Furnaces, just like any other mechanical appliance, usually make some noise during operation. However, if your furnace is in good condition, this noise should be fairly unnoticeable. If your furnace starts making a strange and loud noise that you’ve never heard before, this could be a sign of an underlying problem that needs the attention of a professional HVAC technician.

The following are some of the furnace noises you should never ignore, what causes them and how they can be fixed.

Loud Humming Noise

Almost all furnaces in the market today produce a dull humming noise while they’re operating. However, if this humming noise becomes noticeably loud out of nowhere during a cycle, this could be an indication of an underlying problem with the blower fan or capacitor.

The best way to prevent further damage to your blower fan or capacitor is to contact professional HVAC repair services so that they can look into all the electric components of your furnace. This way, they’ll know what needs fixing and what needs replacing.

Banging Noise

A loud banging noise coming from the furnace is a very common concern among most homeowners. This problem is usually caused by a small gas explosion that happens when there is a delayed ignition. Therefore, if you hear a loud banging noise every time you turn on your furnace, it means that the appliance is not igniting right away like it’s supposed to.

Consequently, when the furnace doesn’t ignite right away, some gas will build up in its combustion chamber. After the furnace has fully ignited, all the built-up gas will cause a mini-explosion which can potentially damage your furnace. Delayed ignition is usually a result of low gas supply, dirty or misaligned burners, broken pilot light, as well as a mixture of too much air and gas.

Additionally, if you heat loud intermittent banging noises coming from your furnace, it could be an indication of expanding or contracting air ducts. A contraction or expansion of air ducts is usually caused by a dir air filter, closed/obstructed vents, as well as dirty or oversized ductwork.

If you hear such loud banging noise coming from your furnace, do not attempt fixing the gas burners on your own, as it can lead to a gas leak in your home. Instead, you need to contact a professional HVAC repair technician to come and inspect your furnace ignition system and make any necessary repairs.

High-Pitched Squealing or Whistling Noise

High-pitched squealing noises coming from your furnace are never a good sign and could be an indication of a problem with the blower. Remember, your furnace’s blower is usually powered by a motor that is fitted with bearings that can wear out due to age or overheating. Bearings on blower motors are supposed to last for about 30 years if proper HVAC maintenance is followed.

However, overheating can cause these bearings to expire prematurely and contribute to that high-pitched squealing noise your furnace is producing. Overheating is usually a result of dirt buildup or simply a bad capacitor.

On the other hand, if your furnace is producing a sharp whistling noise, this could be because of an airflow problem. When there is low airflow inside your furnace, it simply means that the blower is struggling to pull in enough air, which aids with heating. Some of the common causes of low airflow include a dirty air filter, obstructed vents, and dirty or damaged air ducts.

If you hear a loud squealing or whistling noise coming from your furnace, try changing the air filter and opening all the air vents to let in air. If this doesn’t fix the problem, it’s best to contact professional HVAC repair for further assistance.

Rattling or Rumbling Noise

A loud rattling or rumbling noise is a clear indication that something inside your furnace and it’s causing a vibration. This is usually a very serious problem because when there is a loose component inside your furnace, it can end up damaging other components of your electric or gas furnace.

Additionally, a rattling or rumbling noise from your furnace can be an indication of a malfunction in the furnace’s motor or also a leak in the heat exchanger. To fix such a problem, you need to contact a certified HVAC technician to inspect the blower motor, heat exchanger, gas burners, or the hot surface ignitor.

Do not attempt performing this inspection on your own, as it increases the risk of carbon monoxide poisoning in your home.

Are you looking for a reliable and reputable heating company to help with furnace repairs? Contact us today at AirDepot and let us take care of all your heating and cooling needs. We offer residential and commercial repair, installation, and maintenance services in the Cypress, TX, area.

company icon