Why Is My Furnace Filter Black?

Have you ever pulled your furnace filter out to examine its cleanliness and discover that it is black? Filters can become gray in color when filled with dust and debris; however, if you pull out a black filter it should raise a red flag.  Accumulation of black on your filter could mean a number of things currently going wrong and should definitely be checked by a trusted and professional HVAC technician.  The following list below shows indicators of a black filter:

  1. Mold: with anything else, if something is left wet or damp—mold can begin to form. Leaving an area moist for an extended time can cause the mold to make its way onto the furnace filter. When you see black mold within your system this is certainly a red flag to pick up the phone and have a professional check out the problem and examine the cleanliness of your ductwork.
  2. Poor ventilation: if there are leaks in your ventilation system it can cause soot to leak from these areas and make its way into undesired locations within your system.
  3. Candle/Fireplace soot: if you are a candle guru who loves to burn candles at all available times of the day you’re most likely putting an excessive amount of soot into the air. This soot can collect on interior walls and furniture. If you believe this to be the case in your situation let up a bit on the candle burning and see if you notice a difference on your filter.
  4. Lack of maintenance: it’s recommended to have bi-annual maintenance performed on your furnace for winter and on your A/C for summer.  By keeping up with routine maintenance on your HVAC system you can help to prolong its lifespan, catch repairs before they become emergencies and gain peace of mind!
  5. Clogged burners: as previously mentioned, routine maintenance is important. One part of the routine maintenance will be cleaning the burners. When maintenance is neglected this area of the furnace can become clogged causing soot to form on your filter.

Aside from the 5 indicators above there are several other reasons your filter has turned black. If you are experiencing issues with your furnace it is best to have a trained professional further examine the problem at hand.

For any HVAC or plumbing repairs, installations, indoor air quality, architectural metal or pest help the BELOMAN is here to save the day! Believe in the BELOMAN way!  We’re the only HVAC and plumbing company in the Metro East to receive the 2016 Better Business Bureau TORCH Award. The award honors excellent commitment to customer service through exceptional standards for ethical business practices.