If you turn your furnace on for the first time this fall and suddenly smell something burning, there is a good chance you are simply smelling dust that has accumulated inside the heating system during the spring and summer.
This is very common when a furnace has not operated for several months. As your furnace heats up, dust that has settled on the burners, heat exchanger and other internal components begins to heat and burn away. The odor can travel through your ductwork and come out of the registers throughout your home. In most cases, the smell should begin fading fairly quickly and disappear after the furnace has been running for a while.
When a burning smell from your furnace is normal
A normal first-of-the-season furnace smell is usually best described as dusty, dry or slightly smoky.
It often happens:
The first time you use your furnace in the fall
After the furnace has been off for several months
For a relatively short period after the furnace starts running
You may notice it more strongly near the air registers when the blower begins circulating warm air. You should also check your furnace filter. Starting the heating season with a clean filter helps maintain proper airflow and keeps accumulated dust and debris from circulating through your heating system.
How long should the burning smell last?
If accumulated dust is causing the smell, it should gradually become weaker as the furnace operates.
Depending on how much dust has accumulated, you may smell it for anywhere from several minutes to a few hours. What you should not experience is a burning odor that continues getting stronger, returns every time the furnace operates or persists long after the furnace has warmed up. Those symptoms deserve a closer look.
When a burning furnace smell could mean trouble
Not every burning smell should be dismissed as dust. Pay particular attention to what the odor actually smells like.
Burning plastic
A melting or burning plastic smell can indicate an overheating electrical component, wiring problem, blower motor problem or another part becoming excessively hot. Turn the furnace off and have it inspected rather than continuing to operate it.
Electrical or burning-wire smell
An electrical burning odor is also different from the dusty smell you might notice during the first heating cycle of the season. If something smells like overheated wiring, insulation or electronics, shut the furnace down and call for furnace repair.
Smoke
You should not see smoke coming from your furnace or registers. If you see smoke or have reason to believe something is actually burning, shut the system off and address the situation immediately.
What if I smell rotten eggs instead?
A rotten-egg or sulfur-like smell is not the normal smell of dust burning off a furnace. Natural gas is given a distinctive odor so leaks can be detected. If you suspect a gas leak, leave the house and contact your gas provider from a safe location. Do not operate switches, appliances or anything else that could create a spark while you are still inside.
The first furnace startup is also a good time to pay attention to how it runs
When you turn your furnace on for the first time this season, don’t just pay attention to the smell.
Listen to it. Is the furnace making noises you don’t remember hearing last winter? Is the blower running normally? Is warm air reaching every room? Does the furnace start and stop repeatedly? Is it taking unusually long to warm the house? Small problems that developed while the system sat unused can become much more noticeable once cold weather arrives and your furnace begins operating every day. If something doesn’t seem right, having it checked early can help you avoid discovering a furnace problem on one of the coldest days of the year.
When you need furnace repair?
If the burning smell disappears shortly after the first furnace startup of the season, accumulated dust was probably the cause. If the smell continues, gets stronger, smells like burning plastic or electrical wiring, or comes back every time the furnace runs, don’t ignore it.
Roberts Brothers Comfort can inspect your furnace, determine what is causing the odor and make any repairs needed to get your heating system operating properly before colder weather arrives. We provide expert furnace repair service in Casstown, Covinton, Fletcher, Piqua, Rosewood, Saint Paris, Sidney, Tipp City, Troy, Urbana, West Milton and all the surrounding areas in the Miami Valley.
