Why Do I Smell Gas When My Furnace Kicks On?

Though natural gas and propane don't smell, gas companies often include unpleasant additives resembling rotten egg smells to alert people of possible gas leaks in their homes. So if you detect something foul when you turn on your heater, you might ask, "Why do I smell gas when my furnace kicks on?" 

At Watson Heating & Air, we offer comprehensive furnace repair in Richmond, KY, so we understand how confusing it can be to smell gas odors. As a top HVAC company serving the area, we can explain why the situation occurs and the best steps to take to prevent living with a potentially hazardous furnace. When you need immediate help, call us at (859) 625-0081.

Gas Smells From Dust

People often ask, "Why do I smell gas when my furnace kicks on?" at the start of the winter season when they need their heating system to combat cold temperatures. That's a normal occurrence and usually doesn't indicate a problem. 

When gas furnaces lie dormant for several months, dust will accumulate on the equipment. Without proper cleaning before turning on the furnace, the dust can get onto the heat exchanger and burners. So when you fire up the heating unit under those conditions, the gas odor is the system burning off the dust and debris. 

It might take a few hours for the smell to dissipate. You can get fresh air indoors more quickly by opening windows to create cross ventilation. 

Gas Smells From Emissions

It's reasonable for a gas furnace to emit a bit of gas whenever it turns on due to its combustion process. The odor should be faint and disappear relatively quickly.

Lingering gas smells are a problem if they last long after the furnace ignites its burners because that usually means a gas leak is present somewhere in the heating system.

Gas Smells From Gas Leaks

Any time you smell gas outside of using the furnace for the first time of the season or for a few minutes after it kicks on, you need to take immediate action. Gas leaks beyond the trace amount the furnace releases during combustion are extremely dangerous because they can cause a deadly explosion if the concentration gets high enough. A slow gas leak can also kill plants and cause natural gas poisoning in people and pets.

If you're unsure whether you're dealing with a gas leak, consider the following:

• The gas odor is strong and persistent enough to be noticeable right away
• Your gas detector goes off when a leak is present
• The furnace smells like gas and emits a whistling or hissing sound

If you can identify with any of those statements, you need to contact a furnace repair company and your local gas company immediately. Gas leaks are not something you can manage without professional help. 

Best Practices for a Gas Leak

Natural gas and propane leaks are dangerous. Still, both gases have different properties and won't cause the same effects. For instance, propane is more dense than air, so it sinks to low places, but natural gas is lighter than air and is more likely to circulate through a home's ventilation.

As such, natural gas can vent outdoors and reduce its concentration inside your home. However, a propane gas leak will likely remain indoors or around the house's exterior at a high concentration. 

In either case, it's not advisable to smoke, light a fire, or turn on many electrical devices when there's a suspected gas leak. Even turning on a light switch could spark an explosion under the right circumstances. If you must have light, use a flashlight to evacuate your home and call the furnace repair and gas companies from outside. 

How to Prevent a Furnace Gas Leak

A gas leak can develop due to a broken supply valve, cracked heat exchanger, or damaged gas line. As such, routine furnace maintenance is the best way to prevent leaks. A technician will assess your furnace and make repairs and adjustments that could cause a gas leak. 

Contact the Professionals at Watson Heating & Air

Whether you're asking yourself, "Why do I smell gas when my furnace kicks on?" or need to know why your furnace fan keeps running, you can trust Watson Heating & Air to have the answer. As a top-rated HVAC company in Richmond, KY, with over 100 five-star reviews, we proudly offer affordable heating repairs, installation, and maintenance services. 

At Watson Heating & Air, no job is too big or small for our skilled technicians to handle. We guarantee top quality, so call (859) 625-0081 to request an appointment with us today.