Many homeowners know that they need to change their HVAC filters regularly. When you swap the old filter for a new one, it will usually be clogged with grey particles. However, some situations may cause the filter to turn black. Should you be worried? In most cases, the answer is yes.
The filter is an essential part of your home comfort system. Heated air from the furnace circulates through it in the winter, while cooled air makes its way through the fibers in warm months. All year long, the filter traps a variety of particles, including allergens, dust, dirt and even viruses and bacteria. When the filter quickly turns black, it’s a sign that something is amiss in your environment. Here are some common reasons for a black furnace filter.
Soot
Soot occurs when combustion systems don’t burn properly. Over time, soot collects on surfaces like walls, carpets, curtains and your air filter. Removing soot from your home is critical because its presence can make you ill. Breathing in soot can lead to lung and respiratory diseases and even premature death. To remove soot from your home’s air, use a carbon-activated filter in your furnace to trap these particles. Air filters clogged with soot can also lead to mold and other allergens in your home. Here are some common causes of soot.
Scented Candles and Fireplaces
If you regularly burn scented candles, they can contribute to a black air filter. These candles don’t burn cleanly because they have a lot of unsaturated oils. If your candle flame is yellow or orange instead of blue, it’s producing a lot of soot. The most effective way to limit soot from candles is to stop burning them, but you can also limit wicks to one-quarter inch in length. Also, keep candles away from vents, fans and hallways.
If you use a fireplace during cold weather, ensure it is adequately vented. You can always expect some soot from an indoor fire, but how much enters your home depends on how you operate it. To minimize soot, keep glass doors and vents open during operation. Remove old, cracked and broken logs, and if you have a gas fireplace, have a professional occasionally inspect the burner and gas pressure.
Forest Fires
Although you can’t control this phenomenon, massive forest fires thousands of miles away can clog your air filter with black soot. If you have an air quality alert due to forest fire smoke that has drifted over Virginia, keep your doors and windows closed as much as possible until the air mass passes. Change the filter immediately afterward to help airflow.
Improperly Operating Gas Furnace
Problems with specific parts of a gas furnace can cause improper burning, leading to soot and a serious situation. Yellow or orange flames coming from the burner indicate improperly burning. Possible causes, including the following:
- Cracked heat exchanger
- Improper venting of combustion gases
- Misaligned or clogged burners
- Dirt or debris clogging gas valves
A furnace that’s improperly burning combustion bases needs prompt attention from an HVAC technician. This situation can lead to flame rollout, where furnace flames leave the unit in search of oxygen.
Improperly Burning Gas Appliances
An incorrect mixture of air and gas can cause this appliance to produce soot. As with other potential problems, check the heater’s burner for yellow flames instead of blue ones, which indicate proper combustion. Have a professional inspect the unit and remedy unsafe conditions like dirty burners, debris blocking the flue and lack of oxygen in the area surrounding the heater.
Black Mold
This organism thrives in moist environments, making furnace filters the perfect breeding grounds. This problem arises more commonly in the summer when you run the air conditioning side of the system. When you run the air conditioning, the evaporator coil becomes damp with condensation. Moisture that mixes with dust and dirt can lead to black mold growth, eventually spreading to the main unit and the filter. Mold growth can also occur in the ducts and other damp areas like basements.
Mold growth can be as dangerous as a gas or carbon monoxide leak. Various types of mold can grow in this environment, especially when the filter is clogged with other debris. Regular furnace maintenance and cleaning, as well as periodic duct cleaning, will keep mold out of your system and block excessive growth. Letting mold get an excessive hold in your home also has expensive consequences. Mold remediation costs many times more than regular HVAC maintenance.
Not all molds that are black in color are the toxic black mold species, Stachybotrys chartarum. Many other species of mold can be black in color and cause respiratory symptoms. This is especially true if you have allergies. If you see mold and are concerned about your health, you can find mold testing kits at most hardware stores. These kits allow you to collect pieces of this mold and send it to a lab for identification. The lab will then send a list of species and the level of health risk they present.
Carbon Monoxide
Carbon monoxide is a colorless, odorless gas, but when it is present in your home at high levels, it can turn your HVAC filter black. Gas-powered furnaces require fire to operate and produce carbon monoxide through the combustion process. High carbon monoxide levels can indicate a problem with your furnace. If you suspect carbon monoxide is the culprit, immediately order a carbon monoxide test to accurately determine whether you have dangerous levels inside your home. You can also purchase combination smoke and carbon monoxide detectors for your home.
When to Call an HVAC Technician
Regularly replacing the air filter inside your HVAC system can help avoid black filter situations. However, the older your furnace is, the more likely something will go wrong with the unit requiring professional repair. Change or wash your filter according to manufacturer recommendations. If you have an older HVAC unit and want to keep tabs on its operation, you can check the filter’s condition every 30 days. Filters are meant to improve indoor air quality, yet they also act as a sign that something may be amiss.
Meade’s Heating and Air is Your Full-Service HVAC Company
When seeking an HVAC company you can trust for all kinds of issues, look to Meade’s Heating and Air. We provide complete heating and cooling repair, maintenance and installation. Our staff also handles boilers, heat pumps and ductless air conditioning. We have professionals experienced in gas line issues, water heaters, ductwork and air duct sealing. If you want to improve your indoor air quality, we can recommend and install whole-home air filtration, UV air sanitation, dehumidifiers and more. We can also set up a zoning system to make your home more energy efficient. Our company also provides coupon specials and access to financing for qualified customers.
With Meade’s Heating and Air, you don’t have to seek any other HVAC contractor in Virginia for your indoor comfort needs. Call our office today or schedule your service through our online appointment form.
