"The best thing to do is schedule maintenance before the heating season is in full swing. But, if you’re not ready for that, there are a few steps you can take: Before you do anything, inspect your unit to make sure nothing flammable has been stored next to the furnace over the summer. Be sure to run your heater before you need it to eliminate the chance it won’t work on the first cold night you turn it on. Dirty air filters restrict airflow and reduce efficiency – sometimes even damaging your unit. Change the filters regularly."