(602) 842-0009

All Articles

4 Weird Smells You Might Get When You Turn On Your Heat

Man smelling something weird

Worried about the weird smell coming from your AC?

Updated April 2024

After months of inactivity, it’s not uncommon for your heating system to put off a slightly unpleasant odor the first time you turn it on. All the more so if you haven’t yet had a heating tune-up.

That said, it’s important to investigate the source of the smell. Otherwise, you could risk a potentially expensive repair down the road.

To help you troubleshoot, we’ll review four weird smells you might get when you turn on your heat below:

Then, we’ll discuss how to remedy each problem— including how professional heating maintenance can help you avoid weird smells altogether.

Need a heating repair or tune-up?

Give the pros at George Brazil a call today at (602) 842-0009. We train our licensed and skilled technicians to service all types and brands of heating systems, and we have hundreds of 5-star reviews from fully satisfied customers!

Burning Smell

A close up picture of a dirty air filter

A burning smell from your furnace can come from dust buildup or dirty filters.

Does it smell like something is burning when you turn on your heat? A burning smell is pretty common and tends to be caused by these factors:

  • Dust and dirt buildup on the heater: During the summer months, it’s normal for dust and dirt to accumulate in and around your heating system from lack of use. When you first turn on your heat for the season, the dust and dirt will burn off, creating a burning odor.
  • Clogged air filters: Your heating system’s air filter captures dust, dirt, and other airborne particles. So if your air filters are clogged, you’ll have even more dust and dirt buildup that will burn off when you turn on your heater.

How to fix:

Man performing maintenance on a heater

Get a heating tune-up to prevent any burning smells.

Get a professional heating tune-up before the start of the heating season. When a trained HVAC pro inspects your equipment, they’ll have a chance to clean any dust or dirt buildup.

They’ll also let you know if your air filters need cleaning or changing. If the filters stay clogged for too long, the imbalance of airflow can create problems like system breakdowns and increased energy costs. So to avoid a burning smell and increased out-of-pocket costs, it pays to invest in heating maintenance.

Mechanical Odor

If your heating system is putting off a mechanical (or electrical) smell, you may have a more severe problem, such as frayed wiring or a failing motor.

With age and normal wear and tear of your system, these events can happen. It’s also why most newer models have built-in safety features that will cause an automatic system shutdown if an electrical malfunction occurs. However, you’ll want to get it looked at straight away. Otherwise, you could risk a system breakdown— or worse, an electrical fire!

How to fix:

Schedule a repair diagnostic immediately. You’ll want a trained HVAC technician to perform a thorough inspection of your heating system. That way, they can uncover the source of the problem and get it repaired before you incur significant damage.

At George Brazil, we offer same-day repair appointments and even waive the service call fee if you choose to hire us for the repair!

Chemical Scent

You could have a cracked heat exchanger if you smell a strange chemical scent.

No matter what type of heating system you have (furnace, boiler, heat pump, etc.), the heat exchanger is its "heart" because it creates the heat. The system emits toxic gases like Carbon Monoxide as a byproduct during the combustion process. Manufacturers house the heat exchanger in a protective chamber to keep those poisonous fumes away from your air.

However, a cracked heat exchanger will allow those gases to escape into your home, circulating a fishy and chemical odor.

How to fix:

Schedule a heating repair ASAP. Combustion fumes are a health and safety hazard, so even if you don’t end up having a cracked exchanger, you’ll have peace of mind that your household is protected.

Heat exchangers are a costly replacement (anywhere from $2,500-$6,500), but their replacements typically have warranty coverage. That said, most manufacturers require once-a-year professional heating maintenance to keep your warranty valid. So to avoid paying out of pocket, it’s wise to invest in annual heating tune-ups.

At George Brazil, our maintenance plan includes friendly automated service reminders, so you never have to worry about losing your warranty. You’ll have peace of mind that your equipment is operating safely and efficiently for the whole heating season!

Rotten Eggs

A rotten egg smell comes from gas furnaces since heat pumps use electricity. If you smell this odor, you need to leave your home immediately as you have a life-threatening situation on your hands.


Natural gas is toxic and also odorless. Suppliers will add a methyl mercaptan chemical into the gas to help homeowners detect a gas leak. The chemical smells like—you guessed it—rotten eggs, and it's foul because manufacturers want you to know that you have a gas leak.

How to fix:

If you suspect a gas leak, exit your house immediately. Then, call 911 or your local gas emergency hotline. In Phoenix, the phone number is (602) 271-4277.

Man performing maintenance on a heater

Schedule a gas leak repair if you smell rotten eggs when you turn on your heat.

Once your household is safe and far away from the leak, contact a qualified HVAC technician to inspect your heating system for repairs. At George Brazil, we offer 24/7 emergency service. Just call us at (602) 842-0009 for immediate assistance. We’ll get your heating system fixed in no time!

Need trustworthy heating services in Phoenix?

George Brazil has you covered. Our trained technicians will work fast and efficiently to resolve your heating problems, from heating repairs and maintenance to new installations. Backed by more than 65+ years of experience and thousands of happy customers, it’s no wonder we’re one of Phoenix’s most trusted HVAC contractors.

Learn more about what to expect when you hire us by reading the following pages:

Call us today at (602) 842-0009 or click the button below!

Related Articles