As temperatures begin to slowly drop, Eli Nickerson, HVAC service and installation manager with Armstrong Comfort Solutions, likes to take a cooler, late summer day to wake up his furnace ahead of the winter.

He and his wife crack open the windows, turn the thermostat up to heating mode and give the furnace time to “stretch its legs” before it will be running around the clock to heat their home.

He recommends other homeowners test their heating system by doing the same.

“You’re gonna get a little bit of dust at the beginning of every season, so it helps to kind of in essence, burn that off,” he said. “You can listen to the system, make sure it’s coming on, make sure you feel heat coming out of your registers.”

HVAC experts like Nickerson and Bill Kennihan, owner and founder of Kennihan Plumbing & Heating, recommend hiring a professional to do routine inspections at least twice a year: once in the spring for air conditioning and once in the fall for heating.

Here are a few other useful tips for how homeowners can be more knowledgeable about their at-home heating systems ahead of the upcoming winter.

Furnaces and air conditioning systems need to be able to breathe properly to adequately condition air.

Kennihan recommended changing the filter every month for a one-inch filter and every five months for a five-inch filter. Animals who shed, like cats and dogs, can clog the filter faster.

Changing the filter of your HVAC system gets rid of any dust and debris left over from the summer and helps the furnace to work more efficiently, cutting down on how long it needs to heat a space, according to a blog by the Kennihan company.

“Even if you notice it get dirty after two, three weeks, replace it,” Nickerson added.

A clogged filter can also cause a furnace to crack its heat exchanger if it restricts enough air across the combustion chamber.

No matter the type of system someone has, Nickerson said to keep vents open and uncovered throughout the house to ensure air flow. Things like a blanket laying in front of a vent can stop the air from effectively moving through a house and it won’t condition spaces properly.

“Even if a dresser or piece of furniture is pulled away from the wall two inches, you got to give it a little bit more room than that,” he added.

Both Nickerson and Kennihan said if the system is short cycling, or turning on and off every few minutes, that is indicative of something going on.

“The fix for that could be one of 15 different things,” Nickerson said. “It’s hard to pinpoint, but it is a good telltale sign of something going on that shouldn’t be going on.”

Other warning signs to look for, according to Nickerson, are abnormal noises coming from the furnace, a furnace that is abnormally hot to the touch or a pool of water on the floor around the furnace.

Additionally, if the furnace is constantly running, it will lead to higher electricity bills. Such a situation can result from several, different issues: the filter might be clogged, the thermostat’s fan might need switched to ‘auto’ rather than ‘on’ or the installed furnace is too big or too small for the space that it is in, according to a blog by Kennihan.

The industry standard for an HVAC system is about 10 to 15 years with good maintenance, though some can last for 20 to 25 years, Nickerson said.

The best way to maintain the longevity of an HVAC system is through proper installation and regular, preventive care, Kennihan said.

Both recommended keeping carbon monoxide detectors throughout the home.

Carbon monoxide, which is known as the “silent killer,” is a colorless, odorless gas that is undetectable to human sense, but if inhaled, it can build up in the blood and pose serious health risks to those breathing it in.

Each year, more than 400 Americans die from unintentional carbon monoxide poisoning not linked to fires, more than 100,000 visit an emergency department and more than 14,000 are hospitalized, according the U.S. Centers for Disease Control and Prevention.

Nickerson said at Armstrong, they typically conduct a 21-point inspection to ensure everything from inspecting the heat exchanger to testing all safety switches is operating smoothly.

At Kennihan, they service similarly, setting up combustion checks for heating system and ensuring furnaces have the right airflow, among a plethora of other things.

“Make sure your filters are clean and ready to go; and other than that everything else would be kind of a technical inspection of all components individually by an HVAC company,” Nickerson said.

The heating inspection does not necessarily need to occur in the fall either.

“If you do that first initial check and the furnace comes on and runs and you don’t see anything and say it runs for an hour, you’re going to be OK to run. As long as you have maintenance done at some point during the season or right before, it’ll be OK,” Nickerson said.