Residential Plumbing & HVAC Experts

Furnace Odor: What it Could Mean

If you notice a strange odor from your furnace, don’t ignore it. While it could be something as simple as collected dust in the HVAC system or a dirty filter, an unusual furnace smell may also signal a more serious or even dangerous situation. Read on to learn the cause of common furnace odors and what to do about them.

Musty or Earthy Odors

Musty or earthy odors are often caused by a dirty and contaminated air filter or mold and mildew development on the evaporator coil and/or air ducts. Check your air filter first. Change or clean it as needed.

The reason that mold and mildew commonly grow on the evaporator coil and inside air ducts is because of the presence of condensation and food source (e.g. organic matter in the air). Servicing and cleaning the evaporator coil and air ducts should be left to your HVAC professional.

Sewer-like Odors

The evaporator coil collects an excessive amount of condensate during the cooling months. This means that your furnace or heat pump needs a drainage system to remove the water. During the heating months, if the water in the drain trap evaporates, foul sewer-like odors may seep up through the line into the HVAC ductwork and circulate through your home.

Pour a quart of more of a 50/50 bleach and water solution into the condensate pan. The bleach will kill microorganisms in the drain line. Pour another gallon of fresh water into the pan to flush out the system and allow water to collect in the trap.

Rotten Eggs

The smell of rotten eggs is one odor you don’t want emanating from your furnace and air vents. This odor indicates a natural gas leak. While natural gas is odorless, a chemical is added to give it a smell often described as rotten eggs. In this emergency situation, you should exit your home and call 911 for assistance.

If you need help identifying and remedying the source of your furnace smell, please contact Sherlock Plumbing, Heating & Air today. We serve residents of San Diego, Oceanside, Del Mar and all surrounding areas.