You can save money and energy in your home by having your heating system serviced once a year and regularly replace furnace filters. Check your filter every month, especially during heavy use months. If the filter looks dirty after a month, change it. At a minimum, change the filter every 3 months. A dirty filter will slow down air flow and make the system work harder to keep you warm — wasting energy. A clean filter will also prevent dust and dirt from building up in the system — leading to expensive maintenance and/or early system failure.