How common are furnace explosions?

Author: Mrs. Macy Nikolaus  |  Last update: Tuesday, September 23, 2025

The modern gas furnace is much safer than electric space heaters, and furnaces are built to high safety standards. Although it is possible for a gas furnace to either catch fire or explode, it's highly unlikely. If there is a danger of this happening, the furnace will usually simply shut off—as it's designed to.

What would cause a furnace to explode?

A furnace explosion is usually the result of ignition and instantaneous combustion of highly flammable gas, vapor, or dust that has accumulated in a boiler. The effect of the force from the explosion is often much greater than the boiler combustion chamber can withstand.

When should I worry about my furnace?

You should be concerned if your furnace makes strange noises, blows cold air, cycles on and off frequently, or significantly increases your heating bills. Also, if it's over 15 years old and requires frequent repairs, it may be time to replace it.

How do I make sure my furnace is safe?

Gas Furnace Safety
  1. Have your furnace cleaned and checked every year by a NATE-certified technician. ...
  2. Install a carbon monoxide (CO) alarm in your home.
  3. Change your furnace filter regularly. ...
  4. Keep the area around your furnace clean and unobstructed.
  5. Keep the burner area of your furnace clean.

How often do furnaces catch fire?

As reported by the National Fire Protection Association (NFPA), heating systems like furnaces are a leading cause of home fires, causing almost 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage every year.

Explosions During Furnace Ignition - Symptom of Bad Heat Exchanger

Is it OK to leave furnace on all the time?

During the coldest days in winter, it is normal for a furnace to run almost constantly to keep the home warm. As long as the furnace is running efficiently and not making strange noises, the constant operation is likely nothing to worry about. But in general, your furnace should not constantly be running.

How does a furnace fire start?

Overheated Parts

Any overheated component of a furnace can cause the motor to overheat. This excessive heat then creates ideal conditions for a furnace fire.

Are modern furnaces safe?

Modern furnaces have safety features, including a flame rollout switch, a high-temperature limit switch and furnace flame sensors to help keep your home safe.

How do you know if your furnace is emitting carbon monoxide?

Warning Signs of a Furnace CO Leak
  • Heavy condensation on the windows (found in the room with your furnace)
  • Yellow or brown soot-like stains found around your furnace.
  • A yellow pilot light (instead of a blue flame)
  • Stuffy indoor air.
  • The smell of gas/burning.
  • The pilot light constantly blows out.
  • Rust found on the vent pipe.

What fails first on a furnace?

If the flame sensor fails, your furnace may not be able to start or may shut down shortly after starting. Common causes of flame sensor failure include corrosion, dirt buildup, or a broken wire. The gas valve controls the flow of gas to the furnace. If the gas valve fails, your furnace won't be able to produce heat.

What is the average life of a furnace?

How long does a traditional furnace last? An average furnace is designed to operate for 15 to 30 years in a home. The easiest way to increase the life cycle of your furnace is to hire a certified technician to perform maintenance and repairs once a year.

How do I know if my furnace is overheating?

Watch for the following signs that indicate your furnace is overheating.
  1. A constant burning aroma.
  2. A strange humming noise.
  3. The furnace turns off before finishing a cycle.

What is considered a furnace emergency?

Losing your home's heating is considered an emergency when it's 40 degrees or colder outside. Within just a few hours, a lack of heat can cause indoor temperatures to become uncomfortable and ultimately unhealthy, especially for the young and elderly or those with underlying health conditions.

How common is a furnace explosion?

Although it is possible for a gas furnace to either catch fire or explode, it's highly unlikely. If there is a danger of this happening, the furnace will usually simply shut off—as it's designed to. Regular maintenance will further reduce this already unlikely event.

What is the most common problem of furnace?

Check and Change Your Clogged Filter

This is a simple but essential part of furnace maintenance. One of the most common reasons to have a furnace not working is a clogged filter. It also happens to be the easiest maintenance chore.

What does it mean when your furnace pops?

Homeowners often notice a popping sound when the furnace begins a cycle. This is due to warm air that hits the cold metal of the ducts, which causes expansion and produces that noise. When the popping noise is louder, your gas furnace's burners may be dirty.

What are two warning signs of carbon monoxide poisoning?

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO, it can make you pass out or kill you.

How much does a new furnace cost?

You should expect to spend between $3,800 and $12,00 on a new furnace, including both the unit and installation costs. Factors influencing the price include the type of furnace (gas, electric, or oil), the unit's efficiency rating, and the complexity of the installation.

Does turning off furnace stop carbon monoxide?

Your furnace needs to be on to burn fuel that releases CO. However, carbon monoxide can travel throughout your home via your HVAC system, so it can still create a dangerous situation even when your furnace is off.

What is the safest type of furnace?

There are some factors that play into their levels of safety, however. An electric furnace does not burn any fuel, so it will not have the same problems as a gas-powered furnace. The risks that stem from using an electric furnace include short circuiting and electrical fires.

How do I know if my furnace is safe?

Here are ways you can detect that your furnace has a safety malfunction.
  1. Your carbon monoxide detectors go off. You must have carbon monoxide (CO) detectors in your home if you use natural gas in any capacity. ...
  2. Strange odors. ...
  3. Changes in the color of the burner flames. ...
  4. Loud, persistent clicking sounds. ...
  5. Signs of corrosion.

What is a safe level of carbon monoxide from a furnace?

It's normal for most modern furnaces to have a CO level of less than 50 PPM in the flue, and older natural draft units can safely skate by with levels as high as 200 PPM. However, a furnace with CO levels higher than 200 PPM in the flue should never be in operation without being adjusted or repaired first.

How common are furnace fires?

As reported by the National Fire Protection Association (NFPA), heating systems like furnaces are a major factor of home fires, leading to almost 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage each year.

Why do house fires happen at night?

Why do house fires happen at night? House fires usually occur during the evening hours when people are asleep. The main cause of house fires is electrical malfunctions.

When should a furnace kick on?

Most furnaces kick on and off between three to eight times an hour, depending on things like outdoor air temperatures, the furnace's age, and how much insulation you have. That's why, instead of asking how often a furnace should cycle, it's best to stay alert to changes in how your furnace is running.

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