Green Leaf Air

by Rifat A. in Blog, Heating, HVAC Repair & Maintenance, HVAC Tips 1 comment

There can be several reasons why you’re smelling gas near the heating unit. But should you really be worried?


Gas Smell Near the Heating System: Should I Worry?

Effects of Gas Leak

Even a little exposure to natural gas can make you feel lightheaded or sick. When you are exposed to natural gas for a long time, you can become severely sick and can have issues such as pale skin, headaches, dizziness, fatigue, body aches, vomiting, and eye irritation.

Natural gas can harm your pets and houseplants as well. It decreases the O2 level in your home. As a result, your houseplants won’t be able to take more oxygen and eventually, they’ll die. Again, pets usually have lower resistance to gas leaks. If they are exposed to a gas leak for a long time, it can be a life and death situation for them. It’s truer if you have smaller pets like rabbits or cats.


5 Reasons behind Gas Leak from the HVAC System

1.      Idle Heating Unit

As Dallas is hot and humid during the summer, people usually don’t have to use their heating unit for almost half of the year. During this period, dust and other particles start accumulating inside the HVAC system.

When you turn on the furnace after months, this dust can resemble the smell of natural gas. Generally, the smell here is weak, and you can barely notice it. You can eliminate this smell by opening the windows or by ensuring proper ventilation.

However, as soon as you turn on your heating unit and start noticing hissing sound with a strong smell of natural gas, you must leave the house. Because it indicates that your heating unit is actually leaking gas and it requires professional repairing ASAP.

2.      Gas Emission Due to Furnace Cycle

Each time when the heating unit cycles on, it emits a small amount of natural gas. Don’t worry, this emission is normal. However, if you frequently notice the strong gas smell when your heating unit cycles on, you must turn off the unit. Because it indicates that it has a gas leak. As soon as you find this gas leak, you’ll have to call a heating professional and repair it.

3.      Malfunctioning Air Vents

In general conditions, your heating unit will draw the natural gas to the vents and discharge it to the outside air. But when you neglect HVAC maintenance, your heating unit will have backdraft problems. Due to backdraft, natural gas will come back to your space instead of going outside of your house. Thus, your home will get filled with gas and reduce the oxygen level in your house. Besides, when your space is filled with gas, it’ll increase the CO in your home, which is very hazardous, and long exposure to CO can cause severe health issues.

Your heating unit can have a backdraft problem when there are leaks in the ductwork or due to leaky flue. To avoid backdraft, you must do regular heating maintenance checkups by a professional heating technician.

4.      Exhaust Pipes

If you smell gas near the exhaust pipes of your heating unit, you shouldn’t be worried. Because these exhaust pipes expel the unused gas to the outside air. Generally, when the outside air blows back to your house, you can smell natural gas in your home.

If you don’t want to smell gas in your house, you’ll have to close your windows when there is heavy wind outside.

5.      Malfunctioning Heat Exchanger

The heat exchanger plays a significant role in producing heat. However, over time, this heat exchanger can get damaged and start malfunctioning.

When you have a malfunctioning heat exchanger in your heating unit, the produced air will start mixing with the combustion of natural gas and start spreading in your space. As a result, your home will get filled with gas, and the CO level will increase.

If you have an old heating unit and notice a gas smell in your space, you must call a heating professional and check the heating unit ASAP.



If you smell a weak gas smell near your furnace, you won’t have to worry in most cases. However, if the smell is strong and you hear a hissing sound coming from the heating unit, you must turn off the system and call a heating technician.

Green Leaf Air provides heating services in Dallas and its surrounding areas. Call 972-992-5006 to contact our professionals.


See the summary of this content here in an infographic – 5 Reasons Behind HVAC Gas Leak [Infographic]

5 Reasons Behind HVAC Gas Leak
5 Reasons Behind HVAC Gas Leak
Rifat A.

HVAC Expert, Author & Mathematician... rifatahmed.com

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