I turned on my heater yesterday and it sounded like an airplane was landing. When I first turned it on, the fan was making a lot of noice - like it was having a hard time starting up. The heater worked and was blowing warm air, but the fan was noisy. Last year we had the same sound and we took the squirrel cage out, cleaned it up a bit and put it back. It worked fine until yesterday when it started making that noise again. Am I looking at a new furnace? What is an approximately price range? Is the price based upon the square footage of the home?

Is this an older model with a belt drive? They typically have oil cups. Make sure belt is tensioned properly. Furnaces are relatively inexpensive unless you get a fancy multi stage and multi speed. Get a basic 82% IF needed. Not exactly based on square footage but that enters into the factoring. Window, shading, external heat load, location etc, impact size.