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Weird Smell Coming from your 


Weather getting cooler? Turning the heat back on for the first time? As a company dedicated to making sure your HVAC is running smoothly year round we believe it is important to recognize when it is time for some maintenance. Unfortunately the signs can sometimes come in the form of unpleasant smells. So here are a few smells to watch out for and what they could mean.

 1. Burning Dust

If this is the first time you are turning on your furnace or heating system after the summer it is possible that dust has settled on or inside the system. When the furnace is turned on the dust will burn off creating a mild burnt smell. This smell should wear off after an hour or two with no serious damage, however if it persists call your technician. 

If the smell lasts longer it could be due to a clogged filter or a build up of debri within the components of the furnace. If you switch out or clean your filter and the small continues call an HVAC technician ASAP.

2. Plastic or Electrical Burning 

A plastic, electrical or metallic burning smell can often signal that your furnace is overheating. The smell could mean that wires within the components of the furnace are melting or burning. To avoid starting a fire or damaging the furnace turn the heat off immediately and call an HVAC technician. 

In the case of smoke it is better to be safe than sorry. Turn the system off and call your technician immediately!

3. Chemical Smell

A chemical smell coming from your vent could be the result of a cracked heat exchanger. If you smell chemicals your system could be at risk of fire or a carbon monoxide leakage. Either way it is best to shut the system off, get out of the house immediately and call your service tech to check it out. 

In this case even if you aren't completely sure that it is a chemical smell it is still important to have a professional check it out. This is potentially one of the most dangerous smells that could come from your vents so please be cautious.

4. Rotten Eggs or Sewage

Rotten egg, Sulphur or sewage smells are often attributed to natural gas leaks so it is best to shut the system off, leave the house and call a professional to repair it. Natural gas leakage can cause you to feel dizzy, light headed or nauseous so its best to call someone immediatly if you smell sulphur.

It is also possible that a strong sulphuric or sewage smell could be caused by a sewage leak in pipes near your duct work. In this case a plumber will most likely need to take a look as well.

Because these smells can be very similar but have different causes it is still good practice to have an HVAC tech rule out a natural gas leakage just to be on the safe side. You dont want to be wrong about this one!

5. Rotten Garbage or Decay

It is possible for small animals or birds to find their way into your HVAC systems and get stuck. If it is very obvious that the smell is caused by a deceased critter you are most likely not in danger but should definitely have the remains removed. If they are in an easily accesible place you may be able to do this yourself but if you feel more comfortable leaving it to the pros we are happy to help.

6. Musty or Moldy 

If you live in an area with a lot of humidity or your house is prone to mildew or mold it is possible that mold can also be growing in your furnace system. If you smell a mildew or moldy aroma when your turn on your furnace you most likely need someone to come find the source of the dampness as well as maintenance your heating system. Because mold can often be the result of a plumbing issue we suggest that this be addressed as soon as possible to avoid any damage to your houses structure.

Bad Smell Warning!

It can be difficult to distinguish between different types of smells, even the very harmful ones. For your safety, our suggestion would be to always have a professional check it out. Just remember that a well fuctioning and well maintained HVAC system should not be putting out ANY unpleasant smells. Anything stronger or more potent than a mild dusty smell when you turn your furnace on for the first time should be handled with the utmost caution and care.

Whatever unpleasant aroma you may be sensing please remember to always go with the safest option. If you are unsure it is always best to call someone to check it out. While a mild dusty smell could just be the dust burning off of your furnace you also dont want to take any chances of mistaking a certain smell for the wrong thing. If you arent completely sure please give us a call.


We are always here to help even if just for your peace of mind!

Sources and References

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