If you own a furnace, you'll need to keep it dust-free. Small particles of dust come in the air intake, and some will make it through the air filter and into the furnace's combustion chamber.
When dust builds up in your furnace, it degrades its efficiency. Dusty burners no longer receive the right air flow mixture, so the gas won't combust cleanly. This impairs efficiency and increases the amount of toxic gases (such as carbon monoxide) that it produces.
That humble little home that you happened to find by chance can end up being a great investment and the house of your dreams at the same time. Perhaps it's a foreclosure listing, or maybe you're a newlywed looking to own for the first time, and the two of you are enthusiastic about fixing up an old home with some charm. Either way, you will have some work cut out for you.