Furnace Noises (And What They Might Mean)

Have you been hearing strange noises or things going bump in the night? If so, there’s no reason to call your local Ghostbusters. It’s probably coming from your furnace. And while they might not be haunted sounds, they should be a cause for concern. 

Unusual noises are one of the main indicators that something isn’t quite right. Some furnace noises are normal such as a slight hum (especially when it starts up). More aggressive noises such as banging or rattling, could indicate a serious issue.

If you’ve recently heard unusual noises coming from your furnace, take them as a sign to get in touch with your local HVAC tech. This can save you hundreds, if not thousands, down the line on more costly repairs. 

Common Furnace Noises and What They Mean

So, you might be thinking, “Why is my furnace making noise at all?”

One of the good things about furnace noises is that every noise has a unique cause and effect. Let’s look at some of the most common furnace noises and how to translate them.

Furnace Troubleshooting Noises

Below are some of the most common noises associated with a home HVAC system that could require furnace repair for unusual noises. Also, keep in mind with older furnaces some repairs or replacements may simply be the age of the unit.

Banging or Popping

Banging noise from furnace worrying you? Or if your furnace is making a popping noise, it’s often the result of one of three things:

• Expanding or contracting ductwork

• Dirty burners

• Ignition issues.

The best solutions are to try and clean your burners or get in touch with a professional HVAC tech to check for delayed ignition.

Rattling

Some of the biggest furnace rattling noise causes include loose panels or components. However, if there is any debris floating around in your system, you might hear a rattling noise as well. If getting in your furnace and tightening any loose parts doesn’t do the trick, you should schedule an inspection for internal issues.

Squealing or Screeching

Possibly the worst and most obvious sounds, squealing and screeching often come from worn-out blower motor belts or failing bearings. High pitched squealing issues require a more experienced hand, as they often necessitate belt and motor repairs. 

Humming

While you’ll often experience a quiet humming with normal motor operation, any excessive humming could indicate more serious electrical issues. In this case, we recommend having a seasoned technician inspect the wiring or motor on your furnace.

Clicking

A pointy clicking sound, just like one you might hear when trying to start a dead car battery, is usually the fault of a bad ignition system or relay switch. You can usually check the thermostat to see if your furnace is running at all. If not, call in for professional repair.

Booming

If you experience delayed ignition or a buildup of gas in the combustion chamber, you’ll likely hear an accompanying noise that can best be described as a ‘boom.’ If you hear a sound like this, turn off the furnace immediately and get in touch with a professional.

Whistling

Lastly, we have a whistling sound, which is similar to that of a hot teapot. The culprits are usually blocked vents or clogged filters that are restricting airflow. The solution is often as simple as cleaning or replacing your dirty air filters if they’re dirty or clearing your vents if they’re blocked.

When to Be Concerned About Furnace Noises

So, when should you actually not ignore these strange noises you’re hearing in your home? 

Well, if the strange furnace noises you’re experiencing are loud or consistent, they likely require professional attention. Don’t ignore noises unless you want bigger problems to deal with.

Too often, we have clients who don’t want to pay for small repairs and end up with failed systems or hazardous issues, like gas leaks. Being vigilant and proactive is the best way to make sure your home is always comfortable and in the best shape possible.

Preventing Furnace Noises with Regular Maintenance

One of the best ways to prevent issues with a heating system and furnace troubleshooting issues in the first place is an annual furnace tune-up schedule.

By scheduling even one inspection with your local HVAC tech each year, you can keep the components of your furnace clean and functioning properly.

There are even things you can do on your own today! For example, by replacing your filters regularly, you can prevent airflow-related noises. Check out our guide, "Stay Warm This Winter: Furnace Maintenance in Vancouver, WA,” to learn more!

DIY Steps to Address Minor Furnace Noises

If you’re the kind of homeowner who has a DIY mentality, we applaud you! Luckily, there are several steps that don’t require the hand of a professional that you can take to keep your furnace in the best condition:

• Check for loose components: Inspect the entirety of your system to see if there are any loose screws or panels that you can tighten. 

• Inspect and replace filters: We recommend changing your filters every three months, but if they’re especially dirty, you can replace them sooner.

• Assess your vents: Check your vents to make sure they’re free of any debris or blockages. 

Anything beyond these basic steps and we recommend calling a professional.

When to Call a Professional

If you’ve been through the basic steps above and you’re still hearing what we refer to as “red flag” noises (booming, clicking, or persistent rattling), it’s a good idea to seek professional help. 

Seasoned techs have the experience and training to diagnose and resolve issues safely, especially when they are gas or electrical-related.

Our blog, 9 Indicators You Need Furnace Repair in Vancouver WA., offers a detailed outline of more serious problems that require professional attention.

Upgrading to a Quieter, High-Efficiency Furnace

If your furnace has reached the end of its lifespan, or you’re just looking for a quieter and more efficient furnace, it might be worth considering an upgrade.

A new, energy-efficient furnace can save you tons of money in the long run and keep your home comfortable, even during the coldest times of the year. 

Check out our blog, High Efficiency Gas Furnaces: A Simple Guide for Homeowners, for more information on the latest in high-end furnace design and technology. 

Final Thoughts on Furnace Noises and Maintenance

We hope that this guide didn’t scare you away. It’s important to note that furnace noises don’t always mean expensive repairs. However, that doesn’t mean you should ignore loud furnace noises when running your system either.

We encourage you to schedule a professional inspection if you’re unsure about a noise you’re experiencing. Contact Miller’s Heating & Air for expert diagnostics and repairs here in Vancouver, WA!