While you have your furnace running this winter you might hear some strange noises. Some noises are normal and harmless but others may indicate system trouble. Here are a list of noises and what they may mean. If you hear a whining noise out of your furnace it may have an issue. Furnaces will whine when the blower motor is starting to go bad. This is something you should have looked at and fixed right away. Your blower belt might be slipping which can also cause a whining noise. Whining is something that should be looked at right away so make sure to turn the furnace off and call Bartlett Heating and Air. A loud bang on start up is common. That bang is just your metal duct work expanding and contracting with the air being forced through it. That is not a reason for worry typically unless it gets bad enough that it starts to break your ducts. You can also get a bang because of a dirty furnace. A dirty furnace will slow ignition causing a gas buildup that eventually ignites and causes a mini explosion. It is recommended that you get a furnace cleaning each fall, it will prevent the loud bang on start up and make your furnace much more efficient. If your furnace makes a scraping sound when it turns on you may have loose or broken parts that are rubbing on each other. The blower wheel needing attention is a big culprit of this noise. This is something that needs attention right away. All furnaces make odd noises every now and then but it you hear a new and unusual noise, make sure to call Bartlett Heating and Air right away!