Dean Rosenback inspects dozens of furnaces each week. Around this time of year, more people call him to make sure their heat works.
"It does collect dust," said Rosenback. "The filtration system is being used yearlong so this guy is getting clogged up."
After the summer season, insects and other bugs could creep into your system too. Any of those issues could spark fires. Rosenback said you should get your furnace looked at before starting it up for the first time each season.
"That way we can find those problems before it's in the middle of the night and it's ten degrees outside and we have to go out there and get it fixed at that point," said Rosenback.
Champaign Fire Captain Dave Ferber said the number of calls the department gets go up during the winter. Many of those are heat-related blazes.
"Most of the time when we get there, it's just confined to the device itself," said Ferber.
But if it's not, ultimately it can destroy the entire house. And flames aren't the only things you should be careful of.
"Anytime we're using a gas-fired appliance, not only just a furnace, the possibility of carbon monoxide being introduced is there," said Rosenback.
Experts said you should make sure to change your filters on a regular basis and dust around the outside of your furnace.