A clogged air filter forces your heating system to push air through a blocked path, which can make it run longer and work harder. It can also reduce comfort, leaving some rooms colder than others. This is one of the easiest maintenance tasks in the house, yet it is often forgotten until something goes wrong.

Check the filter now and then during heating season and replace it when it looks gray and dusty. How often you need to change it depends on the filter type, whether you have pets, and how much your system runs. Your system's manual or the filter packaging usually offers guidance, and keeping a few spares on hand makes it easier.

While you are at it, consider scheduling a professional tune-up if your system has not been serviced in a while. A technician can check for worn parts, clean components and spot small problems before they turn into expensive repairs. Also make sure vents and returns throughout the house are not blocked by furniture or rugs.