Why Oil-Filled Electric Heaters Make Noises (Explained)

Is your oil-filled electric heater making a buzzing, crackling, or popping noise?

Many of us buy these types of heaters because they should be quieter than other options. However, it’s normal for oil-filled units to make some noise at certain times.

This article explains what kind of low sounds are to be expected and are no cause of worry. We also highlight the circumstances that indicate an appliance needs to be fixed or replaced.

Let’s start with the more worrying scenarios first and then continue with the normal kinds of sounds.

Noisy Signs That The Heater Has A Fault

When you hear buzzing or crackling sounds from the unit, try and identify if the noise is coming from either the

• plug or power cable, or
• timer or thermostat component, or
• main body (the fins)

If the noise is coming from the fins, then it’s more likely that this is part of the normal operation of the unit. This is even if the noise only started happening after the unit was over a year old.

We’ll explain in detail about “normal” sounds in the next sections.

If there is a buzz or crackle from the plug, power cable, timer, or thermostat component then this is likely an electrical fault.

You should unplug the appliance and not use it again until the problem is dealt with.

Why is the timer or thermostat crackling or buzzing?

Crackling from the timer or thermostat unit indicates an electrical issue.

For example, the thermostat contacts may have become worn in an older unit. If your unit is new, a manufacturing issue may have dirtied the contacts.

In either case, the contacts can arc as they come close. This electrical arcing produces a crackling sound. This is a problem that you will need to address.

Can a faulty thermostat be fixed?

Your parents would probably have nipped to a local electrical store to pick up a cheap replacement thermostat for their high-quality oil-filled heaters manufactured in local factories.

Many modern heaters are cheaper imports with components that aren’t designed to be swapped out and replaced.

DIY enthusiasts have described on YouTube how they used a soldering tool to remove a component from a circuit board and switched in a cheap replacement. That’s more trouble than I’m prepared to go through.

Calling out an electrician to fix the thermostat may cost more than buying a replacement heater.

If your appliance is still within warranty, you should simply get it replaced.

Why is the plug or power cable crackling or buzzing?

A buzzing noise from the plug or power cable is likely to be from loose wiring or a worn insulator.

You should stop using the appliance as it may be an electrical hazard.

Aside from unplugging it, you should put the appliance away until you’ve decided what to do with it. You don’t want someone else in the house to come along and innocently plug the faulty appliance back in again.

Replace, fix, recycle, or dump?

If the unit is new or still in warranty, you should get it replaced.

If an older unit is of high quality, then you may want to get it repaired by an electrician. However, the cost of repair may outweigh the purchase of a new heater.

Some people report that these electrical faults occur just a month or so outside the warranty period of a cheap model. Like many others, I can get rather suspicious about whether that kind of timing is a simple coincidence.

I’ve purchased many heaters over time and I don’t expect them to last more than a few years. However, if an appliance broke shortly after the warranty period, I would not buy that brand again.  

Regardless, sometimes your best option is to purchase a new heater and dispose of the old one. Check out our overview of how to recycle oil-filled electric heaters.

Why Do Oil-Filled Electric Heaters Make A Buzzing Or Humming Noise?

If this is your first oil-filled electric heater, then you may be relieved to learn that a quiet buzzing is not unusual. Here are some quotes I grabbed from people asking online about buzzes and hums.

This guy points out that he can only hear the sound when he’s standing next to the heater:

I purchased an oil-filled space heater and it’s making a buzzing noise. I hear the sound on the medium and high settings when I’m next to the unit.

This owner also reports a noise at the higher setting:

Our one will buzz slightly on 900 [watt].

So, you needn’t be alarmed. The same noise is reported with the cheapest brands to the most expensive.

Why Is The Heater Buzzing?

Most oil-filled heaters have several power settings, usually starting at 600 W and rising to 1500 W.

The 600W setting is probably completely silent. However, you may start hearing a faint noise at the higher levels.

If the heater is buzzing or humming at the higher power settings, then the likely reason is a minor vibration in the unit due to the current ebbing and flowing through the conductor.

There is nothing you can do to prevent this noise and the machine isn’t faulty.

But wait. Are you also hearing the buzz at the lowest level of power? There is one other possibility that is nothing to worry about – but you should fix it.

There may be a screw slightly loose in the frame of the unit. Examine the wheels and brackets that you probably attached to the main body after you purchased the unit.

Why Does A Heater Make A Clicking Or Ticking Sound?

If your heater is making clicking and ticking noises when it heats up, this is simply due to the metal parts expanding slightly as the unit heats up.

As the parts move slightly and tap against each other, they make these clicking and ticking noises.

This is the same reason why you may hear clicks when you’ve turned off the heater and it is cooling down. Again, the shifts in the metal parts cause the noise.

This is part of the normal functioning of an oil-filled heater.

However, if the ticking noise persists or only starts when the unit is fully heated, then you should pay more attention to where the noise is coming from.

If the noise is coming from the thermostat or timer unit, then read the second section in this article.

Older Heaters May Start Making Louder Clicking Noises

Some owners of quality heaters get alarmed because loud clicking noises only start to happen when the unit gets older.

If you think this noise is coming from the timer or thermostat, then jump to this section.

However, if the ticking only happens when the unit is heating up, then this is likely due to a slight change in the nature of the oil.

Oil simply gets a little thicker as it gets older. When you turn on the unit, the oil expands a little more as it is heating.

The metal components move and shift a little more than they used to. So, now you hear the clicking noises in these older units.  

Why Does An Oil-Filled Electric Heater Make Crackling Or Popping Noises?

Is it normal to hear your oil-filled heater making snap, crackle, and pop noises?

Well, you may be eating a popular bowl of cereal and are confused by the source of the noise!

Only joking. Let’s take a look at when there is no cause to worry and when you may need to investigate.

It’s normal for oil-filled heaters to make popping sounds when the unit has been turned on and is rapidly heating up.

If there are tiny air bubbles in the oil, they will rise toward the top of the unit and burst. This can produce an audible popping noise.

Is There A Dripping Noise Coming From The Fins?

There are some circumstances when you’ll hear what sounds like liquid dripping inside your heater. This can be a little alarming, but there’s usually no reason to worry.

The dripping noise usually starts when you stand a heater upright after it has been on its side.

The reason is that the fins aren’t completely full of oil. This means that you can hear oil that had gathered at the inner top of the fins dropping back down as it is now upright.