If you’ve ever experienced an electrical humming noise somewhere in your home, you know how maddening it can be. Sometimes it’s so difficult to track this kind of noise back to its source that you might start thinking your ears are playing tricks on you. But these hums and buzzes are fairly common, and we know a few tricks that will help you pin them down. The sounds might even be warning signs of wiring problems, so the investigation is worth the effort.

On the Hunt

When you just can’t figure out where the hum is coming from, there are four simple strategies that may lead you to the source.

  • Make an ear trumpet. Before modern hearing aids, ear trumpets were the go-to tools for the hearing impaired. An ear trumpet is simply a small, hollow horn that makes nearby sounds easier to hear when the small end is placed over your ear. You can improvise with a funnel, a traffic cone, an old megaphone or even a rolled-up piece of paper. Walk around your home with your ear trumpet engaged and see if that leads you to the source of the hum.
  • Use a stethoscope. This is especially handy if you suspect the hum might be coming from an outlet, a fixture or the wiring within your walls. Some drugstores sell cheap versions that will work well enough for listening through the surfaces in your home.
  • Use a microphone and headphones. If you happen to have decent quality recording equipment, a good condenser microphone may help you zero in on the noise. Set one up to feed directly into some powerful headphones for some higher-tech investigation.
  • Use the process of elimination. Shut off all the circuit breakers in your home. If you still hear the noise, you know it’s not coming from your electrical system or plugged-in appliances. If you can’t hear it, turn the breakers back on one at a time until the noise returns, then check every appliance, outlet, light switch and fixture on that circuit.

What Does It All Mean?

Some noises are harmless, if irritating. Others can be the byproducts of bad wiring or electrical failure, and some of those causes can be very dangerous. If you’re ever in doubt about whether the source of the noise is a safety concern, shut down the device or circuit making the hum and call an electrician for a safety inspection.

Here are some common sources of electrical humming, along with their likely causes:

  • Light bulbs and fixtures. Many fluorescent light fixtures make a humming sound, and you may need to switch to a different fixture type to get rid of it. Sometimes the sound can come from the bulb itself, especially if it’s a cheaper bulb or if it’s being used on a dimmer. Upgrade to a high-quality LED bulb to see if that quiets things down.
  • Electric or gas meters. Newer digital meters are almost always silent, but older meters that have moving parts may emit a noise you can hear inside your home. If you find this is the case, contact your utility provider to inquire about meter replacement or planned upgrades.
  • “Mains hum”. This is something of a catch-all term to refer to the audible sound of alternating current. You may hear this sound coming from appliances that contain electric motors, such as dryers and refrigerators, or from electrical transformers outside your home. Unless the hum becomes a loud buzzing sound, the mains hum is normal and harmless.
  • Wiring and outlets. These elements can hum for a variety of reasons, many of which signify danger. If an outlet is not grounded properly or if wiring is transferring voltage above the level for which it’s rated, they may make a humming noise and could eventually spark a fire. Call an electrician to investigate these sounds.
  • Circuit breakers. These are designed to trip when there’s too much voltage coursing through a circuit, but some defects or malfunctions can prevent this from happening. This can keep the circuit in an overloaded state, which will produce noise from the breaker box. This should be addressed by an electrician as soon as possible.

If you have an electrical humbugging you in your home, take a few minutes to try to track it down. If you need help, or if you trace the sound back to something troubling, reach out to your local Mister Sparky and ask for assistance.

Finding and Fixing a Low-Frequency Electrical Hum