Why is My Air Filter Black?

If you recently changed your furnace air filters and noticed that they were black, don't worry. In most cases, a black air filter is usually from soot and can be a result of:

  • Candles
  • A gas fireplace
  • Gas appliances

While soot isn't "dangerous," it' still not something you want around your home and in your air.

Below, we'll look at each of these potential soot-causing culprits in more detail, so you can get a better idea of what's causing soot and how to prevent it.

Factors that Cause Black Air Filters

Reason #1: Candles

During this time of year, it's popular to burn scented candles throughout your home. However, many types of scented candles are made with oil that doesn't "burn clean."

This means that some types of scented candles release soot into the air, which can gather on your walls, fabric surfaces and on your air filter.

A good indication that your candle is producing soot is the color of its flame. If the candle's flame is yellow or orange, it's probably producing soot. If your candle burns blue, it's probably burning clean.

If you want a candle that doesn't produce soot, look for one that doesn't have petroleum jelly or vegetable oil in the ingredients. You can also reduce soot by keeping candle wicks trimmed below ¼ of an inch.

Reason #2: Gas Fireplace

Gas fireplaces are actually made to produce a yellow/orange colored flame, which, as you now know, produces soot.

Unfortunately, there isn't a lot you can do to prevent your gas fireplace from producing soot, but there are a few ways to reduce the amount of soot that finds its way into your home's air.

A few ways to reduce the amount of soot that a gas fireplace produces includes:

  • Having a professional check the burner of the fireplace every year
  • Removing old or damaged logs
  • Keeping the fireplace doors open if your gas is turned on

Another tip would be to replace your air filter regularly during the months of the year in which you turn your gas fireplace on often. This will keep the air circulating around your home as clean and soot-free as possible.

Reason #3: Gas Furnace or Water Heater

If you have a gas appliance, like a gas furnace or water heater, there is a chance it could be producing soot.

Soot happens when your gas appliance isn't burning gas properly or the ratio of gas to air is off.

If you have a gas furnace, the soot could be coming from the heat exchanger or improper venting. If you have a gas water heater, soot could be coming from a clogged gas valve or clogged burners.

If you think soot is coming from a gas appliance, our advice would be to reach out to an HVAC pro that specializes in gas appliances to take a look at your system. NOTE: At Advanced Air, we do not repair gas water heaters or gas furnaces.

Alternate Reason: Your Black Air Filter isn't Covered in Soot, it's Just Really Clogged

Outside of soot buildup, your air filter might appear "black" if it's just extremely bogged down by particles that have gathered on your filter. On average, we recommend that homeowners replace their air filter every 1-3 months to keep your home's air clean.

If you have a black AC filter, but you don't have gas appliances and don't regularly burn candles, your air filter may just be really dirty.

At Advanced Filters, we offer a variety of air conditioner filters for sale online, so if you're running low or realize you need to replace your air filter, you can easily purchase one and have it shipped to your house.

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