Furnace Noises: What Causes Them & How to Deal With Them

Furnace Noises: What Causes Them & How to Deal With Them

A home furnace isn’t exactly the most silent piece of equipment out there, which is why it can be hard to determine if the sounds coming from it are normal or an indication of a problem. Knowing how to distinguish a small issue from one that requires the urgent attention of an HVAC technician can also be difficult.

The Meaning Behind Strange Furnace Noises

The following are some of the unusual noises that a furnace may make and the meaning behind them:

• Banging Noises

A continuous banging or popping noise inside the furnace could signal one of a number of problems. For instance, the heating unit has likely accumulated too much dirt. If not removed immediately during a routine maintenance check, gas combustion issues may ensue, resulting in various problems like cracks and splinters on the heat exchanger or an ignition delay. It’s also possible that the ductwork is experiencing expansion and contraction during cold weather. The sheet metal contracts at low temperatures and expands when the furnace turns on. Stress at the duct seams then occurs, causing the metal to buckle outward and produce a banging noise.

• Scraping Noises

A loud scraping noise inside your furnace could mean the blower wheel has moved out of alignment and is hitting the blower house casing repeatedly. The grinding sound of metal against metal should be enough of a signal for you to turn the heating equipment off and call a technician to have the issue fixed.

• Rattling Noises

You shouldn’t worry too much about this kind of noise coming from your furnace. The problems associated with it, fortunately, can be fixed easily. Loose fittings, for example, are not uncommon, especially if the heating unit is used regularly during the winter months. Tightening the screws should stop the annoying noises. It’s also likely that the blower fan and motor have inadequate lubrication. These internal parts push air through your ductwork, causing a lot of noise. If it becomes unusually loud, however, this means that they need to be greased.

• Squealing Noises

Squealing is a typical furnace noise that signifies the need for a minor tune-up. In particular, you’ll most likely need to adjust or replace a faulty drive belt. It could also mean that the blower motor’s bearings have worn out. To accurately pinpoint the source of the noise, get in touch with your local heating services technician as soon as possible.

• Whistling Noises

A few things could be causing your furnace to produce whistling noises. One of them is the presence of tiny gaps in your ductwork. You might hear whistling coming from a small hole near the point where the ductwork and the furnace connect, particularly close to the blower. Another reason for the whistling noise is dust and dirt clogging the furnace filter. The fan, in turn, sucks air from anywhere it can. Consider removing the filter to see if the noise stops. If it’s too dirty, you’ll need to change it. This way, you’ll not only stop the noise, but also prevent your furnace’s fan motor from wearing down.

Noisy Furnace: Is It a Serious Problem?

It’s never a good idea to ignore a loud furnace, no matter how tempting it may be to do so. Any time this happens, it means something is going wrong inside the unit. Depending on the issue, you might face a wide range of problems that require immediate attention.

Keep in mind that a noisy furnace operates inefficiently. It may not look like it’s getting close to becoming a hazard to everyone in your household, but it will still be problematic. Ignoring these noises for a long time will cause the unit to expend too much energy keeping your home comfortable. This, unfortunately, will shorten its expected lifespan, not to mention cause your heating bills to skyrocket and waste precious amounts of fuel.

A noisy furnace can be an indication of more issues in the future. A loose blower belt, for instance, may start as a minor issue. Over time, however, it will work itself looser and looser until the fan stops working. Your furnace will stop working out of nowhere, which is the last thing you want to happen during the cold winter months. Addressing such problems right away with inspections and repairs minimizes the chances of your heating equipment’s working parts getting damaged and requiring replacement.

In some instances, a loud furnace can become a threat to your and your family. Remember that it utilizes combustion to provide indoor comfort whenever the weather gets cold outside. When something goes wrong, there’s a major risk of injuries and/or property damage. Delayed ignition due to excess dirt buildup inside the furnace, especially on the burners, can cause gas to build up to such high levels that an explosion or fire could occur. In addition, a loose exhaust pipe or damaged heat exchanger can cause carbon monoxide to leak indoors.

Dealing With a Loud Furnace

A loud furnace can be fixed with a bit of troubleshooting. Check the access panel to make sure all screws and fittings are properly tightened and secured. To ensure your safety and your furnace’s continued performance, it would be in your best interest to contact a certified contractor specializing in HVAC repairs and installations. The technician can locate the source of the noise and perform the necessary repairs to get your equipment back up and running smoothly again. They may, however, recommend replacing the whole system if they find that it’s close to the end of its lifespan.

W.E. Beavers Jr. Heating & Cooling  has been providing local homeowners with top-notch HVAC installation, repair and maintenance services for over two decades. Our technicians are factory-trained and have the latest diagnostic tools and equipment to quickly and accurately determine the issue with your heating or cooling system. Call (703) 897-5505  or fill out our contact form to   schedule an appointment.