Most people don't give their thermostats a second thought until they go to replace them. But the truth is, they have evolved a lot over the years. They have come along way from those common round dials mounted on the wall. They have become very sophisticated. Today they are a key component of a hvac system that can save the homeowner a lot of money.  There are many types and models available. So how is one expected to know what is right for their particular system? Hopefully this information will help.