If you maintain your furnace properly, you can expect it to last an average of about 16 to 20 years. To avoid premature wear and tear and other problems that could lead to more headaches in the future, keep an eye and an ear out for your furnace. Make sure that you take note of any signs of wear and perform the necessary repairs before the situation worsens and gets out of control. With that said, if your once-quiet furnace now rumbles and whistles whenever it's turned on, here are three fixes that just might work.

Clean the Filter

If your furnace has begun to make an unbearable whistling sound whenever it is turned on, there's a good chance that the whistling is caused by a dirty filter. The filter is responsible for making sure that air gets properly ventilated throughout the entire unit. Dirt and dust particles suspended in the air will start to accumulate on the filter's surface and will begin to clog it up. Even minor clogs can lead to an annoying whistling sound.

Depending on how dirty the filter is, you might be better off simply replacing the entire thing. This will not only make your job a lot easier but also be better for the fan motor. To make sure that the filter is the cause of the whistling, simply remove the filter before turning on the fan. If the filter is the cause of the whistling, the whistling should stop entirely.

Seal Gaps and Holes in the Duct

The tiny holes in the filter's meshes caused by the accumulation of dirt and dust particles are what cause the annoying whistling sounds that have been plaguing your household. With that said, small holes near the duct will have a similar effect as a clogged filter and will similarly make an annoying whistling or rumbling sound. If the filter isn't the cause of the whistling, you should check the duct next to determine if there are any holes or gaps present in the metal.

There are several ways that you can seal off the gaps, but the easiest temporary solution is to simply tape over the holes and gaps with duct tape. The annoying whistling sounds should stop immediately. Sealing up gaps and holes in the duct is also beneficial for the entire system, as this makes the system much more energy efficient. Heated air produced by the furnace cannot easily escape anymore.

Correcting Oil Canning in the Ducts

Over time, it's not unusual for metal components and parts of the furnace to become susceptible to oil canning. This basically means that the structural integrity of the metal becomes compromised, and it does not have as rigid of a structure as before. Generally speaking, you'll be able to easily identify which ducts or metal components are affected, as the noise will solely be coming from that part of the furnace. If some parts are struggling with oil canning, you can be sure that those parts have weakened and require additional support. If you don't repair this issue as soon as possible, the parts will only be under more and more strain. This leads to premature wear.

You can correct oil-canning by simply supporting the affected area with a thick piece of metal. This metal piece basically acts like a brace and will give the affected area its original rigidity back.


Don't sit quiet when your furnace gets loud. It's usually a sign that something needs to be repaired. If you don't determine what the problem is and repair the issue as soon as possible, your furnace's condition will only worsen with time. Minor problems will easily worsen and become large headaches and heartaches in the future.