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Help! My Heating & AC Smell Terrible

If you’re smelling something unpleasant from your HVAC system, it’s important that you pay attention. While the smell may indicate nothing more than a dirty HVAC system that needs cleaning, it could also be an indicator of a very serious problem. If your heating or cooling system is emitting a foul odor, call Lambert Plumbing and Heating Ltd. and ask about our exceptional HVAC services!

Does it Smell Like Rotten Eggs?

If the smell you are experiencing is something like rotten eggs or sulfur, there may be a gas leak somewhere in your system. Whether the leak is coming from a loose pipe fitting or from a hole somewhere in the line, it should be addressed immediately. Leaking gas can emit extremely dangerous carbon monoxide.

Short-term exposure to natural gas and carbon monoxide in your home can result in:


  • Headaches
  • Nausea
  • Vomiting
  • Dizziness
  • Blurry vision
  • Upset stomach
  • Exhaustion

The longer you are exposed to gas and carbon monoxide, the worse the symptoms will become. If not addressed, carbon monoxide exposure can be deadly. If you smell a sulfur-like smell from your HVAC system, open all the windows in the house to disperse the gas, leave your home immediately, call your gas company to have the gas supply shut off, then call Lambert Plumbing and Heating Ltd for gas line replacement.

Is it Old And Musty?

“oldsmell”Simply put, that musty smell means that you have a mold problem in your HVAC system. Not to worry, though, the issue can usually be resolved relatively easily. If the mold is present in the system itself, it’s probably due to a blocked drain pan.

You can unclog the drain pan yourself, and have the unit cleaned by a professional. You can also request a duct cleaning to remove any mold that may be developing in your air ducts or vents. If you have already had your unit and vents cleaned, and the musty smell persists, your AC unit may be too big for your home.

This causes the air in the house to re-enter the unit before it has been adequately dehumidified, allowing excess moisture into the unit. In this case, call Lambert Plumbing and Heating Ltd to see about installing an appropriately sized unit.

Is Something "Burning?”

The burning smell coming from your HVAC system could be caused by a few different things going on within your system. Let’s take a look at what might be “burning”, based on what you’re smelling:


  • If your heater smells like it’s burning the first time you’ve turned it on in months, the smell is probably coming from dust that has settled on the heat exchanger since you last used it burning off. If this is the case, the smell will go away after a few minutes.
  • If you are smelling something like burning rubber, it could be that your HVAC system uses a belt-drive blower, and rubber bands or belts are becoming burnt out. Simply replacing them with new belts should take care of the problem.
  • If you smell burning plastic, you may have an electrical problem within your system. The smell comes from the protective plastic casing on electrical wires. Call an HVAC service company like Lambert Plumbing and Heating Ltd right away to check for short-circuited wires, loose screws, defective breakers, and worn out connections.