might smell sulfur, hear hissing or whistling close to a gas line, or observe a white or dusty cloud building in the water.

What indications of a gas leak are most typical?

An odor of sulfur or rotten eggs, a whistling or hissing sound, or bubbles in the water can all be found close to gas lines.

Is the gas coming from the furnace odor normal?

Gas smells near furnaces are uncommon unless there is an issue. Even a slight gas odor when the appliance is running should be checked out occasionally.

Can my gas furnace cause carbon monoxide poisoning?

It can, really. Burning furnaces that use gas or oil produce carbon monoxide (CO), an odorless, deadly gas. To avoid CO leaks, make sure your furnace receives regular maintenance.

Does opening windows allow carbon monoxide to escape?

Although it can assist, opening windows won’t completely get rid of carbon monoxide. Since most windows don’t offer enough ventilation, it could take several hours for CO to entirely disperse.

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About the author


I am Ben , a seasoned HVAC specialist with over 6 of experience in the HVAC industry. I holds HVAC Certification and has a proven track record in providing expert advice on HVAC systems.