Why Does My Heater Smell Burnt? 7 Things to Check

The temperatures outside have dropped, and your heater is on full blast. But wait, what’s that smell? Why does your heater smell burnt? While some burning smells from a heater are natural after a long summer with the unit sitting unused, they can also be a sign of serious trouble in less common cases. Here are seven reasons for a heater that smells burnt and what to do next when your heater smells like someone left the rolls in the oven for too long.

1. You’re Turning On the Heater for the First Time of the Season

When the heater sits unused from spring to fall, it accumulates dust. So when the temperatures drop come winter, the heater will burn up that excess dust, leading to a burning smell.

Although an initial burning smell from a heater that’s just been turned on shouldn’t cause any problems, you can help avoid the smell by keeping up with regular furnace servicing and cleaning. Call in a pro to deep-clean and inspect your furnace in the fall so that it’s ready to run in winter—no burnt smells included.

2. The Air Filter Is Dirty

Many furnace problems, including a smelly furnace, stem from dirty air filters. When the furnace filter is filled with dust and dirt, it puts more strain on the rest of the heating system. This can lead to overheating and a burning smell, especially if parts wear out.

It’s important to change your air filter regularly, every 30 to 90 days, depending on the type of air filter your furnace uses. If you can’t remember when you refreshed the air filter, it’s probably time to change it and see if that stops the burning smell.

3. The Vents Are Dusty

Similarly to dusty air filters, your vents can also get clogged with dust and other debris that can smell burnt when hot air blows through the ductwork. Make sure to clean vent covers once per month, and hire a pro to inspect and clean your air ducts once every three to five years.

4. Something’s Stuck in the Vents or Heater

If the burning smell is accompanied by the smell of plastic or rubber, it likely means there is something lodged in your air vents or in the heater itself. As the hot air blows through the system, it can start to melt or burn the stuck object.

You can check the vents around the house to look for a toy or other object stuck in the vents, but it’s still safest to have a furnace pro come check out the problem.

5. Electrical Wiring Is Damaged

When you smell a burning odor coming from the heater, it could be an electrical issue. Is your furnace fan running with the thermostat off? Do you hear buzzing sounds while the furnace is on? These are additional signs that there could be damage to the heater’s electrical wiring.

Damaged wiring presents a risk of shock or electrocution, so don’t attempt to fix the electrical issue yourself. Call in an electrician or furnace repair pro immediately if you suspect electrical damage.

6. The Exhaust Vent or Chimney Is Blocked

The heater’s exhaust vent or chimney flue is responsible for carrying harmful combustion gases, like carbon monoxide, outside of the home. But if the heater smells burnt, or if your furnace smells like gas, it could be a sign that the exhaust vent is blocked or damaged.

If you suspect that exhaust gases are leaking into your home, shut off the heater immediately, head outside, and call a pro in for an emergency repair.

7. The Heater Is New 

Sometimes, the burnt odor you’re smelling isn’t a serious flaw but just a sign of a new heater. When you turn on a new heater for the first time, the chemicals from the manufacturing process may produce a burning smell for a few hours or up to a few days. If the smell worsens or persists for longer, call in a pro to inspect the furnace and check for the source of the problem.

What to Do If Your Heater Smells Burnt

There are several different issues that can cause a heater to smell burnt. While some are innocent, like the summer dust burning off the heater as it warms you on the first cold day of winter, other issues should cause more concern.

Problems like faulty electrical wiring or a blocked chimney can lead to serious hazards, like shocks, electrocutions, electrical fires, or carbon monoxide leaks. If you’re wondering why your heater smells burnt all of a sudden, it’s time to call in a local furnace repair pro ASAP to figure out what’s going on.

How to Prevent a Burning Smell in Your Heater

Regular furnace maintenance is the top way to prevent burning smells or other unpleasant odors from your heater. Here are some maintenance tips to keep your furnace in good, odorless condition:

• Change the furnace filters regularly—every 30 to 90 days.

• Schedule annual inspections and furnace cleanings.

• Keep 30 inches of clear space around your furnace.

• Check vents monthly for dust, objects, and other debris.

• Regularly dust and vacuum your home to minimize dust buildup in the heater and vents.