Clean Air, Home Improvement, HVAC

What A Dirty Air Filter Says About Your New Home


The one thing you never see on shows about house hunting is the perspective buyer asking to check for a dirty air filter. Absolutely check the foundation and roof, but if you want to know how the well the previous owner or tenant maintained the home or if there are any underlying issues with the construction, a lot will be revealed by looking at the heating and cooling system.

A Dirty Air Filter Could Be A Sign Of Things To Come

The air filter in the heating and cooling system not only helps to clean the air in the home, but also helps to reduce the amount of dirt and debris, bugs, and other contaminants from reaching the blower, the coils, and all of the duct work that is routed through the home.

When inspecting the air filter, do you only see gray dust, or is there discoloration, bugs, or a weird smell that may indicate one or more problems? If you find anything out of the ordinary, you could be facing potential problems with the home now or in the future.

Leaks In Ducts Or Exterior Walls

Allowing fresher outdoor air to come inside a good thing, but only when it is controlled by a specially designed vent. In the case of a leak in the structure of the building, dirt, rain, bugs or animals could come into the home. This leak could be on the exterior of the building, but it could also be found in the ducting, which is allowing insulation or other particles to get blown into the interior of the home.

Hidden Mold Problems

Once mold gets into the home, it can stay in the home for as long as it stands. Mold reproduces by releasing spores into the air. Only once they find a habitable area with moisture and nutrients will it begin to grow, then release its own spores, and continue the cycle. While you might not find mold growing on the filter, you will still notice the distinct odor produced by mold. If you do notice an unpleasant smell, mold could be somewhere you can’t see without a more thorough inspection.

Inefficient Heating and Cooling

If the air flow through the heating and cooling system is slow, replacing the air filter will most likely help solve the issue. However, if the coils are dirty or the ducts are full of dirt, you could be dealing with a more serious problem. The coils are a piece of metal that heats or cools the air being pushed through the system by the blower. Dirt and debris on the coils will behave similar to insulation and prevent the air from warming or chilling.

Unexpected Heating And Cooling Repair Costs

Everything we have listed will cost time and money to fix. Especially if the excess strain that has been put on the heating and cooling system results in equipment failure. The cost of repair can exceed $10,000 depending on the size of the unit. If mold has spread through the foundation or the drywall, it will need ripped out and replaced.

No Filter Or New Filter

If there is no air filter, then you will need to ask the realtor or property manager if one has ever been used. If the air filter looks new, don’t walk away without removing it and inspecting behind the filter to see if the are signs of neglect.

Check The Other Filters Around The Home

The heating and cooling system isn’t the only place to look for a dirty air filter. There are some filters located throughout the home that you can also check to discover a little more about the people who lived in the space before you.

  • Refrigerator Air Filter
  • Range Hood Filter
  • Dryer Filter
  • Window Screens
  • Aeration Filters

Read our blog about the 6 filters you need to change after moving!

Not all homes have these filters, but knowing where they are and replacing them will help give you a fresh start in the home and making sure vents and faucets and other equipment run at their best.


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