Why is My Furnace So Loud?

loud furnace

Furnaces are known to make some noise during regular function. However, these noises are a sign that you may have a problem. The sound of the furnace turning on and off may be no reason to worry, but anything you hear accompanying the normal activity of the furnace should be investigated to rule out damage and needed repairs.

Constant Cycling

In some cases, the annoying sound you hear is that of the furnace cycling on and off, all day long. Your furnace will turn on and off regularly throughout the day to keep the house to the appropriate temperature. However, if you notice that the furnace seems to always be on, or if it is only staying on for a few minutes before cycling off again, you may have a problem. Dirty air filters force the furnace to turn on more often. You may also have a thermostat with an inaccurate temperature gauge, or a furnace that was not sized large enough for your home’s needs. This issue lowers your overall HVAC efficiency and can increase your heating bills.


The blower in your furnace is what sends the heated air through your ductwork into the various rooms of your home. When that blower is not working very well, you may observe a squealing noise. The noise is likely coming from a loose or slipping blower belt, or another problem with the blower motor. You should address this problem as soon as possible after you hear it, because a broken blower could mean no heat in your home.

Grinding or Screeching

Since there are so many parts to the blower that could malfunction, they may make different sounds. The sound of metal grinding on metal is a terrible thing to listen to, and you may be tempted to turn off your furnace to stop the noise. That grinding sound is often related to the blower bearings or belt. Either or both may require furnace repair in Sacramento, in order for the sound to stop.

Rattling or Popping

If you have been doing some personal maintenance for your furnace, it is not surprising to hear a rattling sound when you turn the furnace back on. This may result from loose cover panels. Make sure that they are properly replaced and tightened so that they do not rattle under the pressure of the air handler. When you have metal ductwork, you may also hear a popping sound when your furnace turns on and off. This is caused by the expansion and contraction of the ductwork. If your ductwork is too small or you have closed vents to various rooms, you may be more likely to notice this particular noise.

The feel of warm air coming through your vents is no comfort when you hear loud, intimidating noises coming from your furnace. If you notice any of these noises, contact Ace Plumbing for expert furnace repair in Sacramento.