Winter’s tough enough without your furnace dying or not putting out enough heat. And when it comes to furnaces, an ounce of prevention truly is worth a pound of cure. So here are some basic maintenance tasks that you can do to ensure that your natural gas or propane-fueled furnace stays running in peak condition all winter. Together, these tasks will take you less than three hours to do, cost only a few dollars, and require a few basic hand tools. That’s pretty cheap insurance for a worry-free winter of cozy, cost-effective warmth.