Furnaces can make quiet humming noises during operation ... or a loose blower wheel, then the furnace may grow louder or start to make unfamiliar sounds that indicate a more serious issue.

A heater making gurgling ... some common noise-related furnace issues. A well-maintained furnace is more efficient and can reduce energy consumption and lower energy bills. A buzzing furnace ...

We often take our furnace for granted until something causes it to stop working ... He says, "If your system makes a buzzing sound when you start it and then shuts off, it's likely due to ...