Why is my air conditioner making a humming noise?

If your air conditioner is humming, it might mean there is an electrical or mechanical problem. Take steps now to identify the issue with your air conditioner.

Potential causes of your cooling system’s humming can include:

• The condenser fan motor on the unit might be unable to spin but is still connected to power, creating resistance that produces a pronounced—and often loud—humming sound.
• There could be a mechanical or electrical [malfunction|failure|breakdown]9] with the contractor relay switch, the component responsible for starting the outside unit when the indoor temperature rises to the level where cooling is necessary. When the contractor breaks, it can create a humming sound. The switch should be in the exterior condenser unit outside your home.
• The circuit breaker is overloaded - normally, your circuit breaker trips when it becomes overloaded. However, if the circuit breaker is faulty and cannot trip, you might hear an electrical humming noise.
• Ice on condenser - if your unit freezes up, this can result in a loud humming or buzzing noise. If your air conditioner is frozen, there are a few other potential causes such as a refrigerant leak, clogged air filter or broken blower motor. A broken blower motor will sometimes create a humming or buzzing noise, and is located in your furnace. If the furnace is located close to the exterior condenser, you might mistake the source of the humming noise. With the AC running, found out if the humming or buzzing is louder near the exterior condenser unit or the furnace.
• The AC Condenser Fan Motor is broken - similar to the blower motor failing, a broken condenser fan motor can also make a humming noise when it fails. If the indoor blower is working but the fan is not turning, your fan motor may emit a loud buzz. Some people perceive this noise as more of a hum than a buzz. There can be different causes for a failure of this component including debris reaching the condenser, overgrowth surrounding the unit, loose parts, etc.
• Loose components inside the air conditioner - Your HVAC system is a complex machine with a large number of moving parts. Over time, it’s possible that some parts shook loose due to normal wear and tear. A loose part may cause premature wear and loud noises, including a humming noise.
• Refrigerant pipes are vibrating - If the refrigerant lines are undercharged, it can cause vibration. This vibration will sometimes sound like a humming noise. There may be other causes for a vibrating refrigerant line, such as an improperly mounted expansion valve.

A humming sound is evidence that something inside your air conditioner is off and needs attention. Given the causes above, it’s crucial to determine where the sound is coming from. Your entire HVAC system is interconnected. The air conditioner needs adequate airflow to operate normally. Air passes through the air filter, and it’s the blower motor (located inside the furnace) that circulates air through the entire system to heat or cool your home. If the air filter is dirty, or the blower motor malfunctions, that can cause issues with your condenser unit located outside the home.

Resolving the AC humming issue requires a technician to perform a diagnostic assessment on your whole unit. This work should never be completed by a homeowner, but only by a trained technician. Your HVAC system has hazardous refrigerants running through it that should be safely handled only by a professional. Electrical components to your system should never be adjusted by a novice due to the risk of electrocution. Homeowners are better served trusting an HVAC company to examine and repair their system if they notice any odd humming, whirring, or buzzing noises coming from their unit.

If a component like the blower motor is damaged, it may be because your furnace is near the end of its lifespan. The blower motor is not a component that needs to be replaced on a regular basis. Working with Winnipeg Supply Service Experts, we will not only diagnose your problem and provide recommendations to resolve things as soon as possible, we’ll also assess your HVAC system entirely. If your unit has to be replaced, we have affordable options with top tier service available through financing. We also have the Advantage program that will get you a new system for a low monthly rate.