Your furnace is essential for maintaining comfort in your home during the winter months. So, hearing unusual noises from your furnace can be quite alarming. Your furnace will make different sounds depending on the specific problem it's experiencing. Don't ignore these sounds you may hear from a malfunctioning furnace.

Screeching or Squealing

Screeching or squealing can be attributed to worn belts or bearings in most machinery, and your furnace is no exception. Bearings in the blower motor may screech when they're worn as a warning that it's time to replace them. Worn bearings can occur due to age or overheating inside your furnace.

The fan belt may become frayed or cracked in furnaces with belt-drive blower motors. Worn belts often produce squealing noises before they break and the furnace blower stops working completely. Furnace fan belts typically have a lifespan of around one year, and they are easy and inexpensive to replace annually.

Scraping or Grinding Noises

Metal-on-metal scraping or grinding noises are hard to ignore, especially when they come from your furnace. These sounds occur when a moving part in your furnace makes contact with another component or the furnace housing. The cause behind scraping and grinding furnace noises can usually be narrowed down to the blower wheel or a broken blower motor mount.

If the blower wheel is loose or unbalanced, it may scrape against the blower wheel case. A broken or loose blower motor mount can cause the entire blower assembly to grind against other parts in your furnace. Call for repairs promptly to prevent additional damage to your furnace blower motor.

Popping and Clicking Sounds

Popping and clicking sounds from your furnace usually point to an issue with the ignition system. In a gas furnace, the burners can become clogged with dust and soot over time. Dirt on furnace burners can delay their ignition, during which gas will build up inside the burner. When it finally ignites, the built-up gas will combust with a loud pop.

A repeated clicking sound when you try to start your furnace could be the result of a failed spark ignitor. This is especially likely if your furnace won't start at all. The click is the sound of the igniters attempting and failing to create a spark. In most furnaces, igniters are modular components that can be replaced when they reach the end of life.

Understanding the sounds that indicate furnace problems will help you schedule early repairs before the damage becomes more serious. Consult a furnace repair professional whenever you hear unusual noises from your furnace.