When the outside temperature starts to drop, the feeling of your furnace pumping warm air into your home can feel great. What you need to be concerned about is if that warm air is accompanied by an odor. It's a problem you should look into immediately, because it could be due to one of these 4 reasons.

Dust That Is Burning

When a furnace is not being used regularly, dust can easily gather inside the furnace where the main heating element is. Once that heating element becomes hot when turning it on for the first time in awhile, you may smell something that is burning coming from the vents. This problem usually fixes itself within 45 minutes, which is about how long it takes for dust to burn off of the furnace's heating element. Call in a professional if the bad odor continues for longer than that.

Dust In The Air Ducts

For those that do not use central AC, know that dust can collect in the air ducts during the hot summer when the furnace is not in use. This could cause a musty smell to come from the vents when turning on the heat for the first time in the winter. It is not harmful, but it could require air duct cleaning to get the smell to go away, especially after many years of having dust collect in the vents.

Air Filter That Is Dirty

Your air filter is a key part of your HVAC system, since it is what blocks the debris and dirt with odors from traveling through your house. A dirty filter will make it hard for the air to pass through, and when it does, it takes that odor along with it. Dust on the filter can also get to the heat exchanger, and be responsible for causing that burning smell previously mentioned. Stay on top of changing your air filter since replacing it is easy and will prevent potential problems from occurring.

A Gas Leak

Be concerned when you smell rotten eggs coming from your air vents. This means there is a natural gas leak, since an odor is added to the gas so it is easily identifiable in these types of situations. Leave the house, and have a professional HVAC technician look into the problem. A natural gas leak is a serious situation, and ignoring the problem could potentially cause an explosion.