Why Is My Furnace Making a Humming or Buzzing Noise?

furnace noise buzzing hummingLet’s say you’re simply relaxing at your home in Aurora, Oswego, Plainfield, Naperville or Lisle (IL). Maybe you’re making dinner, watching TV or reading the paper. It’s a bit cool outside, so the furnace starts up to maintain your temperature setting.

Suddenly, you notice the furnace is making a strange humming or buzzing noise. You haven’t heard it that way before. What could it be?

As a machine with moving parts, your furnace will make some normal sounds during operation. If it makes an obvious humming or a buzzing noise, it could be a sign that the unit needs basic maintenance, or it could indicate something is failing. We’ll talk about that further here, because it’s something to be aware of and knowledgeable about.

Furnace Is Making a Humming or Buzzing Noise: Blower Motor

The blower motor is vital: It is what moves heated air from the furnace into your home. It is also one of the most common sources of a humming sound in your heating system.

A humming or buzzing noise could indicate a bad blower, and if that part is failing, you’ll soon be without warmed air. The furnace also will still be drawing energy to operate even though it isn’t producing heat.

If you suspect that a humming or buzzing noise could be a bad blower, the first thing you should do is turn off the motor and allow it to cool. Also contact us at Beery Heating and Cooling so we can advise you on the best way to proceed. An inspection can determine whether the blower motor simply needs lubrication, there is an amperage problem or a motor failure could be near.

Because the blower is such a common reason for a humming or buzzing noise, here are some other things to consider about a strange sound as it applies to the blower:

Humming at slow speeds. Once your house has been warmed to your set temperature, the blower will start to run at a slower speed. This is a normal, built-in way the motor saves energy. However, if your blower motor seems to be slowing down oddly while also making a humming sound, it might be a failure in the motor and the capacitor (more on that in a moment).

Note also that a frequent culprit of a straining or failing blower motor is simply a dirty air filter. A clogged, thickening filter makes the motor work harder in moving air, which can lead to a premature breakdown. Always be sure to check the filter on a regular schedule.

Humming when the blower is off. If you hear humming when the motor isn’t running, it could be because the pilot light is incorrectly adjusted. Readjusting it to a proper level should fix the issue. If adjusting the pilot light isn’t something you’re comfortable doing on your own, just give your professionals at Beery a call.

Humming when the blower is off. Dirty gas burners will emit a low sound that might resemble something between a low rumble and a hum. The heating professionals at Beery can clean, adjust or replace them to make the sound disappear.

Furnace Is Making a Humming or Buzzing Noise: Other Causes

The following are a few scenarios that could be behind a humming or buzzing sound from your furnace in Aurora, Oswego, Plainfield, Naperville or Lisle.

Loose equipment. In older or infrequently maintained furnaces, components such as belts, nuts and bolts can loosen. This is why annual inspection and maintenance is so important – if loose parts aren’t identified and fixed or adjusted, the furnace can fail, leading to much bigger problems.

Loose ductwork. The average length of home ownership is around 16 years. During that time, the joints and seams in the home’s ventilation ductwork can become loose. The ducts are made from thin sheets of metal, and they become more pliable as they age and wear. This can cause the seams to vibrate and hum. Ducts should be inspected periodically to ensure they are properly sealed and secured.

Transformer. Although the least likely cause of humming or buzzing, a failing transformer might make noise as electrical current moves through it. If that’s the case, the transformer will probably need to be replaced soon – certainly before it fails and the furnace stops functioning.

Capacitor. If the blower is on and humming but the motor isn’t turning, the capacitor may be damaged or close to failure. This tends to be a common issue with blower motors that do not have better-quality capacitors in them. The part should be repaired or replaced promptly so the capacitor functions correctly.

Here for Answers and Service

Beery Heating and Cooling specializes in furnace installation, repair and maintenance for homes in Aurora, Oswego, Plainfield, Naperville and Lisle. If you ever have questions or concerns about a humming or buzzing noise from your furnace, we’ll be ready to hear from you and assist you. Just give us a call at (630) 585-6444!

We are available for furnace installation, repair and maintenance throughout the area, including Plano, Batavia, North Aurora, Yorkville, Montgomery and Sugar Grove.