Reasons You Need to Call Your Heating and AC Service Provider | Lewisville, TX

Reasons You Need to Call Your Heating and AC Service Provider | Lewisville, TX

Photo By Champion studio at Shutterstock

Some people say that when their vehicle starts making a suspicious noise, they just turn the radio up a little louder and keep going. Similarly, a lot of people hear noises coming from their HVAC system and walk away hoping for the best. Since most heating and AC systems are in the basement it is easy enough to ignore sounds that are out of the ordinary. However, in this scenario, ignorance is not bliss, because ignoring unusual sounds may result in much more costly repairs.

No one wants to pay for HVAC repair in Lewisville, TX, but no one wants to wake up to find that their entire system has quit working. whether that means sweating out a hot day or freezing on a cold day, it is best to troubleshoot any odd sound you hear coming from your heating and AC system pronto.

Amazingly enough, different sounds actually serve as diagnostic hints to Lewisville, TX technicians when they are investigating what is wrong. The sounds you hear are actually indicators of problems with your HVAC system. The following is a quick guide to common HVAC system sounds and what they mean. However, remember this is just a guide, you should always seek out help from a trained heating and AC technician to properly check and repair your system.


A gentle humming noise from your heating and AC system is actually okay. Many systems hum when they are working, and there is nothing to be alarmed about unless the humming has a different pitch or intensity than usual. Over time the humming becomes white noise in most homes, so if something is suddenly significant enough to notice, its significant enough to call an HVAC technician in Lewisville, TX about.


One of the most common complaints that HVAC technicians hear revolves around knocking. Many people report that their heating and AC unit seems to be making a knocking noises. Generally, when you hear knocking it means that the vibration damper is not in its correct position which is making the sounds of the blower echo through the system. It’s not a bad idea to have this checked, but all things considered, it’s not the worst sound to hear.


If you hear a rattling noise that sounds like someone dropped a few coins down the heating duct, it is likely loose metal pipes that are now knocking against each other. This is more likely to occur in an older HVAC system than a newer one. As the heating and AC ages, the sealant loses its overall effectiveness. Combined with static pressure, the ducts can slowly start to work their way loose.

On the other hand, vibrating ducts can also be the result of a clogged filter. The filter blocks airflow from passing through which leads to a pressure drop. The end result is the ducts start to shake. Be warned though, if the noise sounds more like a buzzing or scratching than vibration you may have a squirrel, mice, bees, or raccoon in your ductwork. In this scenario, you may find help from a pest control more helpful than an HVAC expert.


Not to be confused with banging, a banging noise sounds exactly like you would expect. Imagine someone standing next to the unit or the ductwork loud banging on the surface with their palm. Banging almost always indicates that there is a broken or loose part in your heating and AC system. Usual culprits include the connecting rod, crankshaft, or piston pin.

Sometimes banging can also indicate that the indoor blower has gotten out of balance. Other times, it may be a sign that it is time to replace the compressor on your heating and AC unit. Due to the potential for these issues to completely shut down your HVAC unit, banging is something that should always be addressed in a timely fashion.

Squealing or Grinding 

In most cases, squealing can be attributed more to your furnace than your AC, but there are always exceptions. Most of the time squealing noises originate at the blower or the heat pump and indicate that a belt has frayed or the blower housing needs to be cleaned.

Of the two, squealing is a much better sound to hear. Grinding on the other hand could mean that the blower motor is failing or is about to die completely. It is better to take care of the noise while it is still just squealing, then wait and have the sound escalate to grinding when it is probably too late to do anything but fully replace the blower motor.


Much like real life, you never want to hear screaming from your HVAC system. If the sound is simply voluminous and screechy, you need to immediately turn off the heating and air unit and call up a Lewisville, TX HVAC professional. High pitched screaming like noises can indicate many health hazards that are not worth taking any chances with. Some of the most common causes of screaming noises from the AC include high internal pressure inside the unit which could escalate into an explosion or a refrigerant link which is a serious health hazard.

Noises from your HVAC system are always a warning that something is malfunctioning within your unit. As you have seen, the problems can range from mild to potentially life threatening. Unless you are a certified HVAC technician, it is always a good idea to call a heating and AC system expert if you hear noises that are not normal for your system. You will not only save money by being proactive, but you will help keep your system in top shape which in turn will extend its overall lifespan.

Call K&S Heating and Air for all of your heating and air conditioning needs!