Tuckers Air Conditioning, Heating & Plumbing Blog

Furnace Buzzing? Here’s What That Sound Means


Your furnace makes fairly few noises, like the rush of air when it kicks on, or some banging when you hear the ductwork expanding.

But there’s one sound it should never make: buzzing. This is a sign of electrical problems with your furnace, and it’s serious. It’s enough of a cause for concern that calling for heater repair in Frederick, MD is the next step. Let’s talk about all the reasons that your furnace might buzz and get into the specifics.

Inducer Motor Went Bad

Your HVAC system has a fan that’s powered by a motor and an electrical box—that’s basically what an inducer motor is. There’s an electrical connection that helps power it and control the speed, and this is what helps push air through the ductwork and into the rooms of your home.

It’s not so easy to tell if that’s where the buzzing is coming from without a proper diagnosis, but there is one way that you can find out. If the electrical connection is bad, it may damage or destroy a sensor that helps control the fan speed.

When your furnace is turned on, it should blow out warm air. But if you put your hand up to your vents and it’s only mildly warm or kind of cool air, it means the fan is spinning so fast, it’s actually cooling the warm air before it makes it to the end of the ductwork.

Transformer Is Going Out

The transformer controls the electrical output in your furnace. In short, it prevents the electrical components of your furnace from receiving too much electricity all at once.

This is important because different wires and components are rated for different amounts of electricity. If you overload one, it can lead to damage, a complete breakdown, or a fire.

Think of your transformer as a stern safety inspector for the flow of electricity inside of your furnace. If it’s on its way out, you have to replace it as soon as possible.

Blower Motor Capacitor Is Dying

We know transformers control the flow of electricity, but some of that electricity makes it to a capacitor. This basically holds a small amount of charge within your blower motor that can be released rapidly and as-needed. It’s there because it’s required for your blower motor to operate effectively. With a dead capacitor, your blower motor may not run at all, which means no warm air comes out of your furnace.

If you have a buzzing sound, and you’re not experiencing any air flow at all when you turn your furnace on, it’s likely the capacitor.

Fix That Furnace Buzz

Buzzing is an indicator of electrical problems, and those are the precursors to electrical fires and major damage to your unit. It’s not something you want to mess around with.

Don’t wait, don’t delay any longer: you need to schedule repairs before you continue to use your furnace in any capacity. Let a professional technician assess the situation and see what’s going on with your furnace.

Contact Tuckers Air Conditioning, Heating & Plumbing today to schedule furnace repair as soon as possible.