Why the Funny Smell When the Furnace Turns On


HVAC equipments have a way of communicating problems within them and if you are keen enough, you will spot most of them along the way. Furnaces for instance tend to display signs such as the pilot light going off or smell coming from within it when the heat is turned on. There are many reasons behind a smelly furnace from a dirty filter to a broken electronic component or clogged chimney.

It is not advisable to ignore such foul smells and the best approach is to find the source of the smell so as to avoid costly repairs in the long run.

Causes of Musty Smells

The first time you turn on your furnace, you may notice the smell of burning dust. It usually smells much like a damp basement or dirt. The reason behind this is that dirt and dust collect in the ductwork and when the furnace is turned on, this dust gets blown around the house. When this smell persists through the heating season, the pointer could be you need a filter change.

When the furnace is not used for a much longer period, the heat exchange serves as a dust collection point as well as the ductwork. Immediately you turn on the furnace, the dust will burn off and release a musty odor. This smell should not cause much of a concern because within a few hours, it disappears.

Musty odors can originate from mold that is trapped in the humidifier filter or furnace filter. Ensure the filter is inspected and replaced or cleaned depending on its type.

Electrical Burning Smell

Smells such as those of burning electrical parts or plastic are not strange to furnaces. Objects stuck in the ductwork can be the source of these smells when they get overheated. Child toys that are accidentally dropped in the register may also be the reason behind this smell. It is important you visually inspect the registers and even remove them so as to check for spills in the ductwork. Cracked heat exchangers or overheating furnace motors call for the attention of an experienced technician to inspect and sort the problem.

Smell of Oil or Smoke

Oil furnaces are fitted with oil filters. Whenever these filters get clogged, they may emit the smell of oil when the furnace is turned on. You have to locate the filter and change it if this smell is to go away. Smoke smell may be caused by a blocked chimney. Whenever the chimney gets clogged, it sends the smoke back into your furnace and through the ductwork into your home. There are chimney specialists who can inspect and switch your chimney thereby removing the blockages.

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