If you suddenly notice one day that your furnace is awfully noisy and you're not sure if it's within the normal ranges of noise for your type of furnace, there are several steps you can take. If you determine that the noise is abnormal, it's time to call in a technician, such as from Norris Mechanical; but for now, use these three tips to help you decide if your furnace is likely to have a problem or if it's just making tons of noise because it's a big loud piece of machinery. 

1. Assess the type of noise

Some furnace noises are hard to tell apart, but if you can distinguish a new type of sound that you aren't used to hearing from your furnace, you could have a problem. Listen to the noise and try to figure out if you're hearing any of the following types of sounds:

  • a bang when you start the furnace
  • a whooshing or whistling sound, especially in the ducts
  • a rattling sound in the ducts
  • an additional motor sound (this is especially hard to distinguish)
  • a screeching sound, like metal on metal

Though some indicate more serious problems than others, any of these sounds can indicate an abnormality in your furnace's workings. You may want to call in a technician to diagnose the sounds, especially if outside temperatures are extremely low and the sound is extremely annoying, or you may want to do your own research on the likely causes of the specific noise you're hearing. Before you take either of these steps, though, continue on to the next two tips.

2. Compare to normal noise levels

If you've had your furnace for a while, you're probably fairly familiar with what it sounds like during normal operation and startup. If you're not the person who normally turns the furnace on, find that person and ask him or her if the sounds you're hearing are new or if they're normal. If you've recently moved in, try to get in touch with the previous owner for information on the furnace's quirks. Some types of sounds, such as rattling and whooshing, may be perfectly normal for your furnace system and not represent a crisis at all. You may still want to get the noise fixed if it bothers you now that you've noticed it, though.

3. Find out if the noise is localized

It's crucial to find out where the noise is coming from. For example, if the sound you're hearing is a sort of whooshing and it's localized in the ductwork near the furnace itself, you may have an easy-to-fix problem such as a hole in the ductwork that simply needs plugging. If the sound is coming from the furnace itself and is also an unusual sound that the furnace doesn't normally make, you should assume you have a problem that needs immediate attention from a repair technician. But either way, finding out where the sound is being created will help in the diagnostic process. 

Using these three steps, you can decide if that noise you're hearing is a threat and whether you should ignore it or call for help right away. Remember to try obvious fixes, like changing the air filter, before you hire a technician.