Is your furnace making noise? If the noises are not too loud, you may be tempted to just ignore them. After all, if your furnace is still blowing out warm air, the problem can't be too bad -- right? Well, not necessarily. Furnace noises can have any number of possible causes; some of which are more worrisome than others. Here are three possible reasons why your furnace is making noise.

Dirt on the Burners

If the noise sounds like a "boom" or a "poof" when the furnace first turns on, but then it is over, then the problem could be that dirt has accumulated on the burner. What you are hearing is the dirt catch on fire when the furnace first turns on. Check to make sure you have a filter in place and that it is pushed all of the way down in the filter slot. The lack of a filter is the most common reason why a furnace burner would get dirty.

Expanding Ducts

Ask yourself whether the noise is really coming from the furnace or if it is coming from the ducts. Listen closely. Does the noise sound like it's coming from within the walls? If so, it may just be the duct work expanding and contracting as it changes temperature. There's no easy fix for this, but luckily, it does not present any hazards beyond the annoyance of the noise. The noise won't be as obvious when it's colder outside and the heat is kicking on more often since the ducts will stay warm more constantly. 

A Torn Belt

Your furnace has a fan unit that propels air out into your home. This fan has a motor, and the motor has a belt -- just like the timing belt in your car. If this belt becomes frayed, it might start making a squeaking or slapping noise as your furnace runs. The noise is usually at its worst right after the furnace starts blowing out air. As the belt warms up, it may not make as much noise. It's important to get a noisy belt fixed before it breaks apart completely, as this would cause the blower motor to fail.

Noisy furnaces are sometimes just an annoyance, but other times, they need repairs. Contact a home furnace repair company to come look at your system and be sure. You are better safe than sorry when it comes to furnace repairs.