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Identifying Furnace Airflow Reductions

Airflow is one of the most important functions of an HVAC system, because equipment life, utility costs and comfort are all impacted by the system airflow rate. When your furnace's airflow is reduced, the temperature in your home may be uneven and air distribution in your home will be subpar at best. If this is the case, you'll need to have your system inspected by a professional to figure out what's going on.

Why do furnace airflow reductions occur?

A furnace's airflow rate can reduce for a couple of reasons. Most often, it reduces because the system's air filter is clogged or filled with dirt, or because there are gaps or cracks in the system's ductwork.

How to check for a clogged air filter or cracks in the ductwork

  • Find the filter in your furnace. Filters will always be on the return side (where the air flows into the furnace). Typically, they are just beside, above, or below the furnace itself. In some cases, you may need to remove an access panel to see it. If you do need to remove a panel, ensure the furnace is turned off beforehand.

    Once you've found it, check to see if the filter looks grey. If there's dirt and dust buildup on the filter, it's time to change it.

    CAUTION: Be sure to turn the power off to any piece of HVAC equipment before removing access panels to avoid injury from rotating parts.

  • Go throughout your home and check on the vents in each room. Are the registers in those vents open all the way? If not, open them to see if the issue improves. Furniture placed over or near a register will also affect air circulation. Keep that in mind when arranging furniture in a room.

  • It is difficult to know if there are leaks in your duct, but there are a few ways to tell. Inspect your air returns and vents to see if you see any cracks or gaps in the ductwork feeding them. If there are visible cracks or gaps, air is escaping from your ducts, which will cause poor airflow and distribution.

  • It can sometimes happen that your ductwork is too big (wide) or too small (narrow) to handle the airflow requirement of your heating and cooling system and your home. Have your system inspected by an HVAC professional to find out if you are using under or oversized ductwork.

If these steps didn't point you in the right direction, consider other sources of whistling from the ducts.

What To Do If Your Furnace's Airflow is Poor?

The solution to restoring proper airflow in your home's system depends on the issue's source. If your filter is indeed clogged, you'll need to replace it, and your airflow should return to normal levels.

If changing the filter doesn't restore airflow patterns, you've probably got cracks in your ductwork, a broken air handler, or something more complicated that will require a technician's expertise. You can reach out to our Remote Assist expert for a virtual diagnosis.

NOTE: This content is for informational purposes only, and HomeX and its affiliates disclaim all liability related to it. If you decide to perform any tasks based on this information, you assume all risks, including the risk of loss or damage to property or personal injury.

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