Common Causes of Blocked Ducts in HVAC Systems

The weather in the central and eastern regions of North Carolina is fairly mild. While we get to experience all four seasons, we rarely see the extreme temperatures that other parts of the country do. If you live in North Carolina, you probably also know that temperatures can fluctuate pretty drastically from day to day.

Have you been noticing that the temperatures in different rooms of your house are not the same? Have your energy bills been higher than normal? While there are lots of reasons you may be experiencing uneven temperatures, one of the most common problems found in HVAC systems is obstructions in the ductwork.

If a duct is blocked, some rooms won’t heat or cool the way they’re supposed to. Because the rooms can’t reach the temperature you’ve set on your thermostat, your HVAC system will be working constantly to keep up. This is not only uncomfortable and expensive, but obstructions in your ductwork will lower air quality in your home. This can lead to certain health concerns, especially if you suffer from allergies or asthma.

In many cases, this is something you can fix on your own. To determine the cause of the problem, make sure your heat or A/C is on. Check each vent to see if air is flowing. If not, it could be blocked or obstructed in some other way. Here are some of the most common causes of ductwork obstructions.

Blocked Vents

Start by taking a look at the vents themselves. Are they covered by large pieces of furniture that could be preventing the air from flowing into the room? Are they dusty? If so, this could be the problem. Try rearranging furniture so that the vents are unobstructed.  Clean any vents that may have debris or dust on them.

Dirty Air Filters

Air filters should be changed regularly in order to maintain energy efficiency and good indoor air quality. If your air filters are dirty and clogged, they can impede airflow or cause your HVAC to circulate dirty air throughout your home. To determine how frequently you should change your air filters, check the manufacturer’s suggestion. It will vary depending on the type of air filter you buy, but every 30-60 days is typical.

Leaking or Damaged Ductwork

Use a flashlight to look as far down into your ducts as possible. Check for any loose seams or openings in the ductwork. It is not uncommon for ducts to become disconnected or damaged. Flex ducts are especially susceptible to these types of issues. In some cases you can fix these problems by replacing the old duct tape. In other cases, your ducts may need to be replaced.

Closed Zone Dampers

HVAC systems utilize dampers in the ductwork to control the way air flows in your home. You should be able to access and adjust them manually. Make sure all of the dampers in your home are completely open. Sometimes dampers can get stuck closed or can become loose and close on their own. This will completely obstruct the air in that particular duct and could affect the airflow in your entire house. If all of them are open and you’re still not feeling any air coming through, you may have another obstruction farther in the duct.

HVAC Damper Diagram

Physical Obstructions in the Ducts

Another common source of ductwork obstructions are physical objects inside your ducts. Dust, dirt, pieces of old air filters, and ductwork insulation that has come off are especially common culprits. You may also find debris from construction or remodeling projects, such as wood chips or insulation. Vermin or insects may find their way into your ducts and leave behind debris. Any of these physical obstructions can create problems for your HVAC system. If you see any and can reach them, remove them from your ducts immediately.

If you follow the advice above but are still having issues with proper airflow in your home, consider contacting Newcomb and Company. Our technicians are highly trained and dedicated to finding the most cost-effective and energy-efficient options to meet your needs. Schedule a service call today, because your comfort is our business!

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