hvac troubleshooting

HVAC Troubleshooting: The 10 Main Causes of Airflow Issues in HVAC Systems

HVAC Troubleshooting: The 10 Main Causes of Airflow Issues in HVAC Systems

The average homeowner spends more than $1,200 on electricity each year. And a good portion of that cost is due to their air conditioner during the summer months. It’s normal to see a spike in energy costs when the temperatures start to rise. But if you feel that the system’s airflow is weak, you might end up running the system longer, spending more money on electricity month after month.

With a little HVAC troubleshooting, you should be able to identify the cause and fix your AC quickly, reducing your electric bills immediately.

Here are a few of the most common causes of weak airflow to watch for.

1. Blocked Air Vents Inside the House

Air from your air conditioner flows through the ductwork and out the vents throughout your house. When there are clogs in the vents or they’re covered up, the cold air can’t reach your room.

This means you’ll be sitting in hotter temperatures than you should, no matter how low you turn the thermostat.

When starting your HVAC troubleshooting process, walk around your house and inspect each air vent. If they’re covered by furniture or closed, open them up and clear the area a few feet away from the vent.

This will give you access to better airflow immediately and helps your system cool your home more quickly and efficiently.

If the vents look damaged or you can’t open them to allow for airflow, you may need to replace them with new covers. Measure the opening, buy the appropriate covers, and install them yourself.

dirty air filter

2. Dirty and Clogged Filters

Your air conditioner draws fresh air from outside the house, brings it to the ideal temperature, and sends it to the different rooms of your home. While it’s effective and keeps the air inside from getting stale, it also introduces contaminants into your home.

Things like dust, dirt, allergens, mold spores and other contaminants get sucked in along with the fresh air. That’s why every modern system has durable filters that catch those unwanted contaminants.

Though they can last for a while, they will eventually need to get replaced. When the filters trap contaminants, the amount of air that can pass through the filter gradually decreases. Once the filters are full or clogged, you’ll feel a noticeably weakened breeze from your AC.

Check the filters at least once every month and replace them as soon as you see that they’re dirty. For most homeowners, the filters need to get replaced once every three months. But the more you use the system, the more often you’ll need to install new filters.

3. Bent Condenser Fins On Exterior Unit

Standard central air conditioning systems have outdoor condenser units. These units get exposed to the weather and elements every day. Even if you cover them, it’s not always enough to protect the system from damage.

And the most easily damaged component is the condenser fins. These look like wavy tubes and wires on the outside of the unit.

Air passes through those tubes and into your home to get cooled and distributed. But when the fins get bent or damaged, it can decrease airflow and leave you with an underperforming HVAC system.

Luckily, you can repair the fins. Just use a dull butter knife and gently bend the tubes back into alignment. If you’re not comfortable doing it on your own, schedule an appointment with your air conditioning repair technician and let them fix the problem.

4. Damaged Ductwork

Unless you’re using a window air conditioner or a ductless system, your conditioned air flows through ductwork in your walls and ceiling. Think of the ductwork as pipes for your HVAC system.

When they’re in good shape, the air flows from the air conditioner out into your house without issue. But if they’re bent, dented, or punctured, you could start leaking air.

This often results in low airflow out the vents in your home. The only way to fix damaged ductwork correctly is to schedule an appointment with your repair expert.

But you can look for signs of damage on your own. In the attic, basement, or any room where ductwork is visible, look for holes, dents, and rust on the surface. If you find anything that looks questionable, get it fixed as soon as you can.

5. Old Blower Fans

Both your furnace and your air conditioner rely on their blower fans to power air through the ductwork. When they’re in good condition, the system sends air at the ideal flow rate throughout the ducts and into your house.

But if the fans are old, damaged, or have dying components, you may notice decreased airflow.

Your HVAC technician can tell you if the problem is due to a failing fan motor or if the airflow has slowed due to a buildup of dust and debris on the fan blades. Regardless of the cause, it’s relatively easy to fix and once you have new fans installed, your system should work properly.

old air conditioning unit

6. Poorly Sized Unit

When air conditioners get installed on a house, they’re supposed to get measured and sized properly. Different systems work best for different square footages. Larger homes require larger units.

When your residential HVAC system is too small, it has a seemingly weak airflow. This is because the components can’t keep up with your home’s cooling needs.

This is largely a problem in homes with older units, but some contractors inadvertently install the wrong size system when building houses. The only way to fix this is to replace the unit with an air conditioner that can handle your cooling demands.

There’s no simple way to force a smaller system to have stronger output if your house is too large for it.

Too Big Can Be Just as Bad

Before you think to install the largest unit you can find, know that it can be just as dysfunctional as a unit that’s too small.

Oversize systems rapidly cool certain areas of your home. But they also introduce major humidity issues in your house. Worse, they won’t cut on as frequently.

This means the airflow you feel will be short-lived at best.

7. Debris Buildup on Condenser

Dust and debris get everywhere within even the best-maintained HVAC systems. It’s a side effect of bringing fresh air in from outside the home.

But that buildup can weaken your air flow when it collects on the condenser unit.

The condenser is the main cooling component of your air conditioner. When it’s covered in dust and dirt, that debris can clog the moving parts. When this happens, the fans and belts move more slowly, reducing the airflow and leaving your home warmer than it should be.

Routine maintenance appointments and cleaning sessions will help get rid of the buildup and restore your system to full power.

a/c repair man filling up unit

8. Leaking or Low Refrigerant Levels

All air conditioning systems use refrigerant to cool the air. When the system has enough refrigerant, it maintains proper pressure levels throughout the process. This results in better airflow throughout your home.

But when you have a refrigerant leak or low refrigerant levels, the airflow suffers. You’ll find it harder to keep rooms cool. And, worse, you might notice that the air coming out of your vents is warm.

It’s rare that the problem is due to depleting refrigerant levels—instead, it’s almost always the result of an active leak. The only way to fix the problem is to repair the leak completely and top off the reservoirs. Your HVAC repair expert can do this for you.

9. Damaged Thermostat

The most overlooked cause of many HVAC woes is the thermostat, not the system itself. Thermostats are notorious for breaking or shorting out without you realizing there’s a problem.

If the thermometer breaks, the system may not cut on when it needs to, making it feel like you have lower airflow. And if the variable fan setting gets changed without you knowing it, the airflow will seem lower than it should.

The best thing you can do is to check your thermostat. If the settings have changed, change them back. But if it seems like your thermostat is going bad, it’s best to replace it.

10. Old and Outdated AC System

Unfortunately, central air conditioning units don’t last forever. In fact, most only last about 15 years before they start showing their age.

When this happens, airflow issues are normal. The components are older and lack the mechanical strength to produce the airflow you need.

The best thing you can do is upgrade your unit. Though the average AC system costs between $3,000 and $7,000, it’s well worth the investment.

Newer systems are more energy-efficient and will cool your home at a fraction of the cost you’re used to paying. Keep in mind that it’s best to speak with your HVAC technician before you make a decision. They may be able to extend the life of your current unit for a few years, helping you save money for the newer upgrade.

Final Thoughts on HVAC Troubleshooting for Airflow Issues

If you’re worried about airflow issues, this HVAC troubleshooting guide is a great place to start. But it’s always best to consult with your repair expert and make sure you find the root cause of the problem.

Contact us today to schedule a service appointment and let our pros keep your system running well no matter how hot it gets outside.

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